同步异养硝化好氧反硝化细菌Acinetobacter sp.TAC-1的氮代谢途径研究  

New insight into the nitrogen metabolism pathway of simultaneous heterotrophic nitrification-aerobic denitrification bacteria Acinetobacter sp.TAC-1

作　　者：高艳辉 谭娜[2] 赵天涛 张云茹[2] 张千[2] 彭绪亚 艾铄[3] GAO Yanhui;TAN Na;ZHAO Tiantao;ZHANG Yunru;ZHANG Qian;PENG Xuya;AI Shuo(College of Environment and Ecology,Chongqing University,Chongqing 400044,China;College of Chemistry and Chemical Engineering,Chongqing University of Technology,Chongqing 400054,China;Chongqing Shiji Eco-environmental Science and Technology Co.,Ltd.,Chongqing 404100,China)

机构地区：[1]重庆大学环境与生态学院,重庆400044 [2]重庆理工大学化学化工学院,重庆400054 [3]重庆士继生态环境科技有限公司,重庆404100

出　　处：《重庆理工大学学报（自然科学）》2022年第1期204-214,共11页Journal of Chongqing University of Technology：Natural Science

基　　金：国家自然科学基金项目(51978117,51908099),重庆市技术创新与应用示范项目(cstc2019jscx-msxmX0418,cstc2020jscx-msxmX0040),重庆市巴南区科技规划项目(2020QC380)。

摘　　要：为阐明分离自重庆某生猪养殖企业畜禽粪污沼液的一株高效同步异养硝化好氧反硝化(simultaneous heterotrophic nitrification and aerobic denitrification,SND)脱氮菌株Acinetobacter sp.TAC-1的氮代谢途径,分别考察TAC-1菌株DNA水平上的氮代谢基因序列特征和mRNA水平上氮代谢基因差异表达。首先,通过T-A克隆和Sanger测序定性分析TAC-1菌株的SND氮代谢基因,确认DNA水平上TAC-1菌株存在SND过程硝酸盐还原酶调控基因narG,亚硝酸还原酶调控基因nirK及nirS,并发现羟胺氧化过程在TAC-1菌株中可能为新的脱氮途径。其次,结合不同氮源(NH_(4)^(+)-N,NO_(3)^(-)-N及NO_(2)^(-)-N)培养条件下TAC-1菌株不同生长阶段的氮代谢特性、产物分析和过程中的narG、nirK及nirS在mRNA水平上的差异表达分析证实了TAC-1菌株的SND氮代谢途径,反硝化过程中nirK和nirS负责NO_(2)^(-)-N的解毒,硝酸盐还原是由narG型硝酸盐还原酶介导的。因此,该研究从氮代谢基因及其差异表达视角深化了对SND细菌氮代谢机制的认识,为SND细菌的改造和同步硝化反硝化脱氮工艺的开发提供理论依据。To clarify the nitrogen metabolic pathway of a simultaneous heterotrophic nitrification and aerobic denitrification(SND)strain of Acinetobacter sp.TAC-1 isolated from livestock and poultry manure sewage from a pig breeding enterprise in Chongqing.The nitrogen metabolism genes sequence at DNA level and their differential expression at mRNA level of strain TAC-1 were respectively explored.Firstly,T-A cloning and sanger sequencing for nitrogen metabolic genes in strain TAC-1 revealed the existence of genes(nitrate reductase regulating gene of narG,nitrite reductase regulating genes of nirK and nirS)involved in SND pathway at DNA level.Additionally,the hao gene sequence showed that there might be a new nitrification pathway in strain TAC-1 during the hydroxylamine oxidation process.Furthermore,the metabolism capability of different N-source,metabolism product,and the differential expression of SND genes(narG、nirK and nirS)at mRNA level were jointly analyzed during the growth process of strain TAC-1,which was separately cultured with (NH_(4)^(+)-N,NO_(3)^(-)-N and NO_(2)^(-)-N) as N-source.Results indicated that nirK and nirS provide an adequate capacity for NO_(2)^(-)-N detoxification,and the dominant nitrate reduction is mediated by narG-type nitrate reductase during denitrification processes.Therefore,this study provides valuable insights into the nitrogen metabolic pathway in SND strain from the perspective of the nitrogen metabolic genes and their differential expression,which is favorable for genetic modification of SND bacteria and the development of SND technology.

关 键 词：氮代谢途径 不动杆菌 同步异养硝化好氧反硝化 mRNA表达 

分 类 号：X172[环境科学与工程—环境科学]