产葡聚糖乳酸菌的筛选诱变及培养基的优化  

Screening, mutation breeding and medium optimization of glucan-producing lactic acid bacteria

作　　者：刘欢[1] 崔鑫[1] 孟祥晨[1] 

机构地区：[1]东北农业大学食品学院乳品科学教育部重点实验室,哈尔滨150030

出　　处：《食品科技》2015年第5期2-9,共8页Food Science and Technology

基　　金：教育部重点科技研究项目(20122325110017);教育部创新团队项目(IRT0959)

摘　　要：从市售及实验室发酵的泡菜中分离筛选产葡聚糖的乳酸菌,获得一株葡聚糖产量为(5.24±0.14)g/L的菌株2-17,经生理生化以及16S r DNA序列同源性分析,鉴定该菌株为肠膜明串珠菌肠膜亚种。通过亚硝基胍和紫外复合诱变改善该菌株的葡聚糖产量,确定最佳复合诱变条件为:菌株在MRS培养基中培养9 h,经浓度为0.5 mg/m L亚硝基胍处理80 min,置于30 W紫外灯45 cm处照射30 s。经2轮复合诱变后,得到一突变菌株UN2-18,葡聚糖产量为(7.54±0.08)g/L,较出发菌株提高了43.89%。该突变株连续传10代后,葡聚糖产量仍维持在7.5 g/L。通过单因素试验,确定最优廉价培养基为2%豆粕(水解度10%)、10%蔗糖、2%K2HPO4,在此条件下葡聚糖产量为(34.4±0.07)g/L,较优化前提高了3.56倍。One lactic acid bacteria strain 2-17 with the glucan-producing capacity of（5.24±0.14） g/L was isolated from the commercial pickles and the pickles made in the laboratory. This strain was identifi ed as Leuconostoc mesenteroides subsp. mesenteroides by a series of physiological and biochemical tests and analysing the 16 SrDNA sequence. The glucan-producing capacity of the strain was improved by exposing the strain to nitrosoguanidine and UV irradiation successively, and the optimal mutagenic condition was determined as the following： the strain was first cultured in the MRS medium for 9h and then was exposed to 0.5 mg/m L nitrosoguanidine for 80 minutes followed by exposure to UV radiation（30 W） from distance of 45.0 cm for 30 s; then the culture was treated by the same nitrosoguanidine-UV complex mutation again. After that, one mutant UN2-18 with the glucan-producing capacity of（7.54±0.08） g/L was obtained and the glucan production of this mutant was 43.89% higher than that of its original strain. In addition, the strain obtained by continuous subculturing the mutant UN2-18 for 10 generations leveled out its glucan production by around 7.5 g/L. The optimal culture conditions of the cheap medium were determined for 2% soybean meal hydrolysised with degree of 10%, 10% sucrose and 2% K2HPO4. The glucan production of UN2-18 was（34.4±0.07） g/L, improving by 3.56 fold.

关 键 词：乳酸菌 葡聚糖 诱变 豆粕 

分 类 号：TS201.3[轻工技术与工程—食品科学]