title: Biodegradation of phthalic acid esters by a newly isolated Mycobacterium sp. YC-RL4 and the bioprocess with environmental samples.
abstract: Bacterial strain YC-RL4, capable of utilizing phthalic acid esters (PAEs) as the sole carbon source for growth, was isolated from petroleum-contaminated soil. Strain YC-RL4 was identified as Mycobacterium sp. by 16S rRNA gene analysis and Biolog tests. Mycobacterium sp. YC-RL4 could rapidly degrade dibutyl phthalate (DBP), diethyl phthalate (DEP), dimethyl phthalate (DMP), dicyclohexyl phthalate (DCHP), and di-(2-ethylhexyl) phthalate (DEHP) under both individual and mixed conditions, and all the degradation rates were above 85.0 % within 5 days. The effects of environmental factors which might affect the degrading process were optimized as 30 °C and pH 8.0. The DEHP metabolites were detected by HPLC-MS and the degradation pathway was deduced tentatively. DEHP was transformed into phthalic acid (PA) via mono (2-ethylhexyl) phthalate (MEHP) and PA was further utilized for growth via benzoic acid (BA) degradation pathway. Cell surface hydrophobicity (CSH) assays illuminated that the strain YC-RL4 was of higher hydrophobicity while grown on DEHP and CSH increased with the higher DEHP concentration. The degradation rates of DEHP by strain YC-RL4 in different environmental samples was around 62.0 to 83.3 % and strain YC-RL4 survived well in the soil sample. These results suggested that the strain YC-RL4 could be used as a potential and efficient PAE degrader for the bioremediation of contaminated sites.
authors.affiliation: Graduate School of Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Ren
authors.affiliation: Graduate School of Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Graduate School of Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Nahurira
authors.initials: N
authors.lastname: Ruth
authors.affiliation: Graduate School of Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Qiao
authors.affiliation: Graduate School of Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Junhuan
authors.initials: J
authors.lastname: Wang
authors.affiliation: Graduate School of Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Baisuo
authors.initials: B
authors.lastname: Zhao
authors.affiliation: Graduate School of Chinese Academy of Agricultural Sciences, Beijing, 100081, China. yanyanchun@caas.cn.
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Yan
mesh_terms: D001673:Biodegradation, Environmental; D003993:Dibutyl Phthalate / Q000378:metabolism; D004952:Esters / Q000378:metabolism; D009161:Mycobacterium / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010795:Phthalic Acids / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D004952:Esters; D010795:Phthalic Acids; D012336:RNA, Ribosomal, 16S; C024629:dimethyl phthalate; D003993:Dibutyl Phthalate; C032279:phthalic acid; C036042:dicyclohexyl phthalate; C007379:diethyl phthalate
keywords: Bioremediation; Cell surface hydrophobicity; Metabolic mechanism; Mycobacterium sp.; Phthalic acid esters