具有β-半乳糖苷酶转苷能力的菌株筛选及鉴定  

Screening and Identification of β-Galactosidase-Producing Microorganism with Transgalactosylation Activity

作　　者：钟义华[1] 唐蕾[1] 吴亢[1] 杨瑞金[2] 朱松[3] 

机构地区：[1]江南大学工业生物技术教育部重点实验室,江苏无锡214122 [2]江南大学食品学院,江苏无锡214122 [3]江南大学食品科学与技术国家重点实验室,江苏无锡214122

出　　处：《食品与生物技术学报》2008年第5期83-85,共3页Journal of Food Science and Biotechnology

基　　金：国家863计划项目(2006AA10Z336)

摘　　要：以乳糖为惟一碳源,5-溴-4-氯-3-吲哚--βD-半乳糖苷(X-gal)为显色剂,从土壤中筛选出10株产β-半乳糖苷酶较高、生长较好的菌株。在30℃下发酵产酶,测定邻硝基苯-β-D-半乳糖苷(ONPG)水解能力。在50 mmol/L磷酸钾缓冲液(pH 7.0)中,加入400 g/L乳糖和200 g/L果糖,并分别添加10株菌所产β-半乳糖苷酶,至酶活为400 U/L,37℃下反应8 h,经高效液相色谱分析,编号为2-1样品中含有乳果糖。通过形态特征和16S rDNA序列分析,鉴定菌株2-1为节杆菌属。Ten strains which produced β-galactosidase were screened from soil using lactose as sole carbon source and 5-bromo-4-chloro-3-indolyl-β-D galactopyranoside （X gal） as indicator. The hydrolysis activity of β-galactosidase was measured using o-nitrophenl-β-D-galactopyranoside （ONPG） as substrate. The transgalactosylation reaction was performed in 50 mmol/L phosphate buffer （pH 7.0） containing 400 g/L of lactose, 200 g/L of fructose and 400 U/L of β- galactosidase. The products were analyzed by high-performance liquid chromatography （HPLC） after 8 h at 37 ℃. The reaction mixture of strain 2-1 contained lactulose which suggested that the enzyme produced by this strain exhibited the transgalactosylation activity. The strain was further identified as Arthrobacter sp. through 16S rDNA sequence analysis and morphology observation.

关 键 词：Β-半乳糖苷酶 乳果糖 16SrDNA 

分 类 号：TS244[轻工技术与工程—制糖工程]