TY - JOUR
T1 - Enantioselective degradation and unidirectional chiral inversion of 2-phenylbutyric acid, an intermediate from linear alkylbenzene, by Xanthobacter flavus PA1
AU - Liu, Yishan
AU - Han, Ping
AU - Li, Xiao yan
AU - Shih, Kaimin
AU - Gu, Ji Dong
N1 - Funding Information:
This research project was supported in part by grants from Faculty of Science , Faculty of Engineering and The University of Hong Kong on Sustainable Water . We would like to thank Xiang Li and Baofu Zheng for their help with NMR spectrometry and stimulating discussions on enantiomer-specific analyses, Li Pan for 16S rRNA gene sequencing, and Jessie Lai for laboratory assistance.
PY - 2011/9/15
Y1 - 2011/9/15
N2 - Microbial degradation of the chiral 2-phenylbutyric acid (2-PBA), a metabolite of surfactant linear alkylbenzene sulfonates (LAS), was investigated using both racemic and enantiomer-pure compounds together with quantitative stereoselective analyses. A pure culture of bacteria, identified as Xanthobacter flavus strain PA1 isolated from the mangrove sediment of Hong Kong Mai Po Nature Reserve, was able to utilize the racemic 2-PBA as well as the single enantiomers as the sole source of carbon and energy. In the presence of the racemic compounds, X. flavus PA1 degraded both (R) and (S) forms of enantiomers to completion in a sequential manner in which the (S) enantiomer disappeared much faster than the (R) enantiomer. When the single pure enantiomer was supplied as the sole substrate, a unidirectional chiral inversion involving (S) enantiomer to (R) enantiomer was evident. No major difference was observed in the degradation intermediates with either of the individual enantiomers when used as the growth substrate. Two major degradation intermediates were detected and identified as 3-hydroxy-2-phenylbutanoic acid and 4-methyl-3-phenyloxetan-2-one, using a combination of liquid chromatography-mass spectrometry (LC-MS), and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The biochemical degradation pathway follows an initial oxidation of the alkyl side chain before aromatic ring cleavage. This study reveals new evidence for enantiomeric inversion catalyzed by pure culture of environmental bacteria and emphasizes the significant differences between the two enantiomers in their environmental fates.
AB - Microbial degradation of the chiral 2-phenylbutyric acid (2-PBA), a metabolite of surfactant linear alkylbenzene sulfonates (LAS), was investigated using both racemic and enantiomer-pure compounds together with quantitative stereoselective analyses. A pure culture of bacteria, identified as Xanthobacter flavus strain PA1 isolated from the mangrove sediment of Hong Kong Mai Po Nature Reserve, was able to utilize the racemic 2-PBA as well as the single enantiomers as the sole source of carbon and energy. In the presence of the racemic compounds, X. flavus PA1 degraded both (R) and (S) forms of enantiomers to completion in a sequential manner in which the (S) enantiomer disappeared much faster than the (R) enantiomer. When the single pure enantiomer was supplied as the sole substrate, a unidirectional chiral inversion involving (S) enantiomer to (R) enantiomer was evident. No major difference was observed in the degradation intermediates with either of the individual enantiomers when used as the growth substrate. Two major degradation intermediates were detected and identified as 3-hydroxy-2-phenylbutanoic acid and 4-methyl-3-phenyloxetan-2-one, using a combination of liquid chromatography-mass spectrometry (LC-MS), and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The biochemical degradation pathway follows an initial oxidation of the alkyl side chain before aromatic ring cleavage. This study reveals new evidence for enantiomeric inversion catalyzed by pure culture of environmental bacteria and emphasizes the significant differences between the two enantiomers in their environmental fates.
KW - 2-Phenylbutyric acid
KW - Chiral inversion
KW - Enantioselective biodegradation
KW - Linear alkylbenzene sulfonates
KW - Xanthobacter flavus
UR - http://www.scopus.com/inward/record.url?scp=80052032514&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2011.06.088
DO - 10.1016/j.jhazmat.2011.06.088
M3 - 文章
C2 - 21794984
AN - SCOPUS:80052032514
SN - 0304-3894
VL - 192
SP - 1633
EP - 1640
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
IS - 3
ER -