Construction Of An Artificial Microbial Consortium For Pahs Phenanthrene Biodegradation And Analysis Of Its Metabolic Communication

Polycyclic aromatic hydrocarbons(PAHs)are harmful to human health and difficult to eliminate from the environment.Among PAHs,phenanthrene is the smallest representative.In this study,a phenanthrene degrading strain,Pseudomonas aeruginosa PH1,was isolated from oil-contaminated soil.An artificial microbial consortium comprising two engineered microorganisms,Escherichia coli HY1 and P.aeruginosa PH2,was assembled for further phenanthrene biodegradation.E.coli HY1 harbored two modules of terminal dioxygenase and an electron transfer chain,while P.aeruginosa PH2 contained a module of catechol 1,2-dioxygenase.The degradation of phenanthrene by the wild degrader,P.aeruginosa PH1,was 44.7%,43.35% and 81.43%,in mineral salt medium with 100 mg/L phenanthrene,100 mg/L phenanthrene and 2% oil,and 100 mg/L phenanthrene and 2% n-hexadecane,respectively.In contrast,the artificial consortium degraded 71.05%,79.9% and 87.92% of the same level of phenanthrene in the corresponding media,achieving a much higher efficiency.Moreover,gas chromatography-mass spectrometry confirmed that the artificial microbial consortium first oxidized phenanthrene to 9,10-dihydroxy phenanthrene and 1,2-dihydroxy phenanthrene and then metabolized these intermediates via catechol to carbon dioxide and water.In this process,E.coli HY1 dominated in the initial oxidation,and P.aeruginosa PH2 was primarily responsible for cleaving the rings.These findings indicate that the artificially constructed microbial consortium provides a potential method for better PAHs degradation.