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厌氧E-MBR反应器在焦化废水处理中的微生物特性研究 被引量:2
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作者 杨爽 宋迪慧 +5 位作者 安路阳 张立涛 柳丽芬 屈泽鹏 徐歆未 李红欣 《微生物学报》 CAS CSCD 北大核心 2021年第8期2427-2441,共15页
【目的】将厌氧的膜生物反应器(MBR)与微生物燃料电池(MFC)耦合的厌氧电辅助膜生物反应器(E-MBR)应用于实际工业焦化废水处理。【方法】通过正交实验优化了反应器进水的培养条件为PO_(4)^(3-)14.3 mg/L、Fe^(2+)0.2 mg/L、Fe^(3+)0.1 m... 【目的】将厌氧的膜生物反应器(MBR)与微生物燃料电池(MFC)耦合的厌氧电辅助膜生物反应器(E-MBR)应用于实际工业焦化废水处理。【方法】通过正交实验优化了反应器进水的培养条件为PO_(4)^(3-)14.3 mg/L、Fe^(2+)0.2 mg/L、Fe^(3+)0.1 mg/L、Co^(2+)0.1 mg/L和Mn^(2+)0.2 mg/L。在此条件下考察了该反应器对系统中有机污染物的去除效率及厌氧污泥的污泥特性、产电性能、胞外聚合物(EPS)、微生物群落结构及膜污染的影响。【结果】结果表明,与未优化的培养条件相比,工业焦化废水COD的去除率提高了23%;污泥浓度(MLSS)、比重、沉降速度增加,污泥体积指数(SVI)降低,表明污泥颗粒化及沉降性能提高;污泥中溶解性EPS(SMP)、松散态EPS(LB-EPS)及紧密结合态EPS(TB-EPS)这3种组分中的蛋白质与多糖的比例(P/C)分别降低0.12、0.25和0.16,表明污泥更易于被降解;厌氧污泥的产电性能增强;高通量分子测序结果表明,反应器中污泥的群落结构发生了明显的变化,优势菌群突出;经扫描电镜(SEM)对比结果表明,反应器阴极膜的污染情况也得到了一定的减缓。【结论】优化进水培养条件可以达到使反应器污水处理效率提高、清理周期缩短和运行更稳定等效果,对于工业废水处理技术的节能环保方面提供一定的理论依据。 展开更多
关键词 厌氧电辅助膜生物反应器 正交优化实验 污泥特性 导电性能 微生物群落结构 膜污染
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Structure-guided manipulation of the regioselectivity of the cyclosporine A hydroxylase CYP-sb21 from Sebekia benihana 被引量:1
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作者 Fengwei Li Li Ma +8 位作者 Xingwang Zhang Jingfei Chen Feifei Qi Yinyue Huang zepeng qu Lishan Yao Wei Zhang Eung-Soo Kim Shengying Li 《Synthetic and Systems Biotechnology》 SCIE 2020年第3期236-243,共8页
The cytochrome P450 enzyme CYP-sb21 from the rare actinomycete Sebekia benihana is capable of hydroxylating the immunosuppressive drug molecule cyclosporine A(CsA)primarily at the 4th N-methyl leucine(MeLeu4),giving r... The cytochrome P450 enzyme CYP-sb21 from the rare actinomycete Sebekia benihana is capable of hydroxylating the immunosuppressive drug molecule cyclosporine A(CsA)primarily at the 4th N-methyl leucine(MeLeu4),giving rise toγ-hydroxy-N-methyl-L-Leu4-CsA(CsA-4-OH).This oxidative modification of CsA leads to dramatically reduced immunosuppressive activity while retaining the hair growth-promoting side-effect,thus demonstrating great application potential in both pharmaceutical and cosmetic industries.However,this P450 enzyme also hydroxylates CsA at the unwanted position of the 9th N-methyl leucine(MeLeu9),indicating that the regioselectivity needs to be improved for the development of CsA-4-OH into a commercial hair growth stimulator.Herein,we report the crystal structure of CYP-sb21 in its substrate-free form at 1.85Å.Together with sequence and 3D structure comparisons,Autodock-based substrate docking,molecular dynamics(MD)simulation,and site-directed mutagenesis,we identified a number of key residues including R294,E264,and M179 that can improve catalytic efficiency or change the regioselectivity of CYP-sb21 towards CsA,setting the stage for better enzymatic preparation of CsA-4-OH.This study also provides new insights into the substrate recognition and binding mechanism of P450 enzymes that accommodate bulky substrates. 展开更多
关键词 Cytochrome P450 monooxygenase Crystal structure Cyclosporine A Regioselectivity Hair growth stimulator
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