摘要
六价铬[Cr(Ⅵ)]是一种毒性很强的重金属污染物,严重威胁环境和人类健康。为了获得性能优良的Cr(Ⅵ)污染处理菌株,研究基于不同来源的铬还原酶,以大肠杆菌为模式菌株,通过基因工程技术构建铬还原酶的过表达菌株,并通过Cr(Ⅵ)抗性和还原能力分析探究过表达菌株的Cr(Ⅵ)污染处理性能。结果显示,过表达E.coli来源的铬还原酶NfsA与高活性突变蛋白NfsA(L124A),以及P.putida来源的ChrR均能增强菌株的Cr(Ⅵ)抗性,从强到弱依次为oeNfsA(L124A)、oeNfsA、oeChrR、野生型(Wild-Type,WT)。相较于WT,oeNfsA和oeChrR在前2 h内的Cr(Ⅵ)还原能力提升约3倍,而oeNfsA(L124A)不仅能够耐受50 mg/L Cr(Ⅵ),且在10 h内对其还原率接近100%。研究不仅能为基因工程菌在Cr(Ⅵ)污染处理领域中的应用奠定基础,还为生物修复法处理Cr(Ⅵ)污染领域拓展了研究思路。
Hexavalent chromate[Cr(Ⅵ)]is a highly toxic heavy metal pollutant that poses a significant threat to both the environment and human health.To develop strains with enhanced performance in Cr(Ⅵ)resistance and reduction,chromate reductases from various sources were overexpressed in Escherichia coli(E.coli)BL21 using genetic engineering techniques.The overexpression strains,oeNfsA and oeChrR,which overexpressed NfsA from E.coli and ChrR from Pseudomonas putida,were first constructed and screened.To enhance the enzyme activity of NfsA,the nfsA gene underwent random mutation through error-prone PCR,resulting in the identification of the NfsA(L124A)mutant,which exhibited improved Cr(Ⅵ)reduction activity.By examining the resistance and reduction capabilities of the engineered bacteria to Cr(Ⅵ),the metabolic characteristics of Cr(Ⅵ)in the overexpression strains oeNfsA,oeNfsA(L124A),and oeChrR were explored.The results indicated that all three overexpression strains enhanced resistance to Cr(Ⅵ).However,there were notable differences in their resistance abilities,with the order of effectiveness being oeNfsA(L124A),followed by oeNfsA,and then oeChrR.The Cr(Ⅵ)reduction ability of the overexpression strains was significantly enhanced compared to the Wild-Type(WT)strain.Within the first 2 hours,the Cr(Ⅵ)reduction capabilities of oeNfsA and oeChrR increased by approximately threefold in comparison to WT.Notably,the mutant strain oeNfsA(L124A)exhibited exceptional performance;it not only tolerated a high concentration of 50 mg/L of Cr(Ⅵ)but also achieved a reduction rate approaching 100%within 10 hours.These findings offer valuable insights into the potential application of genetically engineered bacteria for Cr(Ⅵ)pollution treatment.The enhanced Cr(Ⅵ)resistance and reduction capabilities of the overexpression strains indicate that they could serve as promising candidates for bioremediation efforts.Additionally,this research broadens the scope of bioremediation strategies for Cr(Ⅵ)pollution,providing new ideas and approaches for future studies.
作者
闫花朵
张留杰
张佳慧
王梦真
侯文静
潘春梅
YAN Huaduo;ZHANG Liujie;ZHANG Jiahui;WANG Mengzhen;HOU Wenjing;PAN Chunmei(College of Food and Biological Engineering,Henan University of Animal Husbandry and Economy,Zhengzhou 450000,China)
出处
《安全与环境学报》
北大核心
2025年第9期3653-3661,共9页
Journal of Safety and Environment
基金
国家自然科学基金青年基金项目(32100085)
河南牧业经济学院博士启动基金项目(M4050007)。
关键词
环境工程学
Cr(Ⅵ)
铬还原酶
过表达菌株
environmental engineering
Cr(Ⅵ)
chromate reductase
overexpression strains
