PROCESS BIOCHEMISTRY
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2019
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IF 2.883
Xinyun Xu,Jiahao Wang,Ting Yu,Haohan Nian,Hui Zhang,Guangli Wang,Feng Li
Aryloxyphenoxypropionate (AOPP) herbicides with a chiral center are widely used to selectively remove annual and perennial grasses. However, the study of the enzymes involved in enantioselective degradation of AOPP herbicides is limited. A novel family VIII carboxylesterase gene, estwx , hydrolyzed the ester bond cleavage of AOPP herbicides to form the corresponding acid and alkyl side chain alcohol, was cloned from Brevundimonas sp. strain QPT-2 and overexpressed in E. coli BL21. The purified recombinant EstWX was shown to hydrolyze a wide range of AOPP herbicides with various catalytic efficiencies. The enantioselectivity assay indicated that EstWX preferentially catalyzed the hydrolysis of the R -enantiomer of AOPP herbicides. The S73, K76, Y196 together with W368 residues, especially S73 and Y196, were essential for the catalytic function of the carboxylesterase. EstWX is a promising candidate for the bioremediation of multiple AOPP herbicide-contaminated environments and for future mechanism studies on the enantioselective degradation of chiral AOPP herbicides.
研究领域:
环境科学
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微生物学
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酶学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2016
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IF 4.836
Hui Zhang,Mengya Li,Jie Li,Guangli Wang,Feng Li,Dayong Xu,Yuan Liu,Minghua Xiong
A natural consortium, named L1, of Rhodococcus sp. JT-3 and Brevundimonas sp. JT-9 was obtained from quizalofop- p -ethyl (QE) polluted soil. The consortium was able to use QE as a sole carbon source for growth and degraded 100 mg L −1 of QE in 60 h. Strain JT-3 initiated the catabolism of QE to quizalofop acid (QA), which was used by strain JT-9 as carbon source for growth and to simultaneously feed strain JT-3. A novel esterase EstS-JT, which was responsible for the transformation of QE to QA and essential for the mineralization of QE by the consortium, was cloned from strain JT-3. EstS-JT showed low amino acid identity to other reported esterases from esterase family VIII and represents a new member of this family. The deduced amino acid sequence contained the esterase family VIII conserved motifs S-X-X-K, YSV and WAG. The purified recombinant EstS-JT displayed maximal esterase activity at 35 °C and pH 7.5. An inhibitor assay, site-directed mutagenesis and 3D modeling analysis revealed that S 64 , K 67 and Y 175 were essential for catalysis and probably comprised the catalytic center of EstS-JT. Additionally, EstS-JT had broad substrate specificity and was capable of hydrolyzing p -nitrophenyl esters (C 2 -C 8 ) and various AOPP herbicides.
研究领域:
环境科学
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微生物学
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生物化学
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产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
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2021
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IF 7.086
Ting He,Jianguo Bao,Yifei Leng,Shuqiong Kong,Jiangkun Du,Xu Li
Doxycycline (DC) is a second generation tetracycline antibiotic and its occurrence in the aquatic environment due to the discharge of municipal and agricultural wastes has called for technologies to effectively remove DC from water. The objective of the study was to characterize the synergistic benefits of adsorption and biotransformation in removing DC from water using rice straw particles (RSPs) covered with DC degrading bacteria, Brevundimonas naejangsanensis strain DD1. First, optimal experimental conditions were identified for individual processes, i.e., hydrolysis, adsorption, and biotransformation, in terms of their performance of removing DC from water. Then, synergistic effects between adsorption and biotransformation were demonstrated by adding DD1-covered RSPs (DD1-RSPs) to DC-containing solution. Results suggest that DC was quickly adsorbed onto RSPs and the adsorbed DC was subsequently biotransformed by the DD1 cells on RSPs. The adsorption of DC to DD1-RSPs can be well described using the pseudo-second-order kinetics and the Langmuir isotherm. The DD1 cells on RSPs converted DC to several biotransformation products through a series of demethylation, dehydration, decarbonylation, and deamination. This study demonstrated that adsorption and biotransformation could work synergistically to remove DC from water.
研究领域:
环境科学
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微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
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2026
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IF 7.9
Aishu Li,Penggang Li,Hao Xu,Zhenzhou Zhang,Qi Liao,Weichun Yang,Qingzhu Li,Mengying Si,Nan Hu,Guangyue Li,Zhihui Yang
Synergistic mineralization is a new remediation method for dealing with multi-metal(loid)s pollutants. Here, a novel remediation strategy of enhanced synergistic mineralization of Uranium (U), Arsenic (As), and Cadmium (Cd) in U tailings pond wastewater through bio-oxidation of As(III) by Brevundimonas spp was proposed. A novel strain of As(III)-oxidizing bacteria ( Brevundimonas ) with highly resistant to U, As, and Cd was isolated. One biological removal test group was set with U-As(III)-Cd (UAs III Cd- Brevundimonas ), and two chemical removal test groups composed of U-As(V)-Cd (UAs V Cd), and U-As(III)-Cd (UAs III Cd), respectively. The results showed that A(V) in the UAs V Cd group could combine with U and Cd to enhance their removal rates and promote synergistic mineralization to form the more stable precipitations (Cd(UO 2 ) 2 (AsO 4 ) 2 ·nH 2 O) compared to As(III). Further, We achieved biological oxidation of As(III) to A(V) by isolated As(III)-oxidizing bacteria Brevundimonas , which contributed to the subsequent synergistic mineralization of U and Cd to form precipitates similar to those in chemical methods (UAs V Cd group), ultimately increasing the removal of U, As, and Cd by 5.90, 2.40, and 6.19 times than without adding Brevundimonas spp. The results will help to design more effective bioremediation strategies for U-As-Cd multi-metal(loid)s contamination. Download: Download high-res image (198KB) Download: Download full-size image
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）