沼灌土壤17β-雌二醇专性降解菌的分离筛选及降解特性  

Isolation, screening, and degradation characteristics of 17β-estradiol obligate degradation bacteria in the soil of marsh irrigation

作　　者：余薇薇 疏明慧 谢明原 张敏讷 刘聪[2] 杨硕 万巧玲 毛羽丰 陈杰云 Yu Weiwei;Shu Minghui;Xie Mingyuan;Zhang Minne;Liu Cong;Yang Shuo;Wan Qiaoling;Mao Yufeng;Chen Jieyun(Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education,School of River and Ocean Engineering,Chongqing Jiaotong University,Chongqing 400074,China;Southwest Technology and Engineering Research Institute,Chongqing 400039,China;Chongqing Yudong Water Affairs Co.,Ltd.,Chongqing 404000,China;Chongqing Yubei District Construction Management Affairs Center,Chongqing 401120,China)

机构地区：[1]重庆交通大学河海学院水利水运工程教育部重点实验室,重庆400074 [2]西南技术工程研究所,重庆400039 [3]重庆市渝东水务有限公司,重庆404000 [4]重庆市渝北区建设管理事务中心,重庆401120

出　　处：《农业工程学报》2022年第8期218-224,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(51608079);重庆市研究生教育教学改革研究项目(yig182028);重庆市大学生创新创业训练项目(S202010618007);重庆市基础研究与前沿探索项目(cstc2018jcyjAX0322)。

摘　　要：集约化畜禽养殖场产生的沼液通常就地回用,在循环利用有机物的同时也会带来类固醇雌激素(Steroid Estrogens,SEs)的累积及污染。为降低沼灌后SEs对水土环境的污染风险,该研究采用富集和纯化培养法,对西南地区某奶牛养殖场沼灌区土壤中雌激素降解菌进行分离及筛选,获得一株利用17β-雌二醇(17β-E2)为唯一碳源生长繁殖的降解菌。通过16S rDNA基因序列进行同源性比对以确定种属,并研究其降解特性。分别研究了菌株在不同温度、pH值、底物浓度三种单因素条件下的降解特性,然后利用三因素三水平正交试验继续优化菌株最适降解条件。结果表明:分离出的优势菌为生丝微菌属(Hyphomicrobium sp.),命名为Hyphomicrobium sp.SS-1,该菌株在10~40℃、pH值为5~9、底物浓度为1~10 mg/L的条件下,均能不同程度降解17β-E2。其中菌株在温度为30℃、pH值为7、底物浓度5 mg/L的条件下,培养7d对17β-E2的降解率可达71%,并伴随毒性低于E2的降解产物E1和E3生成,总雌激素去除率为56.8%。正交试验结果显示,各因素对菌株降解能力的影响顺序从小到大为:底物浓度、温度、pH值,且都为显著影响(P<0.05);菌株最适降解条件为温度35℃、pH值为7、底物浓度5 mg/L,该条件下培养7 d,菌株对17β-E2的降解率可达97.09%。研究结果可为复杂基质环境中微生物降解SEs提供优质菌种资源,并为沼液灌溉区土壤的雌激素污染修复提供有效途径。Biogas slurry has been usually reused on-site in intensive livestock and poultry farms. It can also inevitably bring the accumulation and pollution of Steroid Estrogens(SEs) while recycling the organic matter during production. This study aims to reduce the pollution risk of SEs to the soil and water environment after biogas irrigation. The enrichment and purification were also adopted to isolate and screen the estrogen-degrading bacteria in the soil of a dairy farm in the southwest China of the biogas irrigation areas. A strain of estrogen-degrading bacteria was obtained, where the 17β-estradiol(17β-E2)was used as the only carbon source for growth and reproduction. The strain was homologated by the 16S r DNA gene sequences, further to identify the species for the subsequent 17β-E2 degradation tests. The strains were then characterized at different temperatures(10, 20, 25, 30, 35, 37, and 40 ℃), pH values(5, 6, 7, 8, and 9), substrate concentrations(1, 3, 5, 7, and 10 mg/L) degradation characteristics. A three-factor and three-level orthogonal test was continued to optimize the degradation conditions of the strain. The results show that a dominant strain isolated from the sample was identified as Hyphomicrobium sp., named Hyphomicrobium sp. SS-1. There were varying degrees of degrading the 17β-E2 under the conditions of 10-40 ℃,pH value of 5 ~ 9, and substrate concentration of 1-10 mg/L. Specifically, the degradation rate of 17β-E2 by strains showed a trend of increasing first and then decreasing, with the increase of temperature, pH value, and substrate concentration. The optimal growth temperature of the strain was achieved at 30 ℃ in the environmental temperature test, indicating that the high temperature was not conducive to the growth and metabolism of the strain. The degradation rate of 17β-E2 increased first and then decreased, with the increase in temperature, where the maximum degradation was 46.4% at 30 ℃. Furthermore, the presence of E1 and E3 estrogenic products was accompanied by the de

关 键 词：降解 微生物 17β-雌二醇(17β-E2) 生丝微菌属 降解菌 土壤污染 

分 类 号：X52[环境科学与工程—环境工程]