302 / 2022-03-03 22:51:43

Biodegradation characterization and genomic function analysis of bis (2-ethylhexyl) phthalate esters-degrading bacteria Methylobacterium sp. F05R

contaminated site, land reclamation, microbial degradation, DEHP

Environmental Science and Engineering > 3. Land Reclamation and Ecology Rehabilitation

A Gram-negative aerobic strain Methylobacterium sp. F05R isolated from the topsoil of a landfill can utilize a variety of phthalates and efficiently degrade bis (2-ethylhexyl) phthalate esters (DEHP). Under optimal conditions, 200 mg/L DEHP could be degraded by 92.2% in 7 days. Based on Gas Chromatography-Mass Spectrometry (GC-MS) analysis, monoethylhexyl phthalate (MEHP) and phthalic acid (PA) were considered to be the major metabolites. Combined with the genomic annotation of strain F05R, it is speculated that DEHP will generate 3-acetyl-CoA through degreasing, dehydrogenation, oxidation and other pathways, and then enter the TCA cycle to complete degradation. The substrate broad spectrum test proved that strain F05R was able to grow with 200 mg/L of DBP, BBP, and DnOP as the sole carbon source, and the degradation effect of these three PAEs were 85%, 84%, and 74% in 6 days, respectively. And the degradation ability of DBP with short branch chain is stronger than DnOP with long branch chain. In addition, strain F05R could effectively remove DEHP in contaminated soil. When the water-soil ratio is 2: 1 and the culture speed is 180 r / min, DEHP (50 mg/kg soil) in the contaminated soil can be degraded by 76.7% within 7 days. These results indicate that F05R strain has great potential for bioremediation of PAEs contamination.