一株乙草胺降解菌的分离及其降解特性研究

【目的】分离获得一株能有效降解乙草胺的菌株,并研究其降解乙草胺的影响因素,为乙草胺生物修复提供微生物资源。【方法】通过富集培养和分离培养,从样品中筛选能以乙草胺为唯一碳氮源的菌株。通过划线培养获得单菌落,并采用革兰氏染色法和16S r RNA基因测序进行菌株的初步鉴定和系统分类。通过单因素试验研究初始乙草胺浓度、外加碳氮源对其降解乙草胺的影响,并基于正交设计进行优化。【结果】分离获得的一株菌为革兰氏阴性菌,初步确定为Pseudomonas sp.,能有效利用乙草胺进行生长。单因素试验证明在乙草胺初始浓度为10 mg/L时降解率最高;外加碳氮源能提高乙草胺降解率,其中葡萄糖和蛋白胨分别最为有效。正交设计表明在最优条件下,其对乙草胺降解率可以达到80.2%。【结论】菌株A-1能有效利用乙草胺进行生长,其降解乙草胺受多种因素影响。本研究将为利用进行该菌株进行乙草胺污染修复提供菌种资源。

Isolation and degradation characteristics of an acetochlor-degrading strain

Objective] This study was aimed to obtain a strain which can effectively degrade acetochlor, and to investigate the factors affecting the degradation of the herbicide, so as to provide microbial resources for acetocholor bioremediation. Methods] By enrichment and separation of culture from the sample, the pure culture was selected from the medium supplemented with acetochlor as the sole source of carbon and nitrogen. The strain in single colony was obtained by means of streak, and was preliminarily identified and classified by Gram staining and 16S rRNA gene sequencing. Effects of initial acetochlor concentration, additional sources of carbon and nitrogen on the degradation of the herbicide were studied by single factor test. Meanwhile, the effects of above-mentioned factors were optimized by orthogonal design. Results] A strain of Gram negative bacteria was isolated and identified as Pseudomonas sp. Single factor experiment demonstrated that the optimal initial acetochlor concentration for acetochlor degradation was 10 mg/L; the addition of carbon and nitrogen sources could improve the degradation rate of acetochlor. Among them, glucose and peptone was the best carbon and nitrogen source, respectively. The orthogonal design showed that the degradation rate of acetochlor could reach 80.2% under the optimum conditions. Conclusion] The strain A-1 was able to grow on acetochlor, and the degradation of the herbicide is affected by many factors. This study will provide the strain resources for acetochlor bioremediation.