摘要
酶法合成乳果糖需要使用同时具备水解和转苷活力的β-半乳糖苷酶为催化剂。采用物理诱变,培养基优化手段,以提高细菌产该类β-半乳糖苷酶的能力为目的,自然筛选获得的具有转苷能力的节杆菌Arthrobacter sp.,经紫外线照射处理,采用5-溴-4-氯-3-吲哚-β-D-半乳糖苷(X-gal)为平板筛选显色剂,加之摇瓶发酵筛选,得到8株产酶水平明显提高的诱变株,其中Arthrobacter sp.M2酶活力较野生株提高了89%,传代5次酶活基本稳定。采用正交实验优化产酶培养基,结果表明:在乳糖浓度为10g/L,玉米浆浓度为22g/L,Fe3+浓度为1.5mmol/L时效果最佳,酶活水平进一步提高了113%。紫外诱变和培养基优化有效地提高了节杆菌产β-半乳糖苷酶的水平。
The enzymatic synthesis of lactulose needs the β- galactosidase with both hydolysis and transgalactosylation activities as catalyst.Improving the productivity of such kind of enzyme is necessary.Naturally isolated Arthrobacter sp. was mutated with ultraviolent radiation. The mutants with higher β- galactosidase productivities were obtained by the screening on the selective medium with 5-bromo-4-chloro-3-indolyl-15-D- gatactopyranoside（X-gal） as indicator and then by the liquid fermentation.The productivity of the best mutant Arthrobacter sp.M2 was 89% higher than the wild type.The optimum medium for the β-galactosidase production determined through orthogonal test was lactose 10g/L, corn syrup 22g/L, Fe3＋ 1.5mmol/L.The productivity was futher increased 113% using the optimized medium.Ultraviolet mutagenesis combined with medium optimization improved the productivity of β-galactosidase from Arthrobacter effectively.
出处
《食品工业科技》
CAS
CSCD
北大核心
2011年第7期192-194,共3页
Science and Technology of Food Industry
基金
国家863探索项目(2006AA10Z336)
关键词
节杆菌
紫外诱变
Β-半乳糖苷酶
Arthrobacter sp.
ultraviolet mutagenesis
β- galactosidase
