耐镉促生根瘤菌的鉴定及其对镉的吸附特性

池耀威; 王晓雅; 初少华; 周培; 张丹

文章摘要

池耀威,王晓雅,初少华,周培,张丹.耐镉促生根瘤菌的鉴定及其对镉的吸附特性[J].农业环境科学学报,2021,40(4):791-800.

耐镉促生根瘤菌的鉴定及其对镉的吸附特性

Identification of a cadmium-tolerant and growth-promoting Rhizobium strain and characterization of its adsorption properties for cadmium

投稿时间：2020-08-19

DOI：10.11654/jaes.2020-0975

中文关键词: 镉农田土壤生物修复根瘤菌耐受性吸附

英文关键词: cadmium farmland soils bioremediation Rhizobium pusense tolerance adsorption

基金项目:上海市科技兴农推广项目（沪农科推字（2017）第2-1号）；国家自然科学基金项目（31702003）；上海市晨光计划项目（17CG07）

作者	单位	E-mail
池耀威	上海交通大学农业与生物学院, 上海 200240
王晓雅	上海交通大学农业与生物学院, 上海 200240
初少华	上海交通大学农业与生物学院, 上海 200240
周培	上海交通大学农业与生物学院, 上海 200240
张丹	上海交通大学农业与生物学院, 上海 200240	zhdsjtu@sjtu.edu.cn

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中文摘要:

微生物在镉（Cd）污染农田土壤的生物修复上具有应用潜力，然而目前仍缺少有价值的微生物，且从种类繁多的微生物群体中鉴定出有价值的Cd生物修复候选者具有一定挑战性。以前期筛选获得的植物生长促进微生物AXY1菌株为研究对象，通过形态特征和系统发育学分析对该菌株进行初步鉴定，并对其生长条件进行优化，进一步考察其对Cd的耐受、吸附和活化特性。经鉴定该菌株为根瘤菌（Rhizobium pusense），最适生长温度在35℃左右，最适生长pH在7.0左右；菌株对Cd的耐受性达120 mg·L^-1，对碳酸镉的活化率为9.21%。批次吸附实验结果显示，在pH 7.0、生物量为1.0 g·L^-1（湿质量）、初始Cd²⁺浓度为10 mg·L^-1和吸附时间4 h条件下，菌株表现出最高的吸附率41.98%。等温线模型拟合结果显示，菌株的吸附数据符合Langmuir模型，表明菌株以单层生物吸附为主。解吸实验结果显示，菌株以离子交换形式（46.94%）为主对Cd²⁺进行吸附。SEM-EDS和FTIR分析结果显示，在吸附过程中，Cd²⁺可能与菌株表面配体（—OH、—NH、—COOH等）发生相互作用。该研究结果表明，AXY1菌株具有较高的Cd耐性和吸附特性，可用于Cd污染农田土壤的生物修复。

英文摘要:

Microorganisms have application potential in the bioremediation of cadmium-contaminated farmland soils. However, there is still a shortage of valuable microorganisms, and it is challenging to identify valuable candidates for cadmium bioremediation from a variety of microorganisms. In this study, the cadmium tolerance, adsorption capability, and activation capability of the plant growth-promoting microorganism AXY1 were investigated. The strain was identified as Rhizobium pusense through morphological and phylogenetic analysis, the optimum growth temperature was approximately 35℃, and the optimum growth pH was approximately 7.0. The minimal inhibitory concentration(MIC) value of the strain to cadmium was 120 mg·L^-1, and the activation rate of cadmium carbonate was 9.21%. Batch adsorption experiments showed that at a pH of 7.0, biomass dosage of 1.0 g·L^-1(wet weight), initial Cd²⁺ concentration of 10 mg·L^-1, and adsorption time of 4 h, the strain showed the highest adsorption rate of 41.98%. The Langmuir isotherm model was well fitted using the data obtained from strain AXY1, thereby indicating that the strain mainly conducted monolayer biosorption. Desorption experiments showed that the strain mainly adsorbed Cd²⁺ by ion exchange(46.94%). Furthermore, FTIR and SEM-EDS analyses revealed the probable interactions of Cd²⁺ with the strain surface ligands, such as -OH, -NH, and -COOH, during surface adsorption. The results reveal that strain AXY1 has high cadmium tolerance and adsorption characteristics, which can be used for the bioremediation of cadmium-contaminated farmland soil.

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