二甲戊灵降解菌的筛选及降解效果评价

发布时间：2018-01-14 10:45

  本文关键词：二甲戊灵降解菌的筛选及降解效果评价　出处：《石河子大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 二甲戊灵 降解菌 沙雷氏菌 假单胞菌 培养基 土壤

【摘要】：二甲戊灵是二硝基苯胺类选择性土壤处理除草剂,在新疆普遍应用于棉田进行土壤处理,二甲戊灵的大量施用严重毁坏了土壤中的微生物系统,影响土壤质量。本研究利用土壤中多样的微生物类群、采用富集培养的方法,定向筛选新疆棉田土壤中二甲戊灵的高效降解细菌,研究其降解特征,探索其降解条件和降解效率,为新疆棉田二甲戊灵污染土壤的治理与修复提供理论基础和技术支持。1.采用富集培养法从新疆的棉田土壤中筛选二甲戊灵高效降解菌株,经平板法初筛获得9株高度耐受且具备降解能力的细菌菌株,采用气相色谱法对其降解能力进行检测,确定了2株高效降解菌,命名为JY-2和JY-5,3 d内对200 mg/L二甲戊灵的降解效率在70%以上,9 d内对500 mg/L二甲戊灵的降解效率达90%以上;2.通过常规形态学鉴定和16S rDNA序列分析对其鉴定,鉴定的结果为:菌株JY-2为沙雷氏菌(Serratia sp.),菌株JY-5为假单胞菌(Pseudomonas sp.);3.在培养基环境中,研究了降解菌株的降解条件。该2株细菌能够在二甲戊灵作为唯一碳源的无机盐培养基中生长,在蔗糖浓度0.5%、接种量体积10%、初始二甲戊灵浓度200 mg/L、pH 7.0、温度30℃培养环境中振荡培养3 d,二甲戊灵的降解率分别可达83.34%和82.79%;4.以细菌JY-2和JY-5为供试菌株,实验室条件下,研究其对二甲戊灵污染土壤的修复作用及其影响因素,结果表明,二甲戊灵的降解率与接种量呈正相关,其中,细菌JY-2或JY-5的接种量为10%(0.6×109 cfu·g-1土)时,对土壤中200 mg/kg二甲戊灵15 d后降解率可达66.18%和65.66%,低于此浓度,降解菌的降解作用较弱;此外,土壤温度及含水量对菌株降解也产生了显著的影响,研究表明,土壤中适宜的降解温度为30℃,含水量为600 g/kg;5.采用生物法对菌株的降解效率进行验证,药剂处理组玉米和棉花出苗率为33.33%和71.11%,投入二甲戊灵降解菌后,土壤中二甲戊灵浓度降低,玉米出苗率提高到55.56%和67.78%,棉花出苗率增加到88.89%和91.11%,均差异显著。接种细菌JY-2和JY-5可不同程度减轻土壤中二甲戊灵对玉米和棉花的生长抑制作用,具有一定的土壤修复能力。
[Abstract]:Penicillin is a selective herbicide for soil treatment of dinitroaniline, which is widely used in cotton fields in Xinjiang for soil treatment. The extensive application of penicillin has seriously destroyed the microbial system in soil. In this study, we used a variety of soil microbial groups, using enrichment culture method, targeted screening of high-efficient degradation bacteria in Xinjiang cotton field soil, and studied its degradation characteristics. To explore the degradation conditions and degradation efficiency. To provide theoretical and technical support for the treatment and remediation of the contaminated soil in Xinjiang cotton field. 1. Screening the high-efficient degrading strains of penicillin from cotton soil in Xinjiang by enrichment culture method. Nine strains of bacteria with high tolerance and biodegradability were obtained by plate method. The biodegradability of 9 strains was detected by gas chromatography, and two strains of highly efficient biodegradable bacteria were identified, named JY-2 and JY-5. In 3 days, the degradation efficiency of 200 mg/L dimethylpentalin was more than 70% and the degradation efficiency of 500 mg/L dimethyl pentyl reached more than 90% in 9 days. 2. The results of routine morphological identification and 16s rDNA sequence analysis showed that the strain JY-2 was Serratia Shareh sp.). The strain JY-5 was Pseudomonas sp. 3. The degradation conditions of the degrading strains were studied in the medium environment. The two strains were able to grow in the inorganic salt medium with dimethylpentalin as the sole carbon source and the sucrose concentration was 0.5%. The inoculation volume was 10: 10, the initial concentration of dimethylpentalin was 200 mg / L ~ (-1) pH 7.0, the temperature was 30 鈩，

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