Research
| Title： | Biodegradation of phthalate acid esters by a versatile PAE-degrading strain Rhodococcus sp. LW-XY12 and associated genomic analysis |
|---|---|
| First author： | Song, Xiaoyong; Zhang, Zihan; Dai, Yanran; Cun, Deshou; Cui, Baihui; Wang, Yuewei; Fan, Yaocheng; Tang, Haibin; Qiu, Liang; Wang, Feihua; Qiu, Dongru; Liang, Wei |
| Journal： | INTERNATIONAL BIODETERIORATION & BIODEGRADATION |
| Years： | 2022 |
| DOI： | 10.1016/j.ibiod.2022.105399 |
| Abstract： | Di-(2-ethylhexyl) phthalate (DEHP), the most extensively used phthalate acid esters (PAEs), poses a potential risk to human and environment. A novel bacterial strain, Rhodococcus sp. LW-XY12, with efficient PAE-degrading capability, was isolated from activated sludge. Strain LW-XY12 could degrade 96.91 +/-& nbsp;0.68% of DEHP (500 mg L-1) within 32 h. The degradation curves of DEHP (50-1500 mg L-1) and PAE mixture (500 mg L-1 each) fitted well with the modified Gomperz kinetics model. DEHP metabolic pathway was reconstructed by using genome annotation and metabolic intermediate analyses. The DEHP metabolic pathway might comprise deesterification and beta-oxidation. Homologous modeling and molecular docking analysis revealed that DEHP and MEHP (mono-(2-ethylhexyl) phthalate) could be bound to putative carboxylesterase (KXC42_04905) via hydrogen bonding and hydrophobic interaction. A conserved catalytic triad (Ser195-Glu319-His412) might act as an active protein pocket and catalyze the hydrolysis of DEHP. Carboxylesterase (KXC42_04905) could hydrolyze ester bond and a possible mechanism underlying ester bond hydrolysis catalyzed by the carboxylesterase was proposed. Protocatechuate 3,4-dioxygenase, 3-oxoadipate CoA-transferase, benzoate 1,2-dioxygenase, catechol 1,2-dioxygenase, and catechol 2,3-dioxygenase transcripts were detected and significantly up regulated under DEHP induction. This study sheds light on the functional genes associated with DEHP degradation and metabolic mechanism in this versatile bacterium for degradation of PAEs. |
