Lesi sihloko siyingxenye yesihloko socwaningo esithi “Ubuchwepheshe obuthuthukisiwe bokulungisa izinto eziphilayo kanye nezinqubo zokuvuselela izinto ezihlanganisiwe eziphilayo (i-SOC). Buka zonke izihloko ezingu-14
Ama-polycyclic aromatic hydrocarbons (ama-PAH) anesisindo esiphansi sama-molecule njenge-naphthalene kanye nama-naphthalene afakwe esikhundleni (i-methylnaphthalene, i-naphthoic acid, i-1-naphthyl-N-methylcarbamate, njll.) asetshenziswa kabanzi ezimbonini ezahlukahlukene futhi anobuthi be-genotoxic, aguqula i-mutagenic kanye/noma abangela umdlavuza ezintweni eziphilayo. Lawa ma-compounds e-organic (ama-SOC) noma ama-xenobiotics abhekwa njengezinto ezingcolisayo eziza kuqala futhi abeka usongo olukhulu emvelweni womhlaba kanye nempilo yomphakathi. Ukuqina kwemisebenzi yabantu (isb. ukwenziwa kwegesi yamalahle, ukuhluzwa kwamafutha, ukukhishwa kwezimoto kanye nezicelo zezolimo) kunquma ukuhlushwa, isiphetho kanye nokuthuthwa kwala ma-compounds atholakala yonke indawo futhi ahlala njalo. Ngaphezu kwezindlela zokwelapha/zokususa ngokomzimba namakhemikhali, ubuchwepheshe obuluhlaza nobunobungani nemvelo njengokulungiswa kwe-bio, obusebenzisa ama-microorganisms akwazi ukonakalisa ngokuphelele ama-POC noma ukuwaguqula abe yimikhiqizo engeyona enobuthi, buvele njengendlela ephephile, engabizi futhi ethembisayo. Izinhlobo ezahlukene zamabhaktheriya eziyingxenye ye-phyla Proteobacteria (Pseudomonas, Pseudomonas, Comamonas, Burkholderia, kanye ne-Neosphingobacterium), ama-Firmicutes (Bacillus kanye ne-Paenibacillus), kanye ne-Actinobacteria (Rhodococcus kanye ne-Arthrobacter) enhlabathini microbiota zibonise ikhono lokonakalisa amakhemikhali ahlukahlukene e-organic. Izifundo ze-metabolic, i-genomics, kanye nokuhlaziywa kwe-metagenomic kusisiza siqonde ubunzima be-catabolic kanye nokwehlukahluka okukhona kulezi zinhlobo zokuphila ezilula, ezingasetshenziswa kabanzi ukuze kutholakale i-biodegradation ephumelelayo. Ukuba khona kwesikhathi eside kwama-PAH kuholele ekuveleni kwezinhlobo ezintsha zokuwohloka ngokudluliselwa kwezakhi zofuzo okuvundlile kusetshenziswa izakhi zofuzo ezifana nama-plasmids, ama-transposons, ama-bacteriophages, iziqhingi ze-genomic, kanye nezakhi ezihlanganisiwe ezihlanganisiwe. I-biology yezinhlelo kanye nobunjiniyela bezakhi zofuzo zezinhlobo ezithile noma imiphakathi yamamodeli (ama-consortia) kungenza kube lula ukuvuselelwa kwezakhi zofuzo okuphelele, okusheshayo nokuphumelelayo kwala ma-PAH ngemiphumela yokusebenzisana. Kulesi sibuyekezo, sigxila ezindleleni ezahlukene ze-metabolic kanye nokuhlukahluka, ukwakheka kwezakhi zofuzo kanye nokuhlukahluka, kanye nezimpendulo zamaseli/ukuzivumelanisa nezimo kwe-naphthalene kanye namagciwane abhubhisa i-naphthalene afakwe esikhundleni. Lokhu kuzohlinzeka ngolwazi lwezemvelo lokusetshenziswa kwensimu kanye nokwenza ngcono ukucindezeleka ukuze kulungiswe kahle i-bioremediation.
Ukuthuthukiswa okusheshayo kwezimboni (amakhemikhali kaphethroli, ezolimo, emithi, udayi wezindwangu, izimonyo, njll.) kube negalelo ekuchumeni komnotho womhlaba wonke kanye nokuthuthukiswa kwezindinganiso zokuphila. Lokhu kuthuthukiswa okukhulu kuholele ekukhiqizweni kwenani elikhulu lamakhemikhali e-organic (ama-SOC), asetshenziselwa ukukhiqiza imikhiqizo eyahlukahlukene. Lawa makhemikhali angaphandle noma ama-SOC afaka ama-polycyclic aromatic hydrocarbons (ama-PAH), izibulala-zinambuzane, ama-herbicides, ama-plasticizers, amadayi, imithi, ama-organophosphates, ama-flame retardants, ama-volatil organic solvents, njll. Akhishwa emoyeni, ezindaweni zemvelo zasemanzini nasemhlabeni lapho enemiphumela eminingi, okubangela imiphumela emibi kuma-bioform ahlukahlukene ngokushintsha izakhiwo ze-physicochemical kanye nesakhiwo somphakathi (Petrie et al., 2015; Bernhardt et al., 2017; Sarkar et al., 2020). Izinto eziningi ezingcolisa umoya zinemiphumela enamandla nebhubhisayo ezindaweni eziningi eziphilayo/izindawo ezishisayo eziphilayo (isb. amadwala e-coral, amaqhwa ase-Arctic/Antarctic, amachibi aphezulu asezintabeni, inhlabathi ejulile yolwandle, njll.) (Jones 2010; Beyer et al. 2020; Nordborg et al. 2020). Izifundo zakamuva ze-geomicrobiological zikhombisile ukuthi ukufakwa kwezinto eziphilayo zokwenziwa (isb. izinto ezingcolisa umoya) kanye nezinto eziphuma kuzo ebusweni bezakhiwo zokwenziwa (indawo eyakhiwe) (isb. izindawo zamagugu amasiko kanye nezikhumbuzo ezenziwe nge-granite, itshe, ukhuni nensimbi) kusheshisa ukuwohloka kwazo (Gadd 2017; Liu et al. 2018). Imisebenzi yabantu ingaqinisa futhi ibe yimbi kakhulu ukuwohloka kwemvelo kwezikhumbuzo nezakhiwo ngokungcola komoya kanye nokushintsha kwesimo sezulu (Liu et al. 2020). Lezi zinto ezingcolisa umoya zisabela ngomhwamuko wamanzi emkhathini futhi zihlale esakhiweni, okubangela ukuwohloka ngokomzimba nangokwekhemikhali kwezinto. Ukubola kwezinto eziphilayo kubhekwa kabanzi njengezinguquko ezingathandeki ekubukekeni nasezimpahleni zezinto eziphilayo ezibangelwa izinto eziphilayo ezithinta ukulondolozwa kwazo (Pochon noJaton, 1967). Isenzo esengeziwe samagciwane (i-metabolism) yalezi zinhlanganisela singanciphisa ubuqotho besakhiwo, ukusebenza kahle kokulondolozwa kanye nenani lamasiko (Gadd, 2017; Liu et al., 2018). Ngakolunye uhlangothi, kwezinye izimo, ukuzivumelanisa namagciwane kanye nokusabela kulezi zakhiwo kutholakale kuzuzisa njengoba kwakha ama-biofilm kanye nezinye izingqimba ezivikelayo ezinciphisa izinga lokubola/ukubola (Martino, 2016). Ngakho-ke, ukuthuthukiswa kwamasu okulondoloza asebenzayo isikhathi eside ezikhumbuzo zamatshe, zensimbi kanye nezinkuni kudinga ukuqonda okuphelele kwezinqubo ezibalulekile ezihilelekile kule nqubo. Uma kuqhathaniswa nezinqubo zemvelo (izinqubo ze-geological, imililo yamahlathi, ukuqhuma kwezintaba-mlilo, ukusabela kwezitshalo kanye namagciwane), imisebenzi yabantu iholela ekukhululweni kwenani elikhulu lama-polycyclic aromatic hydrocarbons (ama-PAH) kanye nezinye i-organic carbon (OC) ezindaweni zemvelo. Ama-PAH amaningi asetshenziswa kwezolimo (izinambuzane kanye nezibulala-zinambuzane ezifana ne-DDT, i-atrazine, i-carbaryl, i-pentachlorophenol, njll.), imboni (uwoyela ongahluziwe, udaka/imfucuza kawoyela, amapulasitiki atholakala ku-petroleum, ama-PCB, ama-plasticizer, ama-detergent, ama-disinfectants, ama-fumigants, amaphunga kanye nezilondolozi), imikhiqizo yokunakekela umuntu siqu (izikrini zelanga, izibulala-magciwane, izixosha izinambuzane kanye nama-polycyclic musks) kanye nezibhamu (iziqhumane ezifana ne-2,4,6-TNT) zingama-xenobiotic angaba khona angathinta impilo yeplanethi (Srogi, 2007; Vamsee-Krishna noPhale, 2008; Petrie et al., 2015). Lolu hlu lungandiswa ukuze lufake amakhemikhali atholakala ku-petroleum (amafutha kaphethiloli, amafutha okugcoba, ama-asphaltenes), ama-bioplastics anesisindo esikhulu sama-molecule, kanye noketshezi lwe-ionic (Amde et al., 2015). Ithebula 1 libala ukungcola okuhlukahlukene okunuka kamnandi kanye nokusetshenziswa kwawo ezimbonini ezahlukene. Eminyakeni yamuva nje, ukukhishwa kwezinto eziphilayo eziguquguqukayo, kanye ne-carbon dioxide kanye nezinye izinto ezibangela ukushisa, kuye kwaqala ukwanda (Dvorak et al., 2017). Kodwa-ke, imiphumela yabantu idlula kakhulu eyemvelo. Ngaphezu kwalokho, sithole ukuthi ama-SOC amaningana ayaqhubeka ezindaweni eziningi zemvelo futhi atholakale njengezinto ezingcolisayo ezivelayo ezinemiphumela emibi kuma-biomes (Isithombe 1). Izinhlangano zemvelo ezifana ne-United States Environmental Protection Agency (USEPA) zifake eziningi zalezi zinto ezingcolisayo ohlwini lwazo olubalulekile ngenxa yezakhiwo zazo ezinobungozi, ezinobuthi, eziguqula i-geno, kanye ne-carcinogenic. Ngakho-ke, imithetho eqinile yokulahla kanye namasu asebenzayo okwelapha/ukususa imfucuza ezindaweni zemvelo ezingcolile iyadingeka. Izindlela ezahlukene zokwelapha ngokomzimba namakhemikhali ezifana ne-pyrolysis, ukwelashwa kokushisa kwe-oxidative, umoya ovunguzayo, ukugcwalisa udoti, ukushiswa, njll. aziphumeleli futhi ziyabiza futhi zikhiqiza imikhiqizo ebolayo, enobuthi futhi kunzima ukuyiphatha. Njengoba ulwazi lwezemvelo emhlabeni jikelele lukhula, ama-microorganism akwazi ukonakalisa lawa ma-compound kanye nezinto eziphuma kuwo (njenge-halogenated, i-nitro, i-alkyl kanye/noma i-methyl) adonsela ukunaka okwandayo (Fennell et al., 2004; Haritash noKaushik, 2009; Phale et al., 2020; Sarkar et al., 2020; Schwanemann et al., 2020). Ukusetshenziswa kwala ma-microorganisms afaneleka kuphela noma emasikweni axubile (amakoloni) ukususa ama-compounds anephunga elimnandi kunezinzuzo ngokuphepha kwemvelo, izindleko, ukusebenza kahle, ukusebenza kahle, kanye nokusimama. Abacwaningi bahlola nokuhlanganiswa kwezinqubo zama-microbial nezindlela ze-electrochemical redox, okungukuthi izinhlelo ze-bioelectrochemical (BES), njengobuchwepheshe obuthembisayo bokwelapha/ukususa ukungcola (Huang et al., 2011). Ubuchwepheshe be-BES budonsele ukunaka okwandayo ngenxa yokusebenza kahle kwayo okuphezulu, izindleko eziphansi, ukuphepha kwemvelo, ukusebenza kwezinga lokushisa legumbi, izinto ezihambisana ne-bio, kanye nekhono lokubuyisa imikhiqizo ebalulekile (isb. ugesi, uphethiloli, namakhemikhali) (Pant et al., 2012; Nazari et al., 2020). Ukufika kwe-high-throughput genome sequencing kanye namathuluzi/izindlela ze-omics kuhlinzeke ngolwazi olusha mayelana nokulawulwa kwezakhi zofuzo, i-proteomics, kanye ne-fluxomics yezindlela ze-microorganisms ezahlukahlukene eziwohlokayo. Ukuhlanganisa la mathuluzi ne-systems biology kuye kwathuthukisa ukuqonda kwethu ukukhethwa kanye nokulungiswa kahle kwezindlela ze-catabolic eziqondiwe kuma-microorganisms (okungukuthi, ukwakheka kwe-metabolic) ukuze kufezwe i-biodegradation ephumelelayo nephumelelayo. Ukuze sakhe amasu okulungisa i-bioremediation asebenzayo sisebenzisa ama-microorganisms afanele, sidinga ukuqonda amandla e-biochemical, ukuhlukahluka kwe-metabolic, ukwakheka kwezakhi zofuzo, kanye ne-ecology (i-autoecology/synecology) yama-microorganisms.
Isithombe 1. Imithombo kanye nezindlela zama-PAH angenama-molecule aphansi ngokusebenzisa izindawo ezahlukene zemvelo kanye nezici ezahlukahlukene ezithinta i-biota. Imigqa edwetshwe ngemigqa imelela ukusebenzisana phakathi kwezinto zemvelo.
Kulesi sibuyekezo, sizame ukufingqa idatha mayelana nokuwohloka kwama-PAH alula njenge-naphthalene kanye nama-naphthalene afakwe esikhundleni yizinhlobo ezahlukene zama-bacterial isolates ezihlanganisa izindlela ze-metabolic kanye nokuhlukahluka, ama-enzyme ahilelekile ekuwohlokeni, ukwakheka/ukuqukethwe kwezakhi zofuzo kanye nokuhlukahluka, izimpendulo zamaseli kanye nezici ezahlukene zokulungiswa kwezakhi zofuzo. Ukuqonda amazinga e-biochemical kanye nama-molecule kuzosiza ekuboneni izinhlobo ezifanele zomsingathi kanye nobunjiniyela bazo obuqhubekayo bezakhi zofuzo ukuze kulungiswe ngempumelelo izinto ezinjalo ezingcolisayo ezibalulekile. Lokhu kuzosiza ekwakheni amasu okusungula i-bacterial consortia yendawo ethile ukuze kulungiswe ngempumelelo izinto eziphilayo.
Ukuba khona kwenani elikhulu lamakhemikhali anobuthi futhi ayingozi anuka kamnandi (okwanelisa umthetho we-Huckel 4n + 2π electrons, n = 1, 2, 3, …) kubeka usongo olukhulu ezindabeni ezahlukene zemvelo ezifana nomoya, inhlabathi, inhlabathi, kanye nomhlaba kanye namanzi angaphansi komhlaba (Puglisi et al., 2007). Lawa makhemikhali anezindandatho ze-benzene eyodwa (i-monocyclic) noma izindandatho ze-benzene eziningi (i-polycyclic) ezihlelwe ngendlela eqondile, e-angular noma yeqoqo futhi zibonisa ukuzinza (ukuzinza/ukungazinzi) endaweni ezungezile ngenxa yamandla aphezulu okuzwakala kabi kanye nokungazwakali (ukungazwakali), okungachazwa ngokungezwani kwawo namanzi kanye nesimo esinciphile. Uma indandatho enuka kamnandi ithathelwa indawo yi-methyl (-CH3), i-carboxyl (-COOH), i-hydroxyl (-OH), noma amaqembu e-sulfonate (-HSO3), iba nokuqina okukhulu, inobuhlobo obuqinile nama-macromolecule, futhi i-bioaccumulative ezinhlelweni zezinto eziphilayo (Seo et al., 2009; Phale et al., 2020). Amanye ama-polycyclic aromatic hydrocarbons (LMWAHs) anesisindo esiphansi sama-molecule, njenge-naphthalene kanye nezinto eziphuma kuyo [i-methylnaphthalene, i-naphthoic acid, i-naphthalenesulfonate, kanye ne-1-naphthyl N-methylcarbamate (carbaryl)], afakiwe ohlwini lwezinto ezingcolisa izinto eziphilayo ezibaluleke kakhulu yi-US Environmental Protection Agency njengezinobuthi be-genotoxic, i-mutagenic, kanye/noma ezibangela umdlavuza (Cerniglia, 1984). Ukukhululwa kwaleli klasi lama-NM-PAH endaweni ezungezile kungabangela ukunqwabelana kwalezi zinhlanganisela kuwo wonke amazinga ochungechunge lokudla, ngaleyo ndlela kuthinte impilo yezindawo zemvelo (Binkova et al., 2000; Srogi, 2007; Quinn et al., 2009).
Imithombo nezindlela zama-PAH eziya kwi-biota ngokuyinhloko ngokufuduka kanye nokusebenzisana phakathi kwezingxenye ezahlukene zemvelo ezifana nomhlabathi, amanzi angaphansi komhlaba, amanzi angaphezulu komhlaba, izitshalo kanye nomkhathi (Arey no-Atkinson, 2003). Isithombe 1 sibonisa ukusebenzisana kanye nokusatshalaliswa kwama-PAH ahlukene anesisindo esiphansi sama-molecule ezindaweni zemvelo kanye nezindlela zawo zokuya ekuchayweni yi-biota/abantu. Ama-PAH abekwa ezindaweni ngenxa yokungcoliswa komoya kanye nangokufuduka (ukukhukhuleka) kokukhishwa kwezimoto, amagesi okukhipha umoya ezimbonini (ukufakwa kwegesi yamalahle, ukushiswa kanye nokukhiqizwa kwe-coke) kanye nokufakwa kwawo. Imisebenzi yezimboni efana nokukhiqiza izindwangu zokwenziwa, udayi kanye nopende; ukulondolozwa kwezinkuni; ukucubungula irabha; imisebenzi yokukhiqiza usimende; ukukhiqizwa kwezibulala-zinambuzane; kanye nezicelo zezolimo yimithombo emikhulu yama-PAH ezinhlelweni zomhlaba kanye nasemanzini (Bamforth noSingleton, 2005; Wick et al., 2011). Izifundo zikhombisile ukuthi inhlabathi ezindaweni zasemadolobheni nasemadolobheni, eduze kwemigwaqo emikhulu, nasemadolobheni amakhulu isengozini enkulu ye-polycyclic aromatic hydrocarbons (ama-PAH) ngenxa yokukhishwa kwegesi okuvela ezitshalweni zamandla, ukushisa kwezindlu, imithwalo yezimoto zomoya kanye nemigwaqo, kanye nemisebenzi yokwakha (Suman et al., 2016). (2008) ibonise ukuthi ama-PAH asenhlabathini eduze kwemigwaqo eNew Orleans, eLouisiana, e-USA ayephezulu njengo-7189 μg/kg, kanti endaweni evulekile, ayengu-2404 μg/kg kuphela. Ngokufanayo, amazinga e-PAH aphezulu njengo-300 μg/kg abikwe ezindaweni eziseduze nezindawo zokufaka igesi yamalahle emadolobheni amaningana ase-US (Kanaly and Harayama, 2000; Bamforth and Singleton, 2005). Inhlabathi evela emadolobheni ahlukahlukene aseNdiya njengeDelhi (Sharma et al., 2008), i-Agra (Dubey et al., 2014), iMumbai (Kulkarni kanye neVenkataraman, 2000) kanye neVisakhapatnam (Kulkarni et al., 2014) ibikwe ukuthi iqukethe amazinga aphezulu ama-PAH. Amakhemikhali anomsoco amuncwa kalula ezinhlayiyeni zomhlabathi, izinto eziphilayo kanye namaminerali obumba, ngaleyo ndlela abe yizicucu ezinkulu zekhabhoni ezindaweni zemvelo (Srogi, 2007; Peng et al., 2008). Imithombo emikhulu yama-PAH ezindaweni zemvelo zasemanzini imvula (imvula emanzi/eyomile kanye nomhwamuko wamanzi), ukugeleza kwamanzi emadolobheni, ukukhishwa kwamanzi amdaka, ukugcwaliswa kwamanzi angaphansi komhlaba njll. (Srogi, 2007). Kulinganiselwa ukuthi cishe ama-80% ama-PAH ezindaweni zemvelo zasolwandle atholakala ekuweni, ukuchitheka kwenhlabathi, kanye nokukhishwa kwemfucuza (Motelay-Massei et al., 2006; Srogi, 2007). Ukugcwala okuphezulu kwama-PAH emanzini angaphezulu noma i-leachate evela ezindaweni zokulahla imfucuza eqinile ekugcineni kuvuza emanzini angaphansi komhlaba, okubeka usongo olukhulu empilweni yomphakathi njengoba abantu abangaphezu kuka-70% eNingizimu naseNingizimu-mpumalanga ye-Asia bephuza amanzi angaphansi komhlaba (Duttagupta et al., 2019). Ucwaningo lwamuva olwenziwe nguDuttagupta et al. (2020) lokuhlaziya komfula (32) kanye namanzi angaphansi komhlaba (235) oluvela eWest Bengal, eNdiya, luthole ukuthi cishe ama-53% ezakhamuzi zasemadolobheni kanye nama-44% ezakhamuzi zasemaphandleni (izakhamuzi eziyizigidi ezingu-20 sezizonke) zingase zivezwe ku-naphthalene (4.9–10.6 μg/L) kanye nezinto eziphuma kuyo. Amaphethini okusetshenziswa komhlaba ahlukene kanye nokukhishwa kwamanzi angaphansi komhlaba okwandisiwe kubhekwa njengezici eziyinhloko ezilawula ukuthuthwa okuqondile (ukukhuphuka) kwama-PAH anesisindo esiphansi sama-molecule endaweni engaphansi komhlaba. Ukugeleza kwamanzi ezolimo, ukukhishwa kwamanzi angcolile kamasipala kanye nezimboni, kanye nokukhishwa kwemfucuza/udoti okuqinile kutholakale ukuthi kuthinteka ama-PAH emifuleni nasezindaweni ezingaphansi komhlaba. Ukuna kwemvula emoyeni kwandisa kakhulu ukungcola kwe-PAH. Ukugxila okuphezulu kwama-PAH kanye ne-alkyl derivatives awo (51 esewonke) kubikwe emifuleni/ezindaweni zamanzi emhlabeni jikelele, njengoMfula iFraser, uMfula iLouan, uMfula iDenso, uMfula iMissouri, uMfula i-Anacostia, uMfula i-Ebro, kanye noMfula iDelaware (Yunker et al., 2002; Motelay-Massei et al., 2006; Li et al., 2010; Amoako et al., 2011; Kim et al., 2018). Ezindaweni ezingaphansi koMfula iGanges, i-naphthalene kanye ne-phenanthrene kutholakale ukuthi yizona ezibaluleke kakhulu (ezitholakale kumasampula angu-70%) (Duttagupta et al., 2019). Ngaphezu kwalokho, izifundo zikhombisile ukuthi i-chlorine yamanzi okuphuza ingaholela ekwakhekeni kwama-PAH anobuthi kakhulu ane-oxygen futhi ane-chlorine (Manoli noSamara, 1999). Ama-PAH aqoqana kokusanhlamvu, izithelo kanye nemifino ngenxa yokumuncwa yizitshalo enhlabathini engcolile, emanzini angaphansi komhlaba kanye nemvula (Fismes et al., 2002). Izinto eziningi eziphilayo zasemanzini njengezinhlanzi, ama-mussels, ama-clam kanye nama-shrimp zingcoliswe ama-PAH ngokusebenzisa ukudla okungcolisiwe namanzi olwandle, kanye nezicubu kanye nesikhumba (Mackay noFraser, 2000). Izindlela zokupheka/zokucubungula ezifana nokosa, ukuthosa, ukubhema, ukuthosa, ukomisa, ukubhaka kanye nokupheka ngamalahle nazo zingaholela enanini elikhulu lama-PAH ekudleni. Lokhu kuncike kakhulu ekukhetheni kwezinto zokubhema, okuqukethwe kwe-phenolic/aromatic hydrocarbon, inqubo yokupheka, uhlobo lwesifudumezi, okuqukethwe komswakama, ukuhlinzekwa komoya-mpilo kanye nokushisa kokushisa (Guillén et al., 2000; Gomes et al., 2013). Ama-polycyclic aromatic hydrocarbons (ama-PAH) nawo atholakale ebisini ngezinga elihlukahlukene (0.75–2.1 mg/L) (Girelli et al., 2014). Ukuqongelela kwala ma-PAH ekudleni kuncike nasezimpahleni ze-physicochemical zokudla, kuyilapho imiphumela yazo enobuthi ihlobene nemisebenzi yomzimba, umsebenzi we-metabolic, ukumuncwa, ukusatshalaliswa kanye nokusatshalaliswa komzimba (Mechini et al., 2011).
Ubuthi kanye nemiphumela eyingozi yama-polycyclic aromatic hydrocarbons (ama-PAH) kwaziwa isikhathi eside (iCherniglia, 1984). Ama-polycyclic aromatic hydrocarbons anesisindo esiphansi sama-molecule (ama-LMW-PAH) (izindandatho ezimbili kuya kwezintathu) angabopha ndawonye kuma-macromolecule ahlukahlukene njenge-DNA, i-RNA kanye namaprotheni futhi abangela umdlavuza (i-Santarelli et al., 2008). Ngenxa yemvelo yawo yokungathandi amanzi, ahlukaniswa yi-lipid membranes. Kubantu, ama-cytochrome P450 monooxygenases axova ama-PAH abe ama-epoxide, amanye awo asabela kakhulu (isib. i-baediol epoxide) futhi angaholela ekuguqulweni kwamaseli ajwayelekile abe yilawo anomdlavuza (i-Marston et al., 2001). Ngaphezu kwalokho, imikhiqizo yokuguqulwa kwama-PAH njenge-quinones, ama-phenols, ama-epoxide, ama-diols, njll. anobuthi obukhulu kunezakhi zomzali. Amanye ama-PAH kanye nezindlela zawo zokusebenzisa umzimba zingathinta ama-hormone kanye nama-enzyme ahlukahlukene ekusebenzeni komzimba, ngaleyo ndlela zithinte kabi ukukhula, uhlelo lwezinzwa oluphakathi, izinhlelo zokuzala kanye nezokuzivikela komzimba (Swetha noPhale, 2005; Vamsee-Krishna et al., 2006; Oostingh et al., 2008). Ukuchayeka okwesikhashana kuma-PAH anesisindo esiphansi sama-molecule kubikwe ukuthi kubangela ukuphazamiseka kokusebenza kwamaphaphu kanye ne-thrombosis kubantu abane-asthma kanye nokwandisa ingozi yomdlavuza wesikhumba, wamaphaphu, wesinye kanye nowesisu (Olsson et al., 2010; Diggs et al., 2011). Izifundo zezilwane zikhombisile nokuthi ukuchayeka kwe-PAH kungaba nemiphumela emibi ekusebenzeni nasekuthuthukisweni kokuzala futhi kungabangela i-cataracts, ukulimala kwezinso nesibindi, kanye ne-jaundice. Imikhiqizo ehlukahlukene ye-PAH biotransformation efana nama-diols, ama-epoxide, ama-quinones kanye nama-free radicals (ama-cation) kuye kwabonakala sengathi kwakha ama-DNA adducts. Kuye kwabonakala ukuthi ama-adduct azinzile ashintsha imishini yokuphindaphinda i-DNA, kanti ama-adduct angazinzile angasusa ukungcola kwe-DNA (ikakhulukazi ibe yi-adenine futhi ngezinye izikhathi ibe yi-guanine); womabili angadala amaphutha aholela ekuguqukeni kwezakhi zofuzo (Schweigert et al. 2001). Ngaphezu kwalokho, ama-quinone (benzo-/pan-) angakhiqiza izinhlobo ze-oxygen ezisebenzayo (ROS), okubangela umonakalo obulalayo kwi-DNA nakwamanye ama-macromolecule, ngaleyo ndlela kuthinte ukusebenza/ukuphila kwezicubu (Ewa noDanuta 2017). Ukuchayeka njalo ekugxilweni okuphansi kwe-pyrene, i-biphenyl kanye ne-naphthalene kubikwe ukuthi kubangela umdlavuza ezilwaneni ezivivinywayo (Diggs et al. 2012). Ngenxa yobuthi bazo obubulalayo, ukuhlanzwa/ukususwa kwala ma-PAH ezindaweni ezithintekile/ezingcolisiwe kuyinto eza kuqala.
Kusetshenziswe izindlela ezahlukene zomzimba nezamakhemikhali ukususa ama-PAH ezindaweni/izindawo ezingcolile. Izinqubo ezifana nokushiswa, ukususa i-chlorination, ukushiswa kwe-UV, ukuqina, kanye nokukhishwa kwe-solvent kunezinkinga eziningi, okuhlanganisa ukwakheka kwemikhiqizo enobuthi, ubunzima benqubo, izinkinga zokuphepha kanye nokulawula, ukusebenza kahle okuphansi, kanye nezindleko eziphezulu. Kodwa-ke, ukubola kwamagciwane (okubizwa ngokuthi i-bioremediation) kuyindlela ehlukile ethembisayo ehilela ukusetshenziswa kwamagciwane ngendlela yamasiko noma amakoloni ahlanzekile. Uma kuqhathaniswa nezindlela zomzimba nezamakhemikhali, le nqubo inobungani nemvelo, ayihlaseli, iyabiza, futhi iyasimeme. Ukulungiswa kwamakhemikhali kungenziwa endaweni ethintekile (in situ) noma endaweni elungiselelwe ngokukhethekile (ex situ) ngakho-ke kubhekwa njengendlela yokulungisa eqhubekayo kunezindlela zendabuko zomzimba nezamakhemikhali (Juhasz noNaidu, 2000; Andreoni noGianfreda, 2007; Megharaj et al., 2011; Phale et al., 2020; Sarkar et al., 2020).
Ukuqonda izinyathelo ze-metabolism yamagciwane ezihilelekile ekonakalisweni kwezinto ezingcolisa amakhemikhali kunemiphumela emikhulu yesayensi nezomnotho ekusimeni kwemvelo kanye nemvelo. Amagremu alinganiselwa ku-2.1 × 1018 ekhabhoni (C) agcinwa ezidakeni nasezingxubeni zezinto eziphilayo (okungukuthi, uwoyela, igesi yemvelo, kanye namalahle, okungukuthi, amafutha angaphansi komhlaba) emhlabeni jikelele, okwenza umnikelo omkhulu emjikelezweni wekhabhoni womhlaba wonke. Kodwa-ke, ukuthuthuka okusheshayo kwezimboni, ukukhishwa kwamafutha angaphansi komhlaba, kanye nemisebenzi yabantu kuqeda la machibi ekhabhoni e-lithospheric, kukhipha cishe amagremu angu-5.5 × 1015 ekhabhoni engokwemvelo (njengokungcola) emkhathini minyaka yonke (Gonzalez-Gaya et al., 2019). Iningi lale khabhoni engokwemvelo lingena ezindaweni zemvelo zomhlaba nezasolwandle ngokuthuthwa, ukuthuthwa, kanye nokugeleza kwamanzi. Ngaphezu kwalokho, izinto ezintsha ezingcolisa ezenziwe ngezinto ezitholakala kumafutha angaphansi komhlaba, njengepulasitiki, ama-plasticizer kanye nama-plastic stabilizer (ama-phthalates nama-isomers awo), zingcolisa kakhulu izindawo zemvelo zasolwandle, inhlabathi kanye nezasemanzini kanye ne-biota yazo, ngaleyo ndlela zikhulisa izingozi zesimo sezulu somhlaba wonke. Izinhlobo ezahlukene ze-microplastics, i-nanoplastics, izingcezu zepulasitiki kanye nemikhiqizo yazo ye-monomer enobuthi etholakala ku-polyethylene terephthalate (PET) ziqoqene e-Pacific Ocean phakathi kweNyakatho Melika kanye ne-Southeast Asia, zakha i-“Great Pacific Garbage Patch”, zalimaza impilo yasolwandle (Newell et al., 2020). Izifundo zesayensi zibonise ukuthi akunakwenzeka ukususa ukungcola/imfucuza enjalo nganoma yiziphi izindlela zomzimba noma zamakhemikhali. Kulesi simo, ama-microorganism awusizo kakhulu yilawo akwazi ukuguqula ukungcola kube yi-carbon dioxide, amandla amakhemikhali kanye neminye imikhiqizo engeyona enobuthi ekugcineni engena kwezinye izinqubo zokujikeleza kwezakhamzimba (H, O, N, S, P, Fe, njll.). Ngakho-ke, ukuqonda i-microbial ecophysiology ye-aromatic pollutant mineralization kanye nokulawulwa kwayo kwemvelo kubalulekile ekuhloleni umjikelezo we-microbial carbon, isabelomali se-carbon net kanye nezingozi zesimo sezulu zesikhathi esizayo. Njengoba kunesidingo esiphuthumayo sokususa ama-compounds anjalo emvelweni, kuye kwavela izimboni ezahlukene ze-eco-reg ezigxile kubuchwepheshe obuhlanzekile. Ngaphandle kwalokho, ukwazisa amakhemikhali emfucuza/imfucuza yezimboni aqoqwe ezindaweni zemvelo (okungukuthi indlela yokulahla imfucuza ibe yingcebo) kubhekwa njengenye yezinsika zomnotho ojikelezayo kanye nezinhloso zentuthuko eqhubekayo (Close et al., 2012). Ngakho-ke, ukuqonda izici ze-metabolic, i-enzymatic kanye nezakhi zofuzo zalezi zindlela zokonakala ezingaba khona kubaluleke kakhulu ekususweni nasekulungisweni kwe-bioremediation okuphumelelayo kwalezo zinto ezingcolisayo ezinephunga elimnandi.
Phakathi kwezinto eziningi ezingcolisayo, sinaka kakhulu ama-PAH anesisindo esincane sama-molecule njenge-naphthalene kanye nama-naphthalene afakwe esikhundleni sawo. Lawa ma-compound ayizingxenye ezinkulu zamafutha atholakala ku-petroleum, amadayi endwangu, imikhiqizo yabathengi, izibulala-zinambuzane (ama-mothball kanye nezixosha izinambuzane), ama-plasticizer kanye nama-tannins futhi ngenxa yalokho asakazeke ezindaweni eziningi zemvelo (Preuss et al., 2003). Imibiko yakamuva iqokomisa ukuqongelela kwamazinga e-naphthalene ezindaweni ezimanzi, emanzini angaphansi komhlaba kanye nenhlabathi engaphansi komhlaba, izindawo ze-vadose kanye nemifula, okuphakamisa ukuqongelela kwayo endaweni ezungezile (Duttagupta et al., 2019, 2020). Ithebula 2 lifingqa izakhiwo ze-physicochemical, ukusetshenziswa kanye nemiphumela yezempilo ye-naphthalene kanye nezinto eziphuma kuyo. Uma kuqhathaniswa namanye ama-PAH anesisindo esiphezulu sama-molecule, i-naphthalene kanye nezinto eziphuma kuyo azinawo umoya, azincibiliki emanzini futhi zisakazeke kabanzi ezindaweni zemvelo, ngakho-ke zivame ukusetshenziswa njengezibonelo zesisekelo sokutadisha i-metabolism, izakhi zofuzo kanye nokuhlukahluka kwe-metabolic kwama-PAH. Inani elikhulu lama-microorganisms liyakwazi ukugaya i-naphthalene kanye nemikhiqizo yayo, futhi ulwazi oluphelele luyatholakala ngezindlela zabo ze-metabolic, ama-enzyme kanye nezici zokulawula (Mallick et al., 2011; Phale et al., 2019, 2020). Ngaphezu kwalokho, i-naphthalene kanye nemikhiqizo yayo ibizwa ngokuthi ama-prototype compounds okuhlola ukungcoliswa kwemvelo ngenxa yobuningi bayo obukhulu kanye nokutholakala kwayo. I-US Environmental Protection Agency ilinganisela ukuthi amazinga ajwayelekile e-naphthalene angama-5.19 μg nge-cubic meter ngayinye kusuka entuthwini kagwayi, ikakhulukazi ngenxa yokusha okungaphelele, kanye nama-7.8 kuya ku-46 μg kusuka entuthwini eseceleni, kuyilapho ukuchayeka ku-creosote kanye ne-naphthalene kuphakeme ngokuphindwe kayi-100 kuya ku-10,000 (Preuss et al. 2003). I-Naphthalene ikakhulukazi itholakale inobuthi bokuphefumula obuqondene nezinhlobo, isifunda, kanye nobulili kanye nomthelela womdlavuza. Ngokusekelwe ezifundweni zezilwane, i-International Agency for Research on Cancer (IARC) ihlukanise i-naphthalene “njengesifo esingabangela umdlavuza kubantu” (Iqembu 2B)1. Ukuchayeka kuma-naphthalene afakwe esikhundleni sawo, ikakhulukazi ngokuphefumula noma ngokuphathwa ngomlomo (ngomlomo), kubangela ukulimala kwezicubu zamaphaphu futhi kwandisa ukwanda kwezimila zamaphaphu kumagundane nasemagundwini (Uhlelo Lwezobuthi Lukazwelonke 2). Imiphumela emibi ifaka phakathi isicanucanu, ukuhlanza, ubuhlungu besisu, isifo sohudo, ikhanda elibuhlungu, ukudideka, ukujuluka okukhulu, umkhuhlane, i-tachycardia, njll. Ngakolunye uhlangothi, i-carbamate insecticide carbaryl (1-naphthyl N-methylcarbamate) ebikwe ukuthi inobuthi ezilwanyaneni ezingenamgogodla zasemanzini, ezilwanyaneni zasemanzini, ezinyosini zezinyosi nakubantu futhi iboniswe ukuthi ivimbela i-acetylcholinesterase ebangela ukukhubazeka (Smulders et al., 2003; Bulen and Distel, 2011). Ngakho-ke, ukuqonda izindlela zokuwohloka kwamagciwane, ukulawulwa kwezakhi zofuzo, ukusabela kwe-enzymatic kanye namaseli kubalulekile ekuthuthukiseni amasu okulungisa izinto eziphilayo ezindaweni ezingcolile.
Ithebula 2. Ulwazi oluningiliziwe mayelana nezakhiwo ze-physicochemical, ukusetshenziswa, izindlela zokuhlonza kanye nezifo ezihlobene ne-naphthalene kanye nezinto eziphuma kuyo.
Ezindaweni ezingcolile, ukungcola okunuka kamnandi okungathandi amanzi kanye nokungathandi amafutha kungabangela imiphumela ehlukahlukene yamaseli ku-microbiome yemvelo (umphakathi), njengokushintsha kokugeleza kwe-membrane, ukutholakala kwe-membrane, ukuvuvukala kwe-lipid bilayer, ukuphazamiseka kokudluliswa kwamandla (uchungechunge lokuthuthwa kwe-electron/amandla e-proton motive), kanye nomsebenzi wamaprotheni ahlobene ne-membrane (Sikkema et al., 1995). Ngaphezu kwalokho, ezinye izinto ezincibilikayo ezifana nama-catechol nama-quinones zikhiqiza izinhlobo ze-oxygen ezisebenzayo (i-ROS) futhi zakha ama-adducts ane-DNA namaprotheni (Penning et al., 1999). Ngakho-ke, ubuningi bamakhemikhali anjalo ezindaweni zemvelo bunengcindezi ekhethiwe emiphakathini yamagciwane ukuze ibe yizinto eziwohlokayo ezisebenza kahle emazingeni ahlukahlukene e-physiological, okuhlanganisa ukumuncwa/ukuthutha, ukuguqulwa kwangaphakathi kweseli, ukuhlanganiswa/ukusetshenziswa, kanye nokwahlukaniswa.
Ukusesha kwe-Ribosomal Database Project-II (RDP-II) kwembule ukuthi izinhlobo ezingama-bacteria ezingu-926 zihlukaniswe emasikweni ahlukene noma acebile angcoliswe yi-naphthalene noma izinto eziphuma kuyo. Iqembu le-Proteobacteria lalinabameleli abaningi kakhulu (n = 755), lilandelwa yi-Firmicutes (52), i-Bacteroidetes (43), i-Actinobacteria (39), i-Tenericutes (10), kanye namagciwane angahlukaniswanga (8) (Isithombe 2). Abameleli be-γ-Proteobacteria (Pseudomonadales kanye ne-Xanthomonadales) babusa wonke amaqembu angenayo i-Gram anokuqukethwe okuphezulu kwe-G+C (54%), kuyilapho i-Clostridiales kanye ne-Bacillales (30%) kwakungamaqembu angenayo i-Gram anokuqukethwe okuphansi kwe-G+C. Ama-Pseudomonas (inani elikhulu kunawo wonke, izinhlobo ezingu-338) kubikwe ukuthi akwazi ukonakalisa i-naphthalene kanye nezinto ezitholakala kuyo ze-methyl ezindaweni ezahlukene ezingcolisiwe (i-coal tar, i-petroleum, i-oyela engahluziwe, udaka, ukuchitheka kukawoyela, amanzi angcolile, imfucuza yezinto eziphilayo kanye nezindawo zokulahla udoti) kanye nasezindaweni eziphilayo eziphelele (umhlabathi, imifula, inhlabathi kanye namanzi angaphansi komhlaba) (Isithombe 2). Ngaphezu kwalokho, izifundo zokucebisa kanye nokuhlaziywa kwe-metagenomic kwezinye zalezi zifunda kwembule ukuthi izinhlobo ze-Legionella ne-Clostridium ezingakhuliswanga zingase zibe namandla okubola, okubonisa isidingo sokukhulisa la mabhaktheriya ukuze kufundwe izindlela ezintsha kanye nokuhlukahluka kwe-metabolic.
Isithombe 2. Ukuhlukahluka kwe-taxonomic kanye nokusatshalaliswa kwemvelo kwabameleli bamabhaktheriya ezindaweni ezingcoliswe yi-naphthalene kanye ne-naphthalene derivatives.
Phakathi kwezinhlobo ezahlukene ze-aromatic hydrocarbon-degrading microorganisms, eziningi zazo ziyakwazi ukonakalisa i-naphthalene njengomthombo owodwa wekhabhoni namandla. Ukulandelana kwezehlakalo ezihilelekile ekusetshenzisweni kwe-naphthalene kuye kwachazwa nge-Pseudomonas sp. (izinhlobo: NCIB 9816-4, G7, AK-5, PMD-1 kanye ne-CSV86), i-Pseudomonas stutzeri AN10, i-Pseudomonas fluorescens PC20 kanye nezinye izinhlobo (ND6 kanye ne-AS1) (Mahajan et al., 1994; Resnick et al., 1996; Annweiler et al., 2000; Basu et al., 2003; Dennis and Zylstra, 2004; Sota et al., 2006; I-Metabolism iqalwa yi-dioxygenase enezinto eziningi [naphthalene dioxygenase (NDO), i-ring hydroxylating dioxygenase] evuselela i-oxidation kwenye yezindandatho ze-naphthalene esebenzisa i-molecule oxygen njengenye i-substrate, iguqula i-naphthalene ibe yi-cis-naphthalenediol (Isithombe 3). I-Cis-dihydrodiol iguqulwa ibe yi-1,2-dihydroxynaphthalene yi- i-dehydrogenase. I-dioxygenase ehlukanisa indandatho, i-1,2-dihydroxynaphthalene dioxygenase (12DHNDO), iguqula i-1,2-dihydroxynaphthalene ibe yi-2-hydroxychromene-2-carboxylic acid. I-enzyme cis-trans isomerization ikhiqiza i-trans-o-hydroxybenzylidenepyruvate, ehlukaniswa yi-hydratase aldolase ibe yi-salicylic aldehyde kanye ne-pyruvate. I-organic acid pyruvate yayiyi-compound yokuqala ye-C3 ethathwe ku-naphthalene carbon skeleton futhi yaqondiswa endleleni ephakathi yekhabhoni. Ngaphezu kwalokho, i-NAD+-dependent salicylaldehyde dehydrogenase iguqula i-salicylaldehyde ibe yi-salicylic acid. I-metabolism kulesi sigaba ibizwa ngokuthi "indlela ephezulu" yokubola kwe-naphthalene. Le ndlela ivame kakhulu kumabhaktheriya amaningi abola i-naphthalene. Kodwa-ke, kunezimo ezimbalwa ezihlukile; isibonelo, ku-thermophilic Bacillus hamburgii 2, ukubola kwe-naphthalene kuqala yi-naphthalene. I-2,3-dioxygenase ukuze yakhe i-2,3-dihydroxynaphthalene (Annweiler et al., 2000).
Isithombe 3. Izindlela ze-naphthalene, i-methylnaphthalene, i-naphthoic acid, kanye nokuwohloka kwe-carbaryl. Izinombolo ezijikeleziwe zimele ama-enzyme abangela ukuguqulwa okulandelanayo kwe-naphthalene kanye nezinto eziphuma kuyo zibe imikhiqizo elandelayo. 1 — i-naphthalene dioxygenase (NDO); 2, i-cis-dihydrodiol dehydrogenase; 3, i-1,2-dihydroxynaphthalene dioxygenase; 4, i-2-hydroxychromene-2-carboxylic acid isomerase; 5, i-trans-O-hydroxybenzylidenepyruvate hydratase aldolase; 6, i-salicylaldehyde dehydrogenase; 7, i-salicylate 1-hydroxylase; 8, i-catechol 2,3-dioxygenase (C23DO); 9, i-2-hydroxymuconate semialdehyde dehydrogenase; 10, i-2-oxopent-4-enoate hydratase; 11, i-4-hydroxy-2-oxopentanoate aldolase; 12, i-acetaldehyde dehydrogenase; 13, i-catechol-1,2-dioxygenase (C12DO); 14, i-muconate cycloisomerase; 15, i-muconolactone delta-isomerase; 16, i-β-ketoadipatenollactone hydrolase; 17, i-β-ketoadipate succinyl-CoA transferase; 18, i-β-ketoadipate-CoA thiolase; 19, i-succinyl-CoA: i-acetyl-CoA succinyltransferase; 20, i-salicylate 5-hydroxylase; 21 – i-gentisate 1,2-dioxygenase (GDO); 22, i-maleylpyruvate isomerase; 23, i-fumarylpyruvate hydrolase; 24, i-methylnaphthalene hydroxylase (NDO); 25, i-hydroxymethylnaphthalene dehydrogenase; 26, i-naphthaldehyde dehydrogenase; 27, i-3-formylsalicylic acid oxidase; 28, i-hydroxyisophthalate decarboxylase; 29, i-carbaryl hydrolase (CH); 30, i-1-naphthol-2-hydroxylase.
Kuye ngokuthi i-organism kanye nokwakheka kwayo kwezakhi zofuzo, i-salicylic acid ephumayo iyaqhubeka nokuguqulwa ibe yindlela ye-catechol kusetshenziswa i-salicylate 1-hydroxylase (S1H) noma ngendlela ye-gentisate kusetshenziswa i-salicylate 5-hydroxylase (S5H) (Isithombe 3). Njengoba i-salicylic acid iyindlela ephakathi nendawo enkulu ekusetshenzisweni kwe-naphthalene (indlela ephezulu), izinyathelo ezivela ku-salicylic acid kuya ku-TCA intermediate zivame ukubizwa ngokuthi indlela engezansi, futhi izakhi zofuzo zihlelwe zaba yi-operon eyodwa. Kuvamile ukubona ukuthi izakhi zofuzo eziku-operon (nah) kanye ne-operon (sal) yendlela engezansi zilawulwa yizici ezivamile zokulawula; isibonelo, i-NahR kanye ne-salicylic acid zisebenza njengezikhuthazi, okuvumela ama-operon womabili ukuthi aguqule ngokuphelele i-naphthalene (Phale et al., 2019, 2020).
Ngaphezu kwalokho, i-catechol ihlukaniswa ngokujikeleza ibe yi-2-hydroxymuconate semialdehyde ngendlela ye-meta yi-catechol 2,3-dioxygenase (C23DO) (Yen et al., 1988) bese ihlanganiswa nge-2-hydroxymuconate semialdehyde hydrolase ukuze yakhe i-2-hydroxypent-2,4-dienoic acid. I-2-hydroxypent-2,4-dienoate ibe isiguqulwa ibe yi-pyruvate kanye ne-acetaldehyde yi-hydratase (2-oxopent-4-enoate hydratase) kanye ne-aldolase (4-hydroxy-2-oxopentanoate aldolase) bese ingena endleleni ephakathi yekhabhoni (Isithombe 3). Ngaphandle kwalokho, i-catechol ihlukaniswa ngokujikeleza ibe yi-cis,cis-muconate ngendlela ye-ortho yi-catechol 1,2-oxygenase (C12DO). I-Muconate cycloisomerase, i-muconolactone isomerase, kanye ne-β-ketoadipate-nollactone hydrolase ziguqula i-cis, cis-muconate ibe yi-3-oxoadipate, engena endleleni ephakathi yekhabhoni nge-succinyl-CoA kanye ne-acetyl-CoA (Nozaki et al., 1968) (Isithombe 3).
Endleleni ye-gentisate (2,5-dihydroxybenzoate), indandatho enuka kamnandi ihlukaniswa yi-gentisate 1,2-dioxygenase (GDO) ukuze kwakheke i-maleylpyruvate. Lo mkhiqizo ungafakwa ngqo ku-hydrolyzed ukuze kube yi-pyruvate kanye ne-malate, noma ungafakwa i-isomer ukuze kwakheke i-fumarylpyruvate, engabe isifakwa ku-hydrolyzed ukuze kube yi-pyruvate kanye ne-fumarate (Larkin and Day, 1986). Ukukhethwa kwendlela ehlukile kuye kwabonwa kokubili kumagciwane e-Gram-negative kanye ne-Gram-positive emazingeni e-biochemical kanye nezakhi zofuzo (Morawski et al., 1997; Whyte et al., 1997). Amagciwane e-Gram-negative (Pseudomonas) akhetha ukusebenzisa i-salicylic acid, okuyimbangela ye-naphthalene metabolism, eyisusa i-carboxylating ibe yi-catechol isebenzisa i-salicylate 1-hydroxylase (Gibson and Subramanian, 1984). Ngakolunye uhlangothi, kubhaktheriya one-Gram-positive (Rhodococcus), i-salicylate 5-hydroxylase iguqula i-salicylic acid ibe yi-gentisic acid, kanti i-salicylic acid ayinawo umphumela wokungenisa amandla ekubhalweni kwezakhi zofuzo ze-naphthalene (Grund et al., 1992) (Isithombe 3).
Kubikwe ukuthi izinhlobo ezifana ne-Pseudomonas CSV86, i-Oceanobacterium NCE312, i-Marinhomonas naphthotrophicus, i-Sphingomonas paucimobilis 2322, i-Vibrio cyclotrophus, i-Pseudomonas fluorescens LP6a, izinhlobo ze-Pseudomonas kanye ne-Mycobacterium zingalimaza i-monomethylnaphthalene noma i-dimethylnaphthalene (Dean-Raymond no-Bartha, 1975; Cane no-Williams, 1982; Mahajan et al., 1994; Dutta et al., 1998; Hedlund et al., 1999). Phakathi kwazo, indlela yokuwohloka kwe-1-methylnaphthalene kanye ne-2-methylnaphthalene ye-Pseudomonas sp. CSV86 ifundwe ngokucacile emazingeni e-biochemical kanye ne-enzymatic (Mahajan et al., 1994). I-1-Methylnaphthalene iguqulwa ngezindlela ezimbili. Okokuqala, indandatho enuka kamnandi i-hydroxylated (indandatho engashintshwanga ye-methylnaphthalene) ukuze yakhe i-cis-1,2-dihydroxy-1,2-dihydro-8-methylnaphthalene, ephinde i-oxidized ibe yi-methyl salicylate kanye ne-methylcatechol, bese ingena endleleni ephakathi yekhabhoni ngemva kokuqhekeka kwendandatho (Isithombe 3). Le ndlela ibizwa ngokuthi "indlela yomthombo wekhabhoni". Endleleni yesibili "yokususa ubuthi", iqembu le-methyl lingaphinde li-hydroxylated yi-NDO ukuze lenze i-1-hydroxymethylnaphthalene, ephinde i-oxidized ibe yi-1-naphthoic acid bese ikhishwa endaweni yokukhulisa njengomkhiqizo ongapheli. Izifundo zibonise ukuthi uhlobo lwe-CSV86 alukwazi ukukhula ku-1- kanye ne-2-naphthoic acid njengomthombo wekhabhoni kanye namandla kuphela, okuqinisekisa indlela yalo yokususa ubuthi (Mahajan et al., 1994; Basu et al., 2003). Ku-2-methylnaphthalene, iqembu le-methyl lidlula ku-hydroxylation yi-hydroxylase ukuze kwakheke i-2-hydroxymethylnaphthalene. Ngaphezu kwalokho, indandatho engashintshiwe yendandatho ye-naphthalene idlula ku-hydroxylation yendandatho ukuze kwakheke i-dihydrodiol, efakwa ku-4-hydroxymethylcatechol ochungechungeni lwezimpendulo ezibangelwa yi-enzyme futhi ingena endleleni ephakathi yekhabhoni ngendlela ye-meta-ring cleavage. Ngokufanayo, i-S. paucimobilis 2322 kubikwe ukuthi isebenzisa i-NDO ku-hydroxylate 2-methylnaphthalene, efakwa ku-oxidized ukuze kwakheke i-methyl salicylate kanye ne-methylcatechol (Dutta et al., 1998).
Ama-asidi e-naphthoic (afakwe esikhundleni/angafakwa esikhundleni) ayimikhiqizo ephuma ekususeni ubuthi/ukuguqulwa kwe-bio eyakheka ngesikhathi sokuwohloka kwe-methylnaphthalene, i-phenanthrene kanye ne-anthracene bese ikhishwa endaweni yokulima esetshenzisiwe. Kubikwe ukuthi i-Stenotrophomonas maltophilia CSV89 ehlukanisa inhlabathi iyakwazi ukugaya i-1-naphthoic acid njengomthombo wekhabhoni (Phale et al., 1995). I-metabolism iqala nge-dihydroxylation yendandatho enuka kamnandi ukuze yakhe i-1,2-dihydroxy-8-carboxynaphthalene. I-diol ephumayo i-oxidized ibe yi-catechol nge-2-hydroxy-3-carboxybenzylidenepyruvate, i-3-formylsalicylic acid, i-2-hydroxyisophthalic acid kanye ne-salicylic acid futhi ingena endleleni ephakathi yekhabhoni ngendlela ye-meta-ring cleavage (Isithombe 3).
I-Carbaryl iyisibulala-zinambuzane se-naphthyl carbamate. Kusukela ngeNguquko Eluhlaza eNdiya ngawo-1970, ukusetshenziswa komanyolo wamakhemikhali kanye nezibulala-zinambuzane kuholele ekwandeni kokukhishwa kwe-polycyclic aromatic hydrocarbon (PAH) okuvela emithonjeni yezolimo engekho endaweni (Pingali, 2012; Duttagupta et al., 2020). Kulinganiselwa ukuthi ama-55% (amahektha angu-85,722,000) enhlabathi yonke yezitshalo eNdiya aphathwa ngezibulala-zinambuzane zamakhemikhali. Eminyakeni emihlanu edlule (2015-2020), umkhakha wezolimo waseNdiya usebenzise isilinganiso samathani angu-55,000 kuya ku-60,000 wezibulala-zinambuzane minyaka yonke (uMnyango Wezokubambisana Nezenhlalakahle Yabalimi, uMnyango Wezolimo, Uhulumeni waseNdiya, Agasti 2020). Emathafeni aseGangetic asenyakatho naphakathi (izifundazwe ezinenani labantu abaningi kanye nenani labantu), ukusetshenziswa kwezibulala-zinambuzane ezitshalweni kusakazeke kakhulu, kanti izibulala-zinambuzane zidlangile. I-Carbaryl (1-naphthyl-N-methylcarbamate) iyi-insecticide ye-carbamate ene-spectrum ebanzi, enobuthi obuphakathi kuya kobukhulu esetshenziswa kwezolimo zaseNdiya ngesilinganiso esimaphakathi samathani ayi-100-110. Ivame ukuthengiswa ngaphansi kwegama lokuhweba elithi Sevin futhi isetshenziselwa ukulawula izinambuzane (ama-aphid, izintuthwane zomlilo, izinambuzane, izimbuzane, izicabucabu nezinye izinambuzane eziningi zangaphandle) ezithinta izitshalo ezahlukahlukene (ummbila, ubhontshisi, ukotini, izithelo nemifino). Amanye ama-microorganisms afana ne-Pseudomonas (NCIB 12042, 12043, C4, C5, C6, C7, Pseudomonas putida XWY-1), Rhodococcus (NCIB 12038), Sphingobacterium spp. (CF06), Burkholderia (C3), Micrococcus kanye ne-Arthrobacter nawo angasetshenziswa ukulawula ezinye izinambuzane. Kubikwe ukuthi i-RC100 ingalimaza i-carbaryl (Larkin and Day, 1986; Chapalamadugu and Chaudhry, 1991; Hayatsu et al., 1999; Swetha and Phale, 2005; Trivedi et al., 2017). Indlela yokuwohloka kwe-carbaryl ifundwe kabanzi emazingeni e-biochemical, enzymatic kanye nezakhi zofuzo ezingxenyeni zenhlabathi ze-Pseudomonas sp. Strains C4, C5 kanye ne-C6 (Swetha and Phale, 2005; Trivedi et al., 2016) (Isithombe 3). Indlela ye-metabolic iqala nge-hydrolysis yesibopho se-ester yi-carbaryl hydrolase (CH) ukuze yakhe i-1-naphthol, i-methylamine kanye ne-carbon dioxide. I-1-naphthol ibe isiguqulwa ibe yi-1,2-dihydroxynaphthalene yi-1-naphthol hydroxylase (1-NH), ephinde isetshenziswe ngendlela ephakathi yekhabhoni nge-salicylate kanye ne-gentisate. Amanye amabhaktheriya aqeda i-carbaryl abikwe ukuthi ayayiguqula ibe yi-salicylic acid ngokuqhekeka kwendandatho ye-catechol ortho (Larkin and Day, 1986; Chapalamadugu and Chaudhry, 1991). Okuphawulekayo ukuthi amabhaktheriya aqeda i-naphthalene ngokuyinhloko ayayiguqula i-salicylic acid nge-catechol, kanti amabhaktheriya aqeda i-carbaryl akhetha ukuyiguqula ibe yi-salicylic acid ngendlela ye-gentisate.
I-Naphthalenesulfonic acid/disulfonic acid kanye ne-naphthylaminesulfonic acid derivatives zingasetshenziswa njengezinto ezisiza ekukhiqizeni amadayi e-azo, ama-wetting agents, ama-dispersants, njll. Nakuba lawa ma-compounds enobuthi obuphansi kubantu, ukuhlolwa kwe-cytotoxicity kukhombisile ukuthi ayabulala izinhlanzi, i-daphnia kanye ne-algae (Greim et al., 1994). Abameleli bohlobo lwe-Pseudomonas (izinhlobo ze-A3, C22) kubikwe ukuthi baqala i-metabolism nge-hydroxylation ephindwe kabili yendandatho e-aromatic equkethe iqembu le-sulfonic acid ukuze yakhe i-dihydrodiol, eguqulwa ibe yi-1,2-dihydroxynaphthalene ngokuqhekeka okuzenzakalelayo kweqembu le-sulfite (Brilon et al., 1981). I-1,2-dihydroxynaphthalene ephumelayo ihlanganiswa ngendlela ye-naphthalene yakudala, okungukuthi, indlela ye-catechol noma ye-gentisate (Isithombe 4). Kuye kwaboniswa ukuthi i-aminonaphthalenesulfonic acid kanye ne-hydroxynaphthalenesulfonic acid zingawohloka ngokuphelele yi-consortia exubile yamagciwane enezindlela ezihambisanayo ze-catabolic (Nortemann et al., 1986). Kuye kwaboniswa ukuthi ilungu elilodwa le-consortium lisusa i-aminonaphthalenesulfonic acid noma i-hydroxynaphthalenesulfonic acid nge-1,2-dioxygenation, kuyilapho i-aminosalicylate noma i-hydroxysalicylate ikhishwa endaweni yokukhulisa njenge-metabolite efile futhi kamuva ithathwa ngamanye amalungu e-consortium. I-Naphthalenedisulfonic acid i-polar kodwa ayiboli kahle futhi ngenxa yalokho ingaguqulwa ngezindlela ezahlukene. I-desulfurization yokuqala yenzeka ngesikhathi se-regioselective dihydroxylation yendandatho ye-aromatic kanye neqembu le-sulfonic acid; i-desulfurization yesibili yenzeka ngesikhathi se-hydroxylation ye-5-sulfosalicylic acid yi-salicylic acid 5-hydroxylase ukwakha i-gentisic acid, engena endleleni ephakathi yekhabhoni (Brilon et al., 1981) (Isithombe 4). Ama-enzyme abangela ukuwohloka kwe-naphthalene nawo abangela i-metabolism ye-naphthalene sulfonate (Brilon et al., 1981; Keck et al., 2006).
Isithombe 4. Izindlela ze-metabolic zokuwohloka kwe-naphthalene sulfonate. Izinombolo ezingaphakathi kwezindilinga zimele ama-enzyme abangela i-naphthyl sulfonate metabolism, afana/afana nama-enzyme achazwe ku-FIG. 3.
Ama-PAH anesisindo esiphansi sama-molecule (ama-LMW-PAH) ayancishiswa, awangeni emanzini futhi awancibiliki kahle, ngakho-ke awakwazi ukuwohloka/ukubola ngokwemvelo. Kodwa-ke, ama-microorganisms e-aerobic ayakwazi ukuyixuba ngokumunca i-oxygen yama-molecule (O2). Lawa ma-enzyme ikakhulukazi angaphansi kwesigaba sama-oxidoreductase futhi angenza ukusabela okuhlukahlukene njenge-aromatic ring hydroxylation (i-mono- noma i-dihydroxylation), i-dehydrogenation kanye ne-aromatic ring cleavage. Imikhiqizo etholakala kulezi zindlela isesimweni esiphezulu se-oxidation futhi ixutshwa kalula ngendlela ephakathi yekhabhoni (Phale et al., 2020). Ama-enzyme asendleleni yokubola kubikwe ukuthi awakwazi ukucutshungulwa. Umsebenzi wala ma-enzyme uphansi kakhulu noma awubalulekile lapho amaseli ekhuliswa emithonjeni elula yekhabhoni njenge-glucose noma ama-organic acid. Ithebula 3 lifingqa ama-enzyme ahlukahlukene (ama-oxygenase, ama-hydrolase, ama-dehydrogenase, ama-oxidases, njll.) ahilelekile ekucutshungulweni kwe-naphthalene kanye nezinto eziphuma kuyo.
Ithebula 3. Izici ze-biochemical zama-enzyme abangela ukuwohloka kwe-naphthalene kanye nezinto eziphuma kuyo.
Izifundo ze-Radioisotope (18O2) zikhombisile ukuthi ukufakwa kwe-molecule O2 emasongweni e-aromatic yi-oxygenases kuyisinyathelo esibaluleke kakhulu ekuqaliseni ukubola okuqhubekayo kwe-compound (Hayaishi et al., 1955; Mason et al., 1955). Ukufakwa kwe-athomu eyodwa ye-oxygen (O) kusuka ku-molecule oxygen (O2) kuya ku-substrate kuqaliswa yi-endogenous noma i-exogenous monooxygenases (ebizwa nangokuthi i-hydroxylases). Elinye i-athomu ye-oxygen lincishiswa libe ngamanzi. Ama-exogenous monooxygenases ancishiswa yi-flavin nge-NADH noma i-NADPH, kanti kuma-endomonooxygenases i-flavin incishiswa yi-substrate. Indawo ye-hydroxylation iphumela ekuhlukeni ekwakhekeni komkhiqizo. Isibonelo, i-salicylate 1-hydroxylase hydroxylates salicylic acid endaweni ye-C1, yakha i-catechol. Ngakolunye uhlangothi, i-salicylate 5-hydroxylase enezingxenye eziningi (equkethe ama-reductase, i-ferredoxin, kanye nama-subunit e-oxygenase) i-hydroxylates i-salicylic acid endaweni ye-C5, yakha i-gentisic acid (Yamamoto et al., 1965).
Ama-Dioxygenase afaka ama-athomu amabili e-O2 ku-substrate. Kuye ngemikhiqizo eyakhiwe, ahlukaniswe ngama-ring hydroxylating dioxygenase kanye nama-ring cleaving dioxygenase. Ama-ring hydroxylating dioxygenase aguqula ama-aromatic substrates abe yi-cis-dihydrodiols (isb., i-naphthalene) futhi asakazeke kakhulu phakathi kwamagciwane. Kuze kube manje, kuye kwabonakala ukuthi izinto eziphilayo eziqukethe ama-ring hydroxylating dioxygenase ziyakwazi ukukhula emithonjeni eyahlukene ye-aromatic carbon, futhi lawa ma-enzyme ahlukaniswa njenge-NDO (naphthalene), i-toluene dioxygenase (TDO, toluene), kanye ne-biphenyl dioxygenase (BPDO, biphenyl). Kokubili i-NDO kanye ne-BPDO kungavuselela i-double oxidation kanye ne-side chain hydroxylation yama-hydrocarbon ahlukahlukene e-polycyclic aromatic (i-toluene, i-nitrotoluene, i-xylene, i-ethylbenzene, i-naphthalene, i-biphenyl, i-fluorene, i-indole, i-methylnaphthalene, i-naphthalenesulfonate, i-phenanthrene, i-anthracene, i-acetophenone, njll.) (Boyd noSheldrake, 1998; Phale et al., 2020). I-NDO uhlelo olunezingxenye eziningi oluqukethe i-oxidoreductase, i-ferredoxin, kanye nengxenye esebenzayo equkethe i-oxygenase (Gibson no-Subramanian, 1984; Resnick et al., 1996). Iyunithi ye-catalytic ye-NDO iqukethe i-subunit enkulu ye-α kanye ne-subunit encane ye-β ehlelwe ngendlela ye-α3β3. I-NDO ingeyomndeni omkhulu wama-oxygenase kanti i-α-subunit yayo iqukethe indawo ye-Rieske [2Fe-2S] kanye ne-mononuclear non-heme iron, enquma ukucaciswa kwe-substrate ye-NDO (Parales et al., 1998). Ngokuvamile, kumjikelezo owodwa we-catalytic, ama-electron amabili avela ekunciphiseni i-pyridine nucleotide adluliselwa kwi-Fe(II) ion endaweni esebenzayo nge-reductase, i-ferredoxin kanye nesayithi le-Rieske. Ama-reducing equivalents avuselela i-molecule oxygen, okuyisidingo se-substrate dihydroxylation (Ferraro et al., 2005). Kuze kube manje, ama-NDO ambalwa kuphela ahlanziwe futhi achazwa ngokuningiliziwe kusuka ezinhlotsheni ezahlukene futhi ukulawulwa kwezakhi zofuzo kwezindlela ezihilelekile ekuwohlokeni kwe-naphthalene kuye kwafundwa ngokuningiliziwe (Resnick et al., 1996; Parales et al., 1998; Karlsson et al., 2003). Ama-dioxygenase ahlukanisa indandatho (ama-enzyme e-endo- noma i-ortho-ring-cleaving kanye nama-enzyme e-exodiol noma i-meta-ring-cleaving) asebenza kuma-compound aromatic ahlanganiswe yi-hydroxylated. Isibonelo, i-ortho-ring-cleaving dioxygenase yi-catechol-1,2-dioxygenase, kanti i-meta-ring-cleaving dioxygenase yi-catechol-2,3-dioxygenase (Kojima et al., 1961; Nozaki et al., 1968). Ngaphezu kwama-oxygenase ahlukahlukene, kukhona nama-dehydrogenase ahlukahlukene abangela ukususwa kwe-hydrogen kwama-dihydrodiols aromatic, ama-alcohols nama-aldehydes kanye nokusebenzisa i-NAD+/NADP+ njengama-electron acceptors, amanye ama-enzyme abalulekile ahilelekile ekusetshenzisweni kwe-metabolism (Gibson and Subramanian, 1984; Shaw and Harayama, 1990; Fahle et al., 2020).
Ama-enzyme afana nama-hydrolase (ama-esterase, ama-amidase) ayisigaba sesibili esibalulekile sama-enzyme asebenzisa amanzi ukuhlukanisa izibopho ze-covalent futhi abonise ukucaciswa okubanzi kwe-substrate. I-Carbaryl hydrolase namanye ama-hydrolase abhekwa njengezingxenye ze-periplasm (i-transmembrane) kumalungu ebhaktheriya elinge-Gram (Kamini et al., 2018). I-Carbaryl inokuxhumana kwe-amide kanye ne-ester; ngakho-ke, ingafakwa i-hydrolyzed yi-esterase noma i-amidase ukuze yakhe i-1-naphthol. I-Carbaryl in Rhizobium rhizobium strain AC10023 kanye ne-Arthrobacter strain RC100 kubikwe ukuthi isebenza njenge-esterase kanye ne-amidase, ngokulandelana. I-Carbaryl in Arthrobacter strain RC100 nayo isebenza njenge-amidase. I-RC100 ikhonjiswe ukuthi i-hydrolyze izibulala-zinambuzane ezine ze-N-methylcarbamate class ezifana ne-carbaryl, i-methomyl, i-mefenamic acid kanye ne-XMC (Hayaatsu et al., 2001). Kwabikwa ukuthi i-CH ku-Pseudomonas sp. C5pp ingasebenza ku-carbaryl (umsebenzi we-100%) kanye ne-1-naphthyl acetate (umsebenzi we-36%), kodwa hhayi ku-1-naphthylacetamide, okubonisa ukuthi iyi-esterase (Trivesi et al., 2016).
Izifundo ze-biochemical, amaphethini okulawula ama-enzyme, kanye nokuhlaziywa kwezakhi zofuzo kubonise ukuthi izakhi zofuzo zokuwohloka kwe-naphthalene zakhiwa amayunithi amabili okulawula angena ngaphakathi noma “ama-operon”: i-nah (“indlela ephezulu”, eguqula i-naphthalene ibe yi-salicylic acid) kanye ne-sal (“indlela ephansi”, eguqula i-salicylic acid ibe yindlela ephakathi yekhabhoni nge-catechol). I-Salicylic acid kanye nama-analogue ayo angasebenza njengabashukumisi (Shamsuzzaman noBarnsley, 1974). Lapho kukhona i-glucose noma ama-organic acid, i-operon iyacindezelwa. Isithombe 5 sibonisa ukuhlelwa okuphelele kwezakhi zofuzo kokuwohloka kwe-naphthalene (ngesimo se-operon). Izinhlobo/izinhlobo eziningana eziqanjwe ngegama lezakhi zofuzo ze-nah (ndo/pah/dox) ziye zachazwa futhi zatholakala zine-homology ephezulu yokulandelana (90%) phakathi kwazo zonke izinhlobo ze-Pseudomonas (Abbasian et al., 2016). Izakhi zofuzo zendlela ephezulu ye-naphthalene ngokuvamile zazihlelwe ngokulandelana okuvumelanayo njengoba kuboniswe ku-Figure 5A. Esinye isakhi sofuzo, i-nahQ, naso sabikwa ukuthi sihilelekile ekusetshenzisweni kwe-naphthalene futhi sasivame ukutholakala phakathi kwe-nahC ne-nahE, kodwa umsebenzi waso wangempela usazocaciswa. Ngokufanayo, isakhi sofuzo se-nahY, esibangela i-chemotaxis ezwela i-naphthalene, satholakala ekugcineni kwe-nah operon kwamanye amalungu. Ku-Ralstonia sp., isakhi sofuzo se-U2 esifaka i-glutathione S-transferase (gsh) satholakala sitholakala phakathi kwe-nahAa ne-nahAb kodwa asizange sithinte izici zokusetshenziswa kwe-naphthalene (Zylstra et al., 1997).
Isithombe 5. Ukuhleleka kwezakhi zofuzo kanye nokwehlukahlukana okubonwe ngesikhathi sokuwohloka kwe-naphthalene phakathi kwezinhlobo zamabhaktheriya; (A) Indlela ephezulu ye-naphthalene, ukushintshwa kwe-naphthalene ibe yi-salicylic acid; (B) Indlela ephansi ye-naphthalene, i-salicylic acid nge-catechol iye endleleni ephakathi yekhabhoni; (C) i-salicylic acid nge-gentisate iye endleleni ephakathi yekhabhoni.
"Indlela engezansi" (i-sal operon) ngokuvamile iqukethe i-nahGTHINLMOKJ futhi iguqula i-salicylate ibe yi-pyruvate kanye ne-acetaldehyde ngendlela ye-catechol metaring cleavage. I-nahG gene (efaka i-salicylate hydroxylase) itholakale igcinwe ekugcineni kwe-operon (Isithombe 5B). Uma kuqhathaniswa nezinye izinhlobo ze-naphthalene-degrading, ku-P. putida CSV86 ama-nah kanye nama-sal operon ahlangene futhi ahlobene kakhulu (cishe ama-kb angu-7.5). Kwamanye amabhaktheriya e-Gram-negative, njenge-Ralstonia sp. U2, i-Polaromonas naphthalenivorans CJ2, kanye ne-P. putida AK5, i-naphthalene iguqulwa ibe yi-metabolite ye-carbon ephakathi ngendlela ye-gentisate (ngendlela ye-sgp/nag operon). Ikhasethi yezakhi zofuzo ngokuvamile imelelwa ngesimo se-nagAaGHabAcAdBFCQEDJI, lapho i-nagR (efaka ikhodi kumlawuli wohlobo lwe-LysR) itholakala ekugcineni okuphezulu (Isithombe 5C).
I-Carbaryl ingena emjikelezweni wekhabhoni ephakathi ngokusebenzisa i-metabolism ye-1-naphthol, i-1,2-dihydroxynaphthalene, i-salicylic acid, kanye ne-gentisic acid (Isithombe 3). Ngokusekelwe ezifundweni zezakhi zofuzo kanye ne-metabolic, kuye kwaphakanyiswa ukuthi le ndlela ihlukaniswe ibe “phezulu” (ukuguqulwa kwe-carbaryl ibe yi-salicylic acid), “phakathi” (ukuguqulwa kwe-salicylic acid ibe yi-gentisic acid), kanye “phansi” (ukuguqulwa kwe-gentisic acid ibe yi-central carbon pathway intermediates) (Singh et al., 2013). Ukuhlaziywa kwe-genomic kwe-C5pp (supercontig A, 76.3 kb) kwembule ukuthi i-mcbACBDEF gene ihilelekile ekuguqulweni kwe-carbaryl ibe yi-salicylic acid, kulandelwe yi-mcbIJKL ekuguqulweni kwe-salicylic acid ibe yi-gentisic acid, kanye ne-mcbOQP ekuguqulweni kwe-gentisic acid ibe yi-central carbon intermediates (i-fumarate kanye ne-pyruvate, i-Trivedi et al., 2016) (Isithombe 6).
Kubikwe ukuthi ama-enzyme ahilelekile ekuwohlokeni kwama-hydrocarbon aromatic (kufaka phakathi i-naphthalene ne-salicylic acid) angabangelwa yizakhi ezihambisanayo futhi avinjelwe imithombo elula yekhabhoni efana ne-glucose noma ama-organic acid (Shingler, 2003; Phale et al., 2019, 2020). Phakathi kwezindlela ezahlukahlukene ze-metabolic ze-naphthalene kanye ne-derivatives yayo, izici zokulawula ze-naphthalene ne-carbaryl ziye zafundwa ngezinga elithile. Ku-naphthalene, izakhi zofuzo kokubili ezindleleni eziphezulu nezingezansi zilawulwa yi-NahR, i-LysR-type trans-acting positive regulator. Iyadingeka ekuqalisweni kwezakhi zofuzo ze-nah yi-salicylic acid kanye nokubonakaliswa kwayo kwezinga eliphezulu okulandelayo (Yen noGunsalus, 1982). Ngaphezu kwalokho, izifundo zibonise ukuthi i-integrative host factor (IHF) kanye ne-XylR (sigma 54-dependent transcriptional regulator) nazo zibalulekile ekusebenzeni kwezakhi zofuzo ekusetshenzisweni kwezakhi zofuzo ekusetshenzisweni kwe-naphthalene (Ramos et al., 1997). Izifundo zibonise ukuthi ama-enzyme omgudu wokuvula i-catechol meta-ring, okuyi-catechol 2,3-dioxygenase, akhiqizwa lapho kukhona i-naphthalene kanye/noma i-salicylic acid (Basu et al., 2006). Izifundo zibonise ukuthi ama-enzyme omgudu wokuvula i-catechol ortho-ring, okuyi-catechol 1,2-dioxygenase, akhiqizwa lapho kukhona i-benzoic acid kanye ne-cis,cis-muconate (Parsek et al., 1994; Tover et al., 2001).
Kuhlobo lwe-C5pp, izakhi zofuzo ezinhlanu, i-mcbG, i-mcbH, i-mcbN, i-mcbR kanye ne-mcbS, zibhala ama-control angaphansi komndeni we-LysR/TetR wabalawuli be-transcriptional abaphethe ukulawula ukubola kwe-carbaryl. Izakhi zofuzo ezifana ne-mcbG zitholakale zihlobene kakhulu ne-LysR-type regulator PhnS (58% amino acid identity) ehilelekile ekusetshenzisweni kwe-phenanthrene ku-Burkholderia RP00725 (Trivesi et al., 2016). Izakhi zofuzo ze-mcbH zitholakale zihilelekile endleleni ephakathi (ukuguqulwa kwe-salicylic acid ibe yi-gentisic acid) futhi zingaphansi kwe-LysR-type transcriptional regulator NagR/DntR/NahR ku-Pseudomonas nase-Burkholderia. Amalungu alo mndeni abikwa ukuthi aqaphela i-salicylic acid njenge-molecule ethile ye-effector yokungenisa izakhi zofuzo zokubola. Ngakolunye uhlangothi, izakhi zofuzo ezintathu, i-mcbN, i-mcbR kanye ne-mcbS, ezingaphansi kwe-LysR kanye ne-TetR type transcriptional regulators, zitholakale endleleni engezansi (ama-metabolites e-gentisate-central carbon pathway).
Kuma-prokaryotes, izinqubo zokudlulisa izakhi zofuzo ezivundlile (ukutholwa, ukushintshaniswa, noma ukudluliselwa) ngama-plasmid, ama-transposon, ama-prophage, iziqhingi ze-genomic, kanye nezinto ezihlanganisiwe (i-ICE) ziyizimbangela ezinkulu ze-plasticity kuma-genome ebhaktheriya, okuholela ekuzuzeni noma ekulahlekelweni kwemisebenzi/izici ezithile. Ivumela amabhaktheriya ukuthi azivumelanise ngokushesha nezimo ezahlukene zemvelo, enikeza izinzuzo ezingaba khona ze-metabolic eziguquguqukayo kumnikazi, njengokuwohloka kwama-compounds aromatic. Izinguquko ze-metabolic zivame ukufezwa ngokulungiswa kahle kwama-operon okuwohloka, izindlela zawo zokulawula, kanye nokucaciswa kwama-enzyme, okusiza ukuwohloka kobubanzi obubanzi bama-compounds aromatic (Nojiri et al., 2004; Phale et al., 2019, 2020). Ama-cassette ezakhi zofuzo zokuwohloka kwe-naphthalene atholakale etholakala ezintweni ezahlukahlukene ezihambayo njenge-plasmids (ezihlanganisiwe nezingezona ezihlanganisiwe), ama-transposon, ama-genome, ama-ICE, kanye nokuhlanganiswa kwezinhlobo ezahlukene zamabhaktheriya (Isithombe 5). Ku-Pseudomonas G7, ama-nah kanye nama-sal operons e-plasmid NAH7 abhalwe ngendlela efanayo futhi ayingxenye ye-transposon enephutha edinga i-transposase Tn4653 ukuze ikwazi ukuhamba (Sota et al., 2006). Ku-Pseudomonas strain NCIB9816-4, i-gene itholakale ku-conjugative plasmid pDTG1 njengama-operons amabili (cishe ahlukaniswe ngama-kb angu-15) abhalwe ngezindlela ezihlukile (Dennis noZylstra, 2004). Ku-Pseudomonas putida strain AK5, i-non-conjugative plasmid pAK5 ibhala i-enzyme ebangela ukuwohloka kwe-naphthalene ngendlela ye-gentisate (Izmalkova et al., 2013). Kuhlobo lwe-Pseudomonas PMD-1, i-nah operon itholakala ku-chromosome, kanti i-sal operon itholakala ku-conjugative plasmid pMWD-1 (Zuniga et al., 1981). Kodwa-ke, ku-Pseudomonas stutzeri AN10, zonke izakhi zofuzo zokonakala kwe-naphthalene (i-nah kanye ne-sal operon) zitholakala ku-chromosome futhi kungenzeka ukuthi zitholakala ngemicimbi yokuguqulwa, ukuhlanganiswa kabusha, kanye nokuhlelwa kabusha (Bosch et al., 2000). Ku-Pseudomonas sp. CSV86, ama-nah kanye ne-sal operon atholakala ku-genome ngesimo se-ICE (ICECSV86). Isakhiwo sivikelwe yi-tRNAGly kulandelwe ukuphindaphinda okuqondile okubonisa izindawo zokuphinda kuhlanganiswe/zokunamathisela (attR kanye ne-attL) kanye ne-integrase efana ne-phage etholakala kuzo zombili izinhlangothi ze-tRNAGly, ngaleyo ndlela ifana nesakhi se-ICEclc (ICEclcB13 ku-Pseudomonas knackmusii yokudilizwa kwe-chlorocatechol). Kubikwe ukuthi izakhi zofuzo ku-ICE zingadluliselwa ngokuhlanganiswa ngemvamisa yokudlulisa ephansi kakhulu (10-8), ngaleyo ndlela zidlulisele izakhiwo zokudilizwa kumamukeli (Basu noPhale, 2008; Phale et al., 2019).
Iningi lamajini abangela ukuwohloka kwe-carbaryl litholakala kuma-plasmid. I-Arthrobacter sp. RC100 iqukethe ama-plasmid amathathu (i-pRC1, i-pRC2 kanye ne-pRC300) lapho ama-plasmid amabili ahlanganayo, i-pRC1 kanye ne-pRC2, efaka ama-enzyme aguqula i-carbaryl ibe yi-gentisate. Ngakolunye uhlangothi, ama-enzyme ahilelekile ekuguqulweni kwe-gentisate kuma-metabolites e-carbon aphakathi atholakala ku-chromosome (Hayaatsu et al., 1999). Amabhaktheriya ohlobo lwe-Rhizobium. I-Strain AC100, esetshenziselwa ukuguqulwa kwe-carbaryl ibe yi-1-naphthol, iqukethe i-plasmid pAC200, ephethe i-cehA gene efaka i-CH njengengxenye ye-Tnceh transposon ezungezwe yi-insertion element-like sequences (istA kanye ne-istB) (Hashimoto et al., 2002). Kuhlobo lwe-Sphingomonas CF06, i-carbaryl degradation gene kukholakala ukuthi ikhona kuma-plasmid amahlanu: i-pCF01, i-pCF02, i-pCF03, i-pCF04, kanye ne-pCF05. Ukuhlangana kwe-DNA kwala ma-plasmid kuphezulu, okubonisa ukuthi kukhona isenzakalo sokuphindaphindwa kwezakhi zofuzo (Feng et al., 1997). Ku-symbiont ebola i-carbaryl eyakhiwe izinhlobo ezimbili ze-Pseudomonas, uhlobo lwe-50581 luqukethe i-conjugative plasmid pCD1 (50 kb) ebhala i-mcd carbaryl hydrolase gene, kanti i-conjugative plasmid kuhlobo lwe-50552 ibhala i-enzyme ebola i-1-naphthol (Chapalamadugu noChaudhry, 1991). Kuhlobo lwe-Achromobacter WM111, i-mcd furadan hydrolase gene itholakala ku-plasmid engu-100 kb (pPDL11). Le gene iboniswe ukuthi ikhona kuma-plasmid ahlukene (100, 105, 115 noma 124 kb) kumabhaktheriya ahlukene avela ezifundeni ezahlukene zezwe (Parekh et al., 1995). Ku-Pseudomonas sp. C5pp, zonke izakhi zofuzo ezibangela ukuwohloka kwe-carbaryl zitholakala ku-genome ehlanganisa uchungechunge lwama-76.3 kb (Trivesi et al., 2016). Ukuhlaziywa kwezakhi zofuzo (6.15 Mb) kwembule ukuba khona kwama-MGE angu-42 nama-GEI angu-36, lapho ama-MGE angu-17 atholakala ku-supercontig A (76.3 kb) enokuqukethwe kwe-G+C okulinganiselwe okulinganiselwe (54–60 mol%), okuphakamisa izehlakalo zokudluliswa kwezakhi zofuzo ezivundlile (Trivesi et al., 2016). I-P. putida XWY-1 ibonisa uhlelo olufanayo lwezakhi zofuzo eziwohlokayo ze-carbaryl, kodwa lezi zakhi zofuzo zitholakala ku-plasmid (Zhu et al., 2019).
Ngaphezu kokusebenza kahle kwe-metabolic emazingeni e-biochemical kanye ne-genomic, ama-microorganisms aphinde abonise ezinye izakhiwo noma izimpendulo ezifana ne-chemotaxis, izakhiwo zokuguqulwa kobuso beseli, ukuhlukanisa, ukusetshenziswa okukhethekile, ukukhiqizwa kwe-biosurfactant, njll., okubasiza ukuthi basebenzise kahle kakhulu ukungcola okunuka kamnandi ezindaweni ezingcolisiwe (Isithombe 7).
Umfanekiso 7. Amasu ahlukene okuphendula kwamaseli ebhaktheriya elihlanza i-hydrocarbon elinuka kamnandi ukuze kutholakale ukubola okuphumelelayo kwamakhemikhali angcolisayo angaphandle.
Izimpendulo ze-chemotactic zibhekwa njengezici ezithuthukisa ukuwohloka kwezinto eziphilayo ezingcoliswe kakhulu ezindaweni zemvelo ezingcolile. (2002) zikhombisile ukuthi i-chemotaxis ye-Pseudomonas sp. G7 ku-naphthalene yandisa izinga lokuwohloka kwe-naphthalene ezinhlelweni zasemanzini. Uhlobo lwe-wild-type G7 lonakalise i-naphthalene ngokushesha kakhulu kunohlobo lwe-mutant olungenayo i-chemotaxis. Iphrotheni ye-NahY (ama-amino acid angu-538 ane-membrane topology) itholakale ihlanganiswa nezakhi zofuzo ze-metacleavage pathway ku-NAH7 plasmid, futhi njengama-transducer e-chemotaxis, le phrotheni ibonakala isebenza njenge-chemoreceptor yokuwohloka kwe-naphthalene (Grimm noHarwood 1997). Olunye ucwaningo lukaHansel et al. (2009) lukhombisile ukuthi iphrotheni iyi-chemotactic, kodwa izinga layo lokuwohloka liphezulu. (2011) ubonise impendulo ye-chemotactic ye-Pseudomonas (P. putida) ku-naphthalene yegesi, lapho ukusabalala kwesigaba segesi kuholele ekugelezeni okuqhubekayo kwe-naphthalene kumaseli, okulawula impendulo ye-chemotactic yamaseli. Abacwaningi basebenzise lokhu kuziphatha kwe-chemotactic ukuklama ama-microbes azothuthukisa izinga lokuwohloka. Izifundo zibonise ukuthi izindlela ze-chemosensory nazo zilawula eminye imisebenzi yamaseli njengokuhlukaniswa kwamaseli, ukulawulwa komjikelezo wamaseli, kanye nokwakheka kwe-biofilm, ngaleyo ndlela kusiza ukulawula izinga lokuwohloka. Kodwa-ke, ukusebenzisa le mpahla (i-chemotaxis) ukuze kuwohloke kahle kuphazanyiswa yizingqinamba eziningana. Izithiyo ezinkulu yilezi: (a) ama-receptor ahlukene e-paralogous aqaphela ama-compound/ligands afanayo; (b) ukuba khona kwama-receptor ahlukile, okungukuthi, i-tropism enamandla; (c) umehluko omkhulu wokulandelana ezindaweni zokuzwa zomndeni ofanayo wama-receptor; kanye (d) ukuntuleka kolwazi ngamaprotheni amakhulu ezinzwa zamagciwane (Ortega et al., 2017; Martin-Mora et al., 2018). Ngezinye izikhathi, ukubola kwe-biodegradation yama-aromatic hydrocarbon kukhiqiza ama-metabolites/intermediates amaningi, angaba yi-chemotactic eqenjini elilodwa lamabhaktheriya kodwa anyanyeke kwamanye, okwenza inqubo ibe nzima nakakhulu. Ukuze sithole ukusebenzisana kwama-ligands (ama-aromatic hydrocarbons) nama-chemical receptors, sakhe amaprotheni ezinzwa ezihlanganisiwe (i-PcaY, i-McfR, ne-NahY) ngokuhlanganisa izizinda zezinzwa kanye nezimpawu ze-Pseudomonas putida kanye ne-Escherichia coli, ezihlose ama-receptors ama-aromatic acid, ama-TCA intermediates, kanye ne-naphthalene, ngokulandelana (Luu et al., 2019).
Ngaphansi kwethonya le-naphthalene namanye ama-hydrocarbon aromatic polycyclic (ama-PAH), isakhiwo se-membrane yamagciwane kanye nobuqotho bama-microorganisms kushintsha kakhulu. Izifundo zibonise ukuthi i-naphthalene iphazamisa ukusebenzisana kwe-acyl chain ngokusebenzisana kwe-hydrophobic, ngaleyo ndlela yandisa ukuvuvukala nokugeleza kwe-membrane (Sikkema et al., 1995). Ukuze kulwiswane nalo mphumela omubi, amabhaktheriya alawula ukugeleza kwe-membrane ngokushintsha isilinganiso kanye nokwakheka kwe-fatty acid phakathi kwe-iso/anteiso branched-chain fatty acids kanye ne-isomerizing cis-unsaturated fatty acids kuma-trans-isomers ahambisanayo (Heipieper no-de Bont, 1994). Ku-Pseudomonas stutzeri ekhuliswe ekwelashweni kwe-naphthalene, isilinganiso se-fatty acid esigcwalisiwe kuya ku-unsaturated sanda kusuka ku-1.1 kuya ku-2.1, kanti ku-Pseudomonas JS150 lesi silinganiso sanda kusuka ku-7.5 kuya ku-12.0 (Mrozik et al., 2004). Lapho ikhuliswe ku-naphthalene, amaseli e-Achromobacter KA angu-3-5 abonise ukuhlangana kwamaseli azungeze amakristalu e-naphthalene kanye nokwehla kokushaja kobuso beseli (kusukela ku--22.5 kuya ku--2.5 mV) okuhambisana nokujiya kwe-cytoplasmic kanye ne-vacuolization, okubonisa izinguquko esakhiweni seseli kanye nezakhiwo zobuso beseli (Mohapatra et al., 2019). Nakuba izinguquko zeseli/zobuso zihlotshaniswa ngqo nokumuncwa okungcono kokungcola okunuka kamnandi, amasu afanele obunjiniyela be-bio awazange alungiselelwe ngokuphelele. Ukuphathwa kwesimo seseli akukaze kusetshenziswe kakhulu ukwenza ngcono izinqubo zebhayoloji (Volke noNikel, 2018). Ukususwa kwezakhi zofuzo ezithinta ukuhlukaniswa kweseli kubangela izinguquko ekubunjweni kweseli. Ukususwa kwezakhi zofuzo ezithinta ukuhlukaniswa kweseli kubangela izinguquko ekubunjweni kweseli. Ku-Bacillus subtilis, iphrotheni yeseli ye-septum i-SepF iboniswe ukuthi ihilelekile ekwakhekeni kwe-septum futhi iyadingeka ezinyathelweni ezilandelayo zokuhlukaniswa kweseli, kodwa akuyona i-gene ebalulekile. Ukususwa kwezakhi zofuzo ezifaka ama-peptide glycan hydrolases ku-Bacillus subtilis kuholele ekunwetshweni kwamaseli, ukwanda kwesilinganiso sokukhula esithile, kanye nokuthuthukiswa kwamandla okukhiqiza ama-enzyme (Cui et al., 2018).
Ukuhlanganiswa kwendlela yokuwohloka kwe-carbaryl kuye kwaphakanyiswa ukuze kufezwe ukuwohloka okuphumelelayo kwezinhlobo ze-Pseudomonas C5pp kanye ne-C7 (Kamini et al., 2018). Kuphakanyiswa ukuthi i-carbaryl ithuthwe iye esikhaleni se-periplasmic nge-external membrane septum kanye/noma ngama-diffusible porins. I-CH iyi-enzyme ye-periplasmic ekhuthaza i-hydrolysis ye-carbaryl ibe yi-1-naphthol, ezinzile kakhulu, ethanda amanzi futhi enobuthi kakhulu. I-CH itholakala ku-periplasm futhi inobungani obuphansi be-carbaryl, ngaleyo ndlela ilawula ukwakheka kwe-1-naphthol, ngaleyo ndlela ivimbele ukuqongelela kwayo emaselini futhi inciphise ubuthi bayo emaselini (Kamini et al., 2018). I-1-naphthol ephumelayo ithuthwa iye ku-cytoplasm ngaphesheya kwe-internal membrane ngokuhlukanisa kanye/noma ukusabalala, bese i-hydroxylated ibe yi-1,2-dihydroxynaphthalene yi-high-affinity enzyme 1NH ukuze kuqhutshekwe nokuguqulwa kwe-metabolism endleleni ephakathi kwekhabhoni.
Nakuba ama-microorganisms enamakhono ofuzo kanye nokusetshenziswa kwe-metabolic okonakalise imithombo yekhabhoni ye-xenobiotic, isakhiwo sokulandelana kokusetshenziswa kwawo (okungukuthi, ukusetshenziswa okukhethekile kwemithombo yekhabhoni elula kuneyinkimbinkimbi) kuyisithiyo esikhulu ekuboleni kwezinto eziphilayo. Ukuba khona nokusetshenziswa kwemithombo yekhabhoni elula kunciphisa izakhi zofuzo ezifaka ama-enzyme okonakalise imithombo yekhabhoni eyinkimbinkimbi/engakhethwa njenge-PAHs. Isibonelo esifundwe kahle ukuthi lapho i-glucose ne-lactose kuhlanganiswa ne-Escherichia coli, i-glucose isetshenziswa kahle kakhulu kune-lactose (Jacob and Monod, 1965). Kubikwe ukuthi ama-Pseudomonas anciphisa izinhlobo ezahlukene zama-PAH kanye nama-xenobiotic compounds njengemithombo yekhabhoni. Uhlu lokusetshenziswa komthombo yekhabhoni ku-Pseudomonas ama-organic acid > glucose > ama-aromatic compounds (Hylemon and Phibbs, 1972; Collier et al., 1996). Kodwa-ke, kukhona okuhlukile. Ngokuthakazelisayo, i-Pseudomonas sp. I-CSV86 ikhombisa isakhiwo esiyingqayizivele sokulandelana kwesimo esisebenzisa ngokukhethekile ama-hydrocarbon aromatic (i-benzoic acid, i-naphthalene, njll.) kune-glucose futhi ixube ama-hydrocarbon aromatic nama-organic acid (Basu et al., 2006). Kuleli gciwane, izakhi zofuzo zokuwohloka nokuthuthwa kwama-hydrocarbon aromatic azincishiswa ngisho nalapho kukhona umthombo wesibili wekhabhoni njenge-glucose noma ama-organic acid. Lapho ikhuliswe ku-glucose kanye ne-aromatic hydrocarbons medium, kwaphawulwa ukuthi izakhi zofuzo zokuthuthwa kwe-glucose kanye ne-metabolism zazincishisiwe, ama-hydrocarbon aromatic asetshenziswa esigabeni sokuqala se-log, kanti i-glucose yasetshenziswa esigabeni sesibili se-log (Basu et al., 2006; Choudhary et al., 2017). Ngakolunye uhlangothi, ukuba khona kwama-organic acid akuzange kuthinte ukubonakaliswa kwe-aromatic hydrocarbon metabolism, ngakho-ke leli gciwane kulindeleke ukuthi libe uhlobo olufanele lwezifundo zokubola kwe-bio (Phale et al., 2020).
Kuyaziwa kahle ukuthi ukuguqulwa kwe-hydrocarbon kungabangela ukucindezeleka kwe-oxidative kanye nokwanda kwama-enzyme e-antioxidant kuma-microorganisms. Ukubola kwe-naphthalene okungasebenzi kahle kokubili kumaseli esigaba esimile kanye nokuba khona kwamakhemikhali anobuthi kuholela ekwakhekeni kwezinhlobo ze-oxygen ezisebenzayo (ROS) (Kang et al. 2006). Njengoba ama-enzyme abulala i-naphthalene aqukethe amaqoqo e-iron-sulfur, ngaphansi kokucindezeleka kwe-oxidative, i-iron kumaprotheni e-heme kanye ne-iron-sulfur azokhiqizwa, okuholela ekungasebenzini kwamaprotheni. I-Ferredoxin-NADP+ reductase (Fpr), kanye ne-superoxide dismutase (SOD), ilawula ukusabela kwe-revoluble redox phakathi kwe-NADP+/NADPH nama-molecule amabili e-ferredoxin noma i-flavodoxin, ngaleyo ndlela isusa i-ROS futhi ibuyisele isikhungo se-iron-sulfur ngaphansi kokucindezeleka kwe-oxidative (Li et al. 2006). Kubikwe ukuthi kokubili i-Fpr kanye ne-SodA (i-SOD) kuma-Pseudomonas kungabangelwa ukucindezeleka kwe-oxidative, futhi ukwanda kwemisebenzi ye-SOD kanye ne-catalase kwabonwa ezinhlotsheni ezine ze-Pseudomonas (O1, W1, As1, kanye ne-G1) ngesikhathi sokukhula ngaphansi kwezimo ezengeziwe ze-naphthalene (Kang et al., 2006). Izifundo zibonise ukuthi ukwengezwa kwama-antioxidants njenge-ascorbic acid noma i-ferrous iron (Fe2+) kungandisa izinga lokukhula kwe-naphthalene. Lapho i-Rhodococcus erythropolis ikhula endaweni ye-naphthalene, ukuqoshwa kwezakhi zofuzo ze-cytochrome P450 ezihlobene nokucindezeleka kwe-oxidative kufaka phakathi i-sodA (Fe/Mn superoxide dismutase), i-sodC (Cu/Zn superoxide dismutase), kanye ne-recA kwanda (Sazykin et al., 2019). Ukuhlaziywa kwe-proteomic okuqhathanisayo kwamaseli e-Pseudomonas akhuliswe ku-naphthalene kubonise ukuthi ukwandiswa kwamaprotheni ahlukahlukene ahlobene nempendulo yokucindezeleka kwe-oxidative kuyindlela yokubhekana nokucindezeleka (Herbst et al., 2013).
Kubikwe ukuthi ama-microorganisms akhiqiza ama-biosurfactants ngaphansi kwesenzo semithombo yekhabhoni e-hydrophobic. Lawa ma-surfactants angama-compound asebenzayo ebusweni ahlala emanzini angakha ama-aggregates emanzini kawoyela noma emanzini omoya. Lokhu kukhuthaza ukuncibilika okungamanga futhi kusiza ukumuncwa kwama-hydrocarbon aromatic, okuholela ekubolekeni kwe-biogradation okuphumelelayo (Rahman et al., 2002). Ngenxa yalezi zakhiwo, ama-biosurfactants asetshenziswa kabanzi ezimbonini ezahlukahlukene. Ukwengezwa kwama-surfactants amakhemikhali noma ama-biosurfactants emasikweni amabhaktheriya kungathuthukisa ukusebenza kahle kanye nezinga lokuwohloka kwe-hydrocarbon. Phakathi kwama-biosurfactants, ama-rhamnolipids akhiqizwa yi-Pseudomonas aeruginosa afundwe kabanzi futhi achazwa (Hisatsuka et al., 1971; Rahman et al., 2002). Ngaphezu kwalokho, ezinye izinhlobo ze-biosurfactants zifaka phakathi ama-lipopeptides (ama-mucins avela ku-Pseudomonas fluorescens), i-emulsifier 378 (evela ku-Pseudomonas fluorescens) (Rosenberg noRon, 1999), ama-lipid e-trehalose disaccharide avela ku-Rhodococcus (Ramdahl, 1985), i-lichenin evela ku-Bacillus (Saraswathy no-Hallberg, 2002), kanye ne-surfactant evela ku-Bacillus subtilis (Siegmund no-Wagner, 1991) kanye ne-Bacillus amyloliquefaciens (Zhi et al., 2017). Lawa ma-surfactants anamandla aboniswe ukuthi anciphisa ukungezwani kobuso kusuka ku-72 dynes/cm kuya ngaphansi kuka-30 dynes/cm, okuvumela ukumuncwa okungcono kwe-hydrocarbon. Kubikwe ukuthi i-Pseudomonas, i-Bacillus, i-Rhodococcus, i-Burkholderia nezinye izinhlobo zamagciwane zingakhiqiza ama-biosurfactants ahlukahlukene e-rhamnolipid kanye ne-glycolipid uma zikhuliswe ku-naphthalene kanye ne-methylnaphthalene media (Kanga et al., 1997; Puntus et al., 2005). I-Pseudomonas maltophilia CSV89 ingakhiqiza i-extracellular biosurfactant Biosur-Pm uma ikhuliswe kumakhemikhali aromatic njenge-naphthoic acid (Phale et al., 1995). I-kinetics yokwakheka kwe-Biosur-Pm ibonise ukuthi ukwakheka kwayo kuyinqubo encike ekukhuleni nasekukhuleni kwe-pH. Kutholakale ukuthi inani le-Biosur-Pm elikhiqizwa amaseli ku-pH engathathi hlangothi laliphezulu kunalelo eliku-pH 8.5. Amaseli akhuliswe ku-pH 8.5 ayengathandi amanzi futhi ayenobuhlobo obuphezulu bamakhemikhali aromatic kanye ne-aliphatic kunamaseli akhuliswe ku-pH 7.0. Ku-Rhodococcus spp. I-N6, isilinganiso esiphezulu sekhabhoni kuya ku-nitrogen (C:N) kanye nomkhawulo wensimbi yizimo ezifanele kakhulu zokukhiqizwa kwama-biosurfactants angaphandle (Mutalik et al., 2008). Kuye kwenziwa imizamo yokuthuthukisa i-biosynthesis yama-biosurfactants (ama-surfactin) ngokwenza ngcono izinhlobo kanye nokubiliswa. Kodwa-ke, izinga le-surfactant endaweni yokukhulisa liphansi (1.0 g/L), okuletha inselele ekukhiqizweni okukhulu (Jiao et al., 2017; Wu et al., 2019). Ngakho-ke, izindlela zobunjiniyela bezakhi zofuzo zisetshenziswe ukuthuthukisa i-biosynthesis yayo. Kodwa-ke, ukuguqulwa kwayo kobunjiniyela kunzima ngenxa yobukhulu obukhulu be-operon (∼25 kb) kanye nokulawulwa okuyinkimbinkimbi kwe-biosynthetic kohlelo lokuzwa lwe-quorum (Jiao et al., 2017; Wu et al., 2019). Kuye kwenziwa izinguquko eziningana zobunjiniyela bezakhi zofuzo kumabhaktheriya e-Bacillus, okuhloswe kakhulu ukwandisa ukukhiqizwa kwe-surfactin ngokufaka esikhundleni se-promoter (srfA operon), ukuveza ngokweqile iphrotheni yokuthumela i-surfactin i-YerP kanye nezici zokulawula i-ComX ne-PhrC (Jiao et al., 2017). Kodwa-ke, lezi zindlela zobunjiniyela bezakhi zofuzo zifinyelele ukuguqulwa kwezakhi zofuzo okukodwa noma okumbalwa futhi azikafiki ekukhiqizweni kwezentengiselwano. Ngakho-ke, kudingeka ucwaningo olwengeziwe lwezindlela zokwenza ngcono ezisekelwe olwazini.
Izifundo zokubola kwe-PAH zenziwa kakhulu ngaphansi kwezimo ezijwayelekile zelebhu. Kodwa-ke, ezindaweni ezingcolisiwe noma ezindaweni ezingcolisiwe, izici eziningi ze-abiotic kanye ne-biotic (izinga lokushisa, i-pH, umoya-mpilo, ukutholakala kwezakhamzimba, ukutholakala kwe-substrate, amanye ama-xenobiotic, ukuvinjelwa komkhiqizo wokugcina, njll.) kuye kwabonakala kushintsha futhi kuthonya amandla okubola kwama-microorganisms.
Izinga lokushisa linomthelela omkhulu ekubolekeni kwe-PAH. Njengoba izinga lokushisa likhuphuka, ukuhlushwa kwe-oxygen encibilikisiwe kuyehla, okuthinta i-metabolism yama-microorganisms e-aerobic, njengoba edinga i-molecule oxygen njengenye yezingxenye ze-oxygenase ezenza ukusabela kwe-hydroxylation noma i-ring cleavage. Kuvame ukuphawulwa ukuthi izinga lokushisa eliphakeme liguqula ama-PAH angumzali abe ama-compounds anobuthi kakhulu, ngaleyo ndlela kuvimbele ukubola kwe-bio (Muller et al., 1998).
Kuye kwaphawulwa ukuthi izindawo eziningi ezingcoliswe yi-PAH zinamanani aphezulu e-pH, njengezindawo ezingcoliswe yi-acid mine drainage (pH 1–4) kanye nezindawo zegesi yemvelo/amalahle ezingcoliswe yi-alkaline leachate (pH 8–12). Lezi zimo zingathinta kakhulu inqubo yokubola kwezinto eziphilayo. Ngakho-ke, ngaphambi kokusebenzisa ama-microorganisms ukuze kulungiswe izinto eziphilayo, kunconywa ukulungisa i-pH ngokungeza amakhemikhali afanele (anamandla okunciphisa i-oxidation aphakathi kuya kwaphansi kakhulu) njenge-ammonium sulfate noma i-ammonium nitrate yenhlabathi ye-alkaline noma i-lime ene-calcium carbonate noma i-magnesium carbonate yezindawo ezine-acidic (Bowlen et al. 1995; Gupta no-Sar 2020).
Ukunikezwa komoya-mpilo endaweni ethintekile kuyisici esivimbela izinga lokubola kwe-PAH. Ngenxa yezimo ze-redox zemvelo, izinqubo zokulungisa umoya-mpilo endaweni ngokuvamile zidinga ukungeniswa komoya-mpilo emithonjeni yangaphandle (ukulima, ukusabalalisa umoya, kanye nokwengezwa kwamakhemikhali) (Pardieck et al., 1992). U-Odenkranz et al. (1996) babonise ukuthi ukungezwa kwe-magnesium peroxide (i-compound ekhulula umoya-mpilo) endaweni engcolile kungalungisa kahle amakhemikhali e-BTEX. Olunye ucwaningo luhlole ukuwohloka kwe-phenol kanye ne-BTEX endaweni engcolile ngokufaka i-sodium nitrate kanye nokwakha imithombo yokukhipha ukuze kufezwe ukulungiswa komoya-mpilo okuphumelelayo (Bewley noWebb, 2001).