具有降解亚硝酸盐活性的解淀粉芽孢杆菌的分离与安全性分析

摘要

A potential nitrite degrading bacterium YX01 was isolated and screened from the aquaculture sediment,and identified as Bacillus amyloliquefaciens (GenBank accession number:JX649949) through ARIS 2X bacterial automatic identification system and 16S rRNA sequence analysis.Its 16S rRNA sequence had homology of 99％-100％ with those of Bacillus sp.submitted to GenBank,and showed the closest relative to Bacillus amyloliquefaciens strain LD5 (GenBank accession number:GQ853414).The nitrite degrading bacterium YX01 with concentration of 2.0×107-2.0×109cfu/L can enhance the growth of Chlorella sp.,however when the concentration is higher than 2.0×1011cfu/L,strain YX01presented obviously inhibition effect on the Chlorella sp.growth.In addition,the IC50 of strain YX01 to Chlorella sp.and its 48h-LC50 to Daphnia magna were both above 2.0×1011cfu/L,its 96h-LC50 to Ctenopharyngodon idellus was above 2.0×1011cfu/kg body weight.Thus,strain YX01 was an avirulent strain.%从养殖污泥中分离筛选了一株优良的亚硝酸盐降解菌YX01,经ARIS 2X细菌自动鉴定系统以及16SrRNA系统发育分析,该菌株被鉴定为解淀粉芽孢杆菌(Bacillus am yloliquefaciens,GenBank登录号为JX649949),其16S rRNA序列与基因库中 芽孢杆菌属菌株的16S rRNA序列有99％～100％的同源性,而且与解淀粉芽孢杆菌菌株LD5(GenBank登录号:GQ853414)的亲缘关系最近.该亚硝酸盐降解菌YX01在浓度为2.0×107～2.0×109cfu/L时对小球藻(Chlorella sp.)生长有促进作用；在浓度大于2.0×1011cfu/L时对小球藻生长具有显著抑制作用；亚硝酸盐降解菌YX01对小球藻的半数抑制浓度(IC50)大于2.0×1011cfu/L.亚硝酸盐降解菌YX01对大型蚤(Daphnia magna)的48h-半数致死浓度(LC50)大于2.0×1011cfu/L,对草鱼(Ctenopharyngodon idellus)的96h-LC50大于2.0×1011cfu/kg.经分析,亚硝酸盐降解菌YX01为无毒菌株.