ENVIRONMENTAL POLLUTION
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2020
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IF 6.793
Kai Sun,Xing Cheng,Jialin Yu,Luojian Chen,Jiajun Wei,Wenjun Chen,Jun Wang,Shunyao Li,Qingzhu Liu,Youbin Si
Estrogens, which are extensive in the eco-environments, are a category of high-toxic emerging contaminants that induce metabolic disorders and even carcinogenic risks in wildlife and humans. Here we investigate whether fungus-secreted laccase can be used as a green catalyst to eliminate a representative estrogen, 17 β -estradiol (E2). A white-rot fungus Trametes hirsuta La-7 with high laccase-productivity, was isolated from pig manure-contaminated soil. Extracellular laccase activity expressed by strain La-7 was 65.4 U·mL −1 for a 3 d inoculation under the optimal fermentation parameters. The concentrated-crude laccase from Trametes hirsuta La-7 (CC- Th Lac) was capable of effectively metabolizing E2 at pH 4–6, and the apparent pseudo first-order reaction rate constant and half-life values were respectively 0.027–0.055 min −1 and 25.86–12.67 min ( R 2 > 0.98). The mass measurement of high-resolution mass spectrometry in combination with 13 C-isotope labeling identified that the main by-products of E2 metabolism were dimers, trimers , and tetramers, which are consistent with radical-driven C–C and/or C–O–C covalent coupling pathway, involving the initial enzymatic production of phenoxy radical intermediates and then the successive oxidative-oligomerization of radical intermediates. The formation of oligomers dramatically reduced the estrogenic activity of E2. Additionally, CC- Th Lac also exhibited high-efficiency metabolism capability toward E2 in the natural water and pig manure, with more than 94.4% and 91.0% of E2 having been metabolized, respectively. These findings provide a broad prospect for the clean biotechnological applications of Trametes hirsuta La-7 in estrogen-contaminated ecosystems.
研究领域:
环境生物学
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生物化学
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生态学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL POLLUTION
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2023
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IF 8.9
Jie Liu,Kai Sun,Rui Zhu,Xun Wang,Michael Gatheru Waigi,Shunyao Li
Bisphenol A (BPA) is a ubiquitous endocrine disruptor that poses adverse human health risks. Herein, biotransformation kinetics, products, and mechanisms of BPA undergoing a laccase-producing Trametes hirsuta La-7 metabolism were for the first time reported. Strain La-7 could completely biotransform ≤0.5 mmol·L −1 BPA within 6 d in vivo . Notably, its extracellular crude laccase solution (ECLS) and intracellular homogenized mycelium (HM) only required 6 h to convert 85.71% and 84.24% of 0.5 mmol·L −1 BPA in vitro , respectively. The removal of BPA was noticeably hampered by adding a cytochrome P-450 inhibitor (piperonyl butoxide) in HM, disclosing that cytochrome P-450 monooxygenase participated in BPA oxidation and metabolism. BPA intermediates were elaborately identified by high-resolution mass spectrometry (HRMS) combined with 13 C stable isotope ratios (BPA: 13 C 12 -BPA = 0.25: 0.25, molar concentration). Based on the accurate molecular mass, isotope labeling difference, and relative intensity ratio of product peaks, 6 versatile metabolic mechanisms of BPA, including polymerization, hydroxylation, dehydration, bond cleavage, dehydrogenation , and carboxylation in vivo and in vitro , were confirmed. Germination index values revealed that inoculating strain La-7 in a BPA-contaminated medium presented no phytotoxicity to the germinated radish ( Raphanus sativus L.) seeds. In vivo , Mg 2+ , Fe 2+ , Fe 3+ , and Mn 2+ were conducive to BPA removal, but Cd 2+ and Hg 2+ significantly obstructed BPA elimination. Additionally, strain La-7 also exhibited high-efficiency metabolic ability toward estrone (E1), 17 β -estradiol (E2), and 17 α -ethinylestradiol (EE2), with more than 96.13%, 96.65%, and 100% of E1, E2, and EE2 having been converted, respectively. Our findings provide an environmentally powerful laccase-producing fungus to decontaminate endocrine disruptor-contaminated water matrices by radical polymerization and oxidative decomposition.
研究领域:
环境科学
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微生物学
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毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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