New insights of crude oil biodegradation construction by microbial consortium B10: Responded substrates, genomics, biodegradation mechanism and pathways

Crude oil pollution caused by production and living demands has existed for decades, which adverse to ecological security and human health. Microbial degradation of crude oil is a green and effective remediation method. This study is intended to develop a microbial consortium based on the commonness and differences of key genes and response substrates of the strains to efficiently degrade crude oil. Four crude oil-contaminated soil dwelling bacteria, CO1, CO2, CO6 and CO7, were isolated whose crude oil degradation and emulsification performance were evaluated. Subsequently, revealing their genomic characteristics and response substrates, the key genes of CO1 were mapped to genes alkB, hcaD; CO2 were located at genes andAd, andAc; CO6 were mapped to genes ladA, alkM, pcaH, benB-xylY and CO7 were located at gene cypd-E. Consortium of Ochrobactrum.sp, Pseudomonas aeruginosa and Bacillus.sp were selected as microbial consortium B10. Compared with single strain, the crude oil removal efficiency of B10 via RSM method optimizing is up to 51.58 % in 6 days, where the C11-C18 removal rate is up to 78.51 %. Besides, the biodegradation rates of C26-C29 and C33-35 increased by 36.20 % and 30.51 %, respectively. The possible metabolic pathways of crude oil were proposed, including aldehyde bond (H-C=O) and ketone bond (C-O-C) hydrodehydration, ring opening of cyclic ether, C-C bond oxidation of benzene ring and ring-opening hydrolysis of gentisic acid reactions. Altogether, this study provides a new insight into high-performance microbial consortia construction in crude oil biodegradation.