肠杆菌CBY-9的筛选鉴定及释硅条件优化

Screening and Identification of Silica-releasing Microorganism CBY-9 and Optimization of Silica-releasing Condition

为了将铁尾矿中丰富的硅元素转化为有效硅,供植物利用。对铁尾矿样品中的释硅功能微生物进行分离筛选、鉴定及生长性能研究,并通过单因素和响应面试验对释硅条件进行优化。筛选出一株高效释硅菌CBY-9,经形态学、生理生化特性和16S rDNA序列分析,鉴定菌株CBY-9为阴沟肠杆菌(Enterobacter cloacae)。该菌株可以在15~40℃、NaCl浓度小于8%和pH=4~10的范围内很好生长,说明其具有很强的广适温性、耐盐性和耐酸碱性,抗逆性较强。通过单因素及响应面法优化回归模型分析表明,当温度29.98℃、接种量4.92%、铁尾矿砂添加量9%时,浸出液中有效硅含量为43.37 mg/L,与理论值仅相差0.28%,说明所建模型与实际情况拟合良好。研究结果可以为土壤改良、铁尾矿区土壤生态复垦及铁尾矿资源化利用提供新的菌种资源和技术指导。

In order to convert the abundant silica of iron tailings into available silica so that it can be used by plants,this study was conducted to isolate,screen,identify and examine the growth performance of silica-releasing functional microorganisms from iron tailings samples,and optimize the silica-releasing conditions by single-factor and response surface experiments.The results showed that an efficient silica-releasing strain was screened and identified as Enterobacter cloacae(CBY-9)by morphology,physiological and biochemical characteristics and 16S rDNA sequence analysis.Strain CBY-9 can grow well in the range of 10~40℃,NaCl concentration lower than 8%and pH=4~10,indicating that has great broad temperature tolerance,salt tolerance and acid-base tolerance,and has a higher resistance to adversity.The optimal values of the three significant factors were determined by single-factor and response surface optimization regression models:leaching temperature of 29.98℃,inoculum of 4.92%,and tailings concentration of 9%,at which the active silicon concentration in the leachate was 43.37 mg/L,only 0.28%different from the theoretical value.This study provides new strain resources and technical guidance for soil improvement,soil experiment ecological reclamation in iron tailings areas and resource utilization of iron tailings.