植物乳杆菌β-D-葡萄糖苷酶的定位及活性研究

以对硝基苯基β-D-葡萄糖苷为底物,通过比色法从5株植物乳杆菌中筛选出2株有较高β-D-葡萄糖苷酶酶活力的菌株,并利用差速离心分级沉淀对其β-D-葡萄糖苷酶进行定位。根据对植物乳杆菌的生长状况的分析,测定其在不同生长条件下β-D-葡萄糖苷酶的酶活力。结果表明:目的菌株体内的β-D-葡萄糖苷酶为胞内酶,属于细胞膜结合酶;该酶在对数生长末期(培养至12 h)酶活力最高,最适产酶培养基为改良MRS培养基;以完整细胞为参照对象,植物乳杆菌520、XJ-25菌株所产的β-D-葡萄糖苷酶均受纤维二糖及熊果苷的诱导,熊果苷的诱导作用较强。

Localization and Activity of β-D-Glucosidase from Lactobacillus plantarum

In this study, two strains of Lactobacillus plantarum (L. plantarum) with the highest β-D-glucosidase activity
were obtained from five L. plantarum strains with p-nitro-phenyl-β-D-glucopyranoside as the substrate and their cellular
localization of β-D-glucosidase was studied by using fractional precipitation with differential centrifugation. In addition,
the enzymatic activity of β-D-glucosidase was determined under different growth conditions, followed by analyzing the
growth of L. plantarum. Our results supported the conclusion that β-D-glucosidase was membrane-associated and might be
insoluble. The highest activity was displayed at the late exponential phase and an improved MRS was verified as the optimal
medium. For whole cells, β-D-glucosidase was induced by cellobiose and arbutin, but arbutin played more important role in
the enzymatic activity.