海洋低温葡萄糖氧化酶细菌选育及其酶学性质研究

Breed marine bacteria producing cold-active glucose oxidase and enzyme properties analysis

为获得产低温葡萄糖氧化酶(glucose oxidase,GOD)的细菌,提高其产酶能力,研究GOD酶学性质,通过平板显色法从海泥样品中筛选低温GOD生产菌株,经形态特征、生理生化鉴定及分子生物学鉴定确定菌株分类。经诱变育种获得高产GOD菌株,并对所产GOD进行酶学性质研究。研究获得1株编号8-Ⅲ的高产低温GOD细菌,鉴定为柠檬酸杆菌属(Citrobacters sp.8-Ⅲ),产GOD酶活力为0.75U/mL。经诱变得到可稳定遗传的突变菌株8-Ⅲ-a44,产GOD酶活力为1.77U/mL,为原始菌株的2.36倍。最适pH为6.5,最适作用温度为15℃,在0~35℃有较高酶活力,为低温酶。并且添加K^+、Ni^2+对GOD活性有明显促进作用。该研究为其在海产品保鲜、饲料防腐方面的应用奠定基础。

This study aimed to obtain low-temperature glucose oxidase(GOD)producing bacteria,improve their enzyme-producing ability and study the properties of GOD.The low-temperature GOD producing strains were screened from sea sediments and identified.The strain with high yield of GOD was obtained by mutation breeding,and the properties of such GOD were studied.A strain 8-Ⅲwith high yield of cold-active GOD was identified as Citrobacters sp.8-III,and the activity of the GOD was 0.75 U/mL.Moreover,a mutant strain 8-Ⅲ-a44 with high stability was obtained,the produced GOD activity was 1.77 U/mL,which was 2.36 times of that of strain 8-Ⅲ.Furthermore,the optimal temperature and pH for the GOD produced by 8-Ⅲ-a44 strain were 15℃and 6.5,respectively.Besides,the enzyme was stable at 0-35?C,which indicated that it was a low-temperature enzyme.In addition,K^+and Ni^2+significantly promoted its activity.In conclusion,this study expands the source of GOD and lays a foundation for its applications in seafoods and feeds preservation.