Biodegradation of phenanthrene at high concentrations by Acidovoraxsp. JG5 and its functional genomic analysis

Abstract

AbstractBACKGROUNDPhenanthrene (PHE) is a widespread, highly‐toxic, and biodegradable polycyclic aromatic hydrocarbon (PAH) that can be found with high concentrations in multiple industrial sites. For the efficient biodegradation of PHE, especially for the high concentrations, a PHE‐degrading Acidovorax strain was isolated from a soil contaminated for decades with PAH; its ability to degrade PHE was investigated and the pathways involved were identified.RESULTSA PHE‐degrading strain was isolated and identified as Acidovorax sp. JG5. The bacterium completely degraded 200 mg·L−1 PHE in 24 h and it degraded over 90% of PHE in solutions ranging from 500 to 1500 mg·L−1 in 48 h. Key metabolites, such as 9,10‐phenanthraquinone, 2‐hydroxy‐1‐naphthoic acid, protocatechuic acid, phthalic acid, pyruvic acid, and salicylic acid, were detected during PHE biodegradation. Twelve genes related to PHE biodegradation (e.g., nahAa, pht5, ligA, and dmp cluster) were also revealed. Two PHE degradation pathways are proposed based on these metabolites and genes.CONCLUSIONAcidovorax sp. JG5 exhibits a high tolerance to PHE and high rates of degradation, along with a tremendous potential for the bioremediation of heavy PAH contamination. © 2021 Society of Chemical Industry