1株产α-半乳糖苷酶乳球菌的分离鉴定及酶学特性  

Screening of a strain of Lactoccus that produce of α-galactosidase and the enzymatic characteristics analysis

作　　者：周晶辉[1] 胡超[1] 刘晓柱[1] 彭珍子[1] 张学文[1] 

机构地区：[1]湖南农业大学生物科学技术学院,湖南长沙410128

出　　处：《湖南农业大学学报（自然科学版）》2011年第1期22-25,共4页Journal of Hunan Agricultural University(Natural Sciences)

基　　金：湖南省科学技术厅项目(01JZY2099)

摘　　要：从湘西富含豆粕下脚料土壤中筛选鉴定出1株产α-半乳糖苷酶细菌,对其进行显微形态观察、分子生物学鉴定及酶学特性分析。结果表明,该细菌为球形细菌,革兰氏染色阳性,16S rDNA序列与乳球菌有98%的同源性,可以确定为乳球菌属。细菌产分泌性α-半乳糖苷酶,其胞外α-半乳糖苷酶摇瓶发酵液初酶活为6.21 U/mL,在45℃、pH 5.5时该酶活性表现为最大值。酶的表达受D-棉籽糖的诱导和葡萄糖的抑制,当D-棉籽糖的浓度为30μmol/mL时诱导效果最佳,当葡萄糖浓度为30μmol/mL时对该酶的合成有较明显的抑制作用,表现为糖代谢操纵元的典型调控方式。A strain of α-galactosidase producing bacterium was screened out from the soil rich in soybean wastes of Western Hunan.The bacterium morphology observation,molecular biological identification and enzymatic characteristics was analysed.The bacterium was a stained gram positive and its 16S rDNA had homology with Lactoccus.It was identified as a strain bacterium of Lactoccus family.The bacteria produced an excretive α-galactosidase.The maximal α-galactosidase activity of shaking cultured supernatant was 6.21 U/mL.The α-galactosidase showed the enzyme activity was the biggest with the value of pH5.5 and the tempertured of 45 ℃.The enzyme gene must be regulated in the typical glycolytic operon modle that the enzyme production could be induced by the substrate and inhibited by glucose.The best induction effect was obtained when the D-raffinose concentration reached 30 μmol/mL and it was inhibited when glucose concentration reached 30 μmol/mL.

关 键 词：α-半乳糖苷酶乳球菌 筛选 鉴定 酶学特性 

分 类 号：S154.3[农业科学—土壤学]