土壤耐硒菌株筛选及其硒活化能力评价研究

Screening of Selenium-resistant Strains in Soil and Evaluation of Selenium Activation Ability

【目的】从湖北省恩施市双河镇新塘乡渔塘坝硒矿床采集矿渣、淤泥、农田土壤,从中筛选分离出耐硒菌株,并对筛选出菌株的活化土壤硒的能力进行评价。【方法】采用稀释涂布平板法和平板划线法分离、筛选出耐受亚硒酸钠浓度较高的菌株,根据菌株形态学特征和用分子生物学方法对其进行分类鉴定,再将分离得到的耐硒菌株分别接种于酸性富硒赤红壤中进行培养,通过测定培养后土壤中的硒含量评价两菌株活化土壤硒的能力。【结果】筛选出了细菌B-1和真菌B-2两耐硒菌株;细菌B-1被鉴定为嗜麦芽寡养单胞菌(Stenotrophomonas maltophilia),其可耐亚硒酸钠浓度为17000μg mL^(−1),在温度20~35℃、pH 5~9、盐浓度0~3%条件下可正常生长;真菌B-2被鉴定为聚多曲霉(Aspergillus sydowii),该菌株可耐亚硒酸钠浓度为6000μg mL^(−1),在温度25~30℃、pH 4~7、盐浓度2%~5%条件下可正常生长。添加两耐硒菌株培养后土壤的可溶态硒和可交换态硒含量均显著提高。【结论】筛选出具有较高的硒耐受性和较强的活化酸性富硒土壤中硒的能力的菌株,可为富硒土壤资源开发利用提供生物种质资源和技术手段,对富硒微生物肥料研发、富硒农产品生产和硒污染土壤环境修复也有重要意义。

[Objectives]Selenium(Se)-resistant strains were isolated from the slag,silt and farmland soil of the Xintang Township,Shuanghe Town,Enshi,Hubei Province.And the ability of the selected strains to activate soil Se was evaluated.[Methods]Using the dilution coating plate method and the plate dashing method,the strains with higher sodium Se resistance were isolated and screened.Classification and determination were carried out by morphological characteristics and molecular biology methods.The isolated Se-tolerant strains were then inoculated in acid Se-rich red soil for culture,and the ability of the two strains to activate soil Se was evaluated by measuring the Se content in the soil after the culture.[Results]Two Se-resistant strains of bacteria B-1 and fungal B-2 were screened.Bacteria B-1 were identified as Stenotrophomonas maltophilia,which has a concentration of 17000μg·mL^(−1).It could grow normally when the temperatures was 20-35℃,the pH was 5-9,and the NaCl mass fraction was 0%-3%.Fungus B-2 was identified as Aspergillus sydowii,which has a concentration of 6000μg mL^(−1).It could grow normally when the temperatures was 25-30℃,the pH was 4-7,and the NaCl mass fraction was 2%-5%.After the addition of two Seresistant strains for culture,and the content of soluble Se and exchangeable Se in the soil were significantly increased.[Conclusions]The two strains selected showed high Se tolerance and had good activity of Se in acid Se-rich soil.The availability of Se-resistant strain resources could provide biological species resources and technical means for the development and utilization of Se-rich soil resources.It is also of great significance in the research and development of Se-rich microbial fertilizers,the production of Se-rich agricultural products,and the environmental restoration of Secontaminated soils.