Whole genome analysis of Comamonas sp. USTBZA1 for biodegrading diethyl phthalate

Abstract

Extensive use of phthalic acid esters (PAEs) as plasticizer causes diffusion into the environment, which posed a great threat to mankind. In the present study, one promising bacterial strain for biodegrading diethyl phthalate (DEP) was successfully isolated from activated sludge and characterized as Comamonas sp. USTBZA1 based on 16S rRNA sequence analysis. Under the optimal conditions of pH 7.5, 30℃ and inoculum volume ratio of 6%, initial DEP of 50 mg/L could be completely biodegrade by strain USTBZA1 within 24 h which conformed to the Gompertz model. Based on Q-TOF LC/MS analysis, monoethyl phthalate (MEP) and phthalic acid (PA) were identified as the metabolic products of DEP biodegradation by USTBZA1. Furthermore, the whole genome of Comamonas sp. USTBZA1 was analyzed to excavate PAEs catabolic genes in stain USTBZA1. There were 3 and 41 genes encoding esterase/arylesterase and hydrolase respectively which could involve in PAEs hydrolysis, and two genes regions (pht34512 and pht4253) were responsible for the conversion of PA to protocatechuate (PCA), and two genes regions (ligCBAIKJ) are involved in PCA metabolism in USTBZA1. These results substantiated that Comamonas sp. USTBZA1 had potential application in the DEP bioremediation.