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Journal of Ecosystem & Ecography | ISSN: 2157-7625 | Volume 8
July 11-12, 2018 | Toronto, Canada
International Conference on
Environmental Microbiology & Microbial Ecology
International Conference on
Ecology, Ecosystems & Conservation Biology
&
Degradation mechanism for phthalic acid esters (PAEs) degrading bacterium
Yanchun Yan, Baisuo Zhao, Ting Yang, Yang Jia, Shuanghu Fan, Junhuan Wang
and
Jiayi Wang
Ruth Nahurira Graduate School of Chinese Academy of Agricultural Sciences, China
D
i-(2-ethylehxyl) phthalate (DEHP) is the most broadly representative phthalate esters (PAEs) used as a plasticizer and
considered an endocrine-disrupting chemical. An efficient DEHP-degrading strain
Rhodococcus ruber
YC-YT1, with salt
tolerance (0~12% NaCl), is the first DEHP-degrader isolated from marine plastic debris around coastal saline seawater, which
could completely degraded 100 mg/L DEHP within 72 hours. Single factors (pH, temperature, and glucose) analysis and the
optimum degradation conditions for the strain were measured by response surface methodology (RSM). According to HPLC-
MS analysis, DEHP was transformed by strain YC-YT1 into phthalate (PA) via mono (2-ethylehxyl) phthalate (MEHP), and
then PA was used for cell growth. Furthermore, YC-YT1 metabolized initial concentrations of DEHP from 0.5 to 1000 mg/L.
Especially, YC-YT1 degraded up to 60% of 0.5 mg/L DEHP. Moreover, compared with previous reports, strain YC-YT1 has
the largest substrate spectrum, degrading up to 13 kinds of PAEs as well as diphenyl, PA, benzoic acid, protocatechuic acid
(PCA), and 1,2,3,3-tetrachlorobenzene. Strain YC-YT1 could adjust its cell surface hydrophobicity (CSH) in the environment
and 79.7~95.9% of DEHP-contaminated soil and water was remedied. These results demonstrate that strain YC-YT1 has vast
potential to bioremediate various DEHP-contaminated environments, especially in saline environments. The whole genome
sequence of strain YC-YT1 was obtained by the PacBio sequencing platform and submitted to GenBank (CP023712), which
contained a circular genome and two plasmids. The genes and gene clusters involved in the degradation of PAEs and aromatic
compounds, especially the phthalate dioxygenase genes and ring- cleavage dioxygenase genes, which involved the degradation
of diphenyl, PCA, benzoate and phthalate were analyzed by comparative genomics analysis. Two genes (
Dehp1199 and
Mehp4077
) encoding DEHP degrading esterases were obtained, condon optimization, expressed and verified. Dehp1199 is a
novel alkaline esterase and the enzymological characteristics were analyzed.
Biography
Yanchun Yan has her expertise in bioremediation of environmental pollution and passion in improving the health and wellbeing. Her research team has been focused
on the bioremediation for more than twenty years, and they have isolated more than 60 strains of bacteria or fungi capable of degrading pesticides or environmental
estrogen chemicals. The degradation characteristics of the strains and a number of genes or gene clusters encoding key enzymes were investigated. These
researches provided significant resources of strains and genes for bioremediation, and lay theoretical foundation for the degradation mechanism of pollutants.
yanyanchun@caas.cnYanchun Yan et al., J Ecosys Ecograph 2018, Volume 8
DOI: 10.4172/2157-7625-C3-039