铬还原菌Microbacterium sp.CR-H4的还原性能和机制探究  

Bioreduction performances and mechanisms of Cr(Ⅵ) by Microbacterium sp.CR-H4

作　　者：陶澳敏 陈杰 陈璐西 陆凌云 徐婷婷 金锐 何云峰[1] TAO Aomin;CHEN Jie;CHEN Luxi;LU Lingyun;XU Tingting;JIN Rui;HE Yunfeng(College of Environment and Resources,Zhejiang University,Hangzhou 310058;Hangzhou Bosheng Environmental Protection Technology Co.,LTD,Hangzhou 310010)

机构地区：[1]浙江大学环境与资源学院,杭州310058 [2]杭州博盛环保科技有限公司,杭州310010

出　　处：《环境科学学报》2024年第4期285-295,共11页Acta Scientiae Circumstantiae

基　　金：国家重点研发计划(No.2018YFC1802203)。

摘　　要：从某铬污染土壤中分离出来的铬还原菌Microbacterium sp.CR-H4具有较高的Cr(Ⅵ)还原能力,本研究对其在不同培养条件下对Cr(Ⅵ)的还原性能和还原机制进行了探究.结果表明:菌株CR-H4在较宽的初始pH(7~10)、温度(20~40℃)和Cr(Ⅵ)浓度(50~400 mg·L^(-1))范围条件下均能生长良好,并能有效还原Cr(Ⅵ).100 mg·L^(-1 )Fe^(3+)和Cu^(2+)的存在增强了菌株CR-H4的还原效率,而Zn^(2+)、Ni^(2+)、H_(2)PO_(3)^(-)则抑制了其还原能力.甘油、乳酸钠和葡萄糖均能作为电子供体促进CR-H4对Cr(Ⅵ)的还原.此外,细胞变性结果表明,CR-H4对Cr(Ⅵ)的去除主要通过酶还原而非吸附作用.细胞质组分对Cr(Ⅵ)的去除率为44.8%,显著高于细胞膜组分,表明Cr(Ⅵ)的还原主要发生在细胞内,由胞内还原酶介导.还原48 h后的Cr主要以可溶性Cr(Ⅲ)形式分布在细胞外悬浮液(94%)中,少量在细胞内累积(6%).以上研究结果可为Cr(Ⅵ)污染环境的微生物修复应用提供理论依据.The chromium-reducing bacterium Microbacterium sp.CR-H4 isolated from a chromium-contaminated soil exhibited high Cr(Ⅵ) reduction capacity.In this study,the Cr(Ⅵ) reduction performance under different culture conditions and possible reducing mechanism of Microbacterium sp.CR-H4 were investigated.The results showed that Microbacterium sp.CR-H4 could grow well under a wide range of initial pH(7~10),temperature(20~40 ℃) and Cr(Ⅵ) concentration(50~400 mg·L^(-1)),and was able to reduce Cr(Ⅵ) efficiently.The presence of 100 mg·L^(-1 )of Fe^(3+) and Cu^(2+)enhanced the reduction efficiency of strain CR-H4,while Zn^(2+),Ni^(2+) and H_(2)PO_(3)^(-)inhibited its reducing ability.Glycerol,sodium lactate and glucose all served as electron donors to promote the reduction of Cr(Ⅵ) by CR-H4.Furthermore,the cell denaturation results indicated that the removal of Cr(Ⅵ) by CR-H4 was primarily achieved through enzymatic reduction rather than adsorption.The removal efficiency of Cr(Ⅵ) by cytoplasm fraction was 44.8%,significantly higher than that by the cell membrane fraction,suggesting that Cr(Ⅵ) reduction mainly occurred intracellularly,mediated by intracellular reductases.After 48 hours of reduction,Cr was mainly distributed in the extracellular suspension(94%) in the form of soluble Cr(Ⅲ),with a small amount accumulating intracellularly(6%).The above findings can provide theoretical basis for the application of microbial remediation of Cr(Ⅵ)-contaminated environments.

关 键 词：Cr(Ⅵ) 生物还原 微杆菌 还原性能 还原机理 

分 类 号：X172[环境科学与工程—环境科学] X53