Biodegradation of phenanthrene at high concentrations by <i>Acidovorax</i><scp>sp. JG5</scp> and its functional genomic analysis
Xiaoyong Liao, Junpeng Luo, Daniel P. Cassidy, Li You, Huan Tao, Yishu Zhao
Abstract
Abstract BACKGROUND Phenanthrene (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. RESULTS A 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. CONCLUSION Acidovorax 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