一株高效还原亚硒酸盐的粘质沙雷氏菌的分离鉴定及特性

Isolation,Identification and Characterization of A Serratia marcescens with High Selenite Reduction Efficiency

从广西钦州市钦北区的富硒土壤中筛选出一株可高效还原亚硒酸盐的细菌QZB-1。16S rDNA基因序列分析确定菌株为粘质沙雷氏菌(Serratia marcescens)。研究发现菌株QZB-1可耐高达180 mmol/L的亚硒酸盐。进一步研究发现菌株QZB-1在36 h之内对1 mmol/L亚硒酸盐的还原率为95%,随着硒浓度升高还原率有所下降。正交实验表明,对菌株还原亚硒酸盐的影响程度依次是初始亚硒酸盐浓度>培养时间>接种量,最佳还原条件是初始亚硒酸盐浓度为1 mmol/L,接种量为10%,培养时间为36 h,此时菌株QZB-1对亚硒酸盐的还原率大于98.55%。研究结果表明新型亚硒酸盐还原菌粘质沙雷氏菌QZB-1可高效还原亚硒酸盐为单质纳米硒,可高效应用于亚硒酸盐污染水体和土壤的治理。

A bacterium strain QZB-1 with high selenite reduction efficiency was isolated from Se-rich soil in Qinbei District of Qinzhou City,Guangxi Province.The strain was identified as Serratia marcescens through 16S rDNA gene sequence analysis.The results revealed that the strain could tolerate selenite concentration as high as 180 mmol/L.Further study suggested that the strain QZB-1 could reduce 95%of 1 mmol/L selenite within 36 hours,and selenite reduction rate decreased with the increase of selenite concentration.The orthogonal experiment indicated that the rank of influence degree by selenite reduction was initial selenite concentration>incubation time>inoculum.The optimal conditions for selenite reduced were as following:initial selenite concentration 1 mmol/L,inoculation volume 10%,and incubation time 36 hours.Under these conditions,selenite reduction rate was more than 98.55%.The findings suggested that the novel selenite reducing strain Serratia marcescens QZB-1 can efficiently reduce selenite to elemental selenium nanoparticles,and can be effectively applied in the bioremediation of selenite polluted soil and water.