Screening of bacillus producing β-galactosidase and optimization of its enzyme production conditions | 产β-半乳糖苷酶芽孢杆菌的筛选及产酶条件的优化_

中国人. ［目的］ 筛选产β-半乳糖苷酶的芽孢杆菌并对其产酶条件进行优化。［方法］ 从土壤中筛选出一株具有β-半乳糖苷酶活性的菌株，对其进行鉴定并对其发酵产酶条件进行优化。［结果］ 该菌株被初步鉴定为巨大芽孢杆菌。该菌株的最佳碳源是乳糖，最佳氮源是牛肉膏和蛋白胨，Na+对产酶有明显的促进作用。当乳糖含量为1.20%，牛肉膏含量为0.63%，蛋白胨含量为1.04%时，该菌株所产β-半乳糖苷酶酶活可达3.68 U/ml。初始pH值为8.0，培养温度为45 ℃，接种量为2%，振荡培养17 h，该菌株所产β-半乳糖苷酶的酶活最高，为5.49 U/ml。［结论］ 该菌株在高温条件下生长旺盛，适宜生长pH值范围广，在生产实践中具有一定的应用价值。_

英语. ［Objective］The aim was to screen the bacillus producing β-galactosidase and optimize its conditions for enzyme production. ［Method］ A strain with β-galactosidase activity was screened from the soil. The strain was identified and its conditions for enzyme production was optimized. ［Result］ The strain was identified preliminarily as Bacillus megaterium. The optimum carbon source of the strain was lactose and optimum nitrogen sources were beef extract and peptone. Na+ had obvious promotion for its enzyme production. When the lactose content was 1.20% and beef extract content was 0.63% and when the peptone content was 1.04%，the enzyme activity of the strain producing β-galactosidase could be reached to 3.68 U/ml. When the initial pH value was 8.0，the culture temperature was 45 ℃，the inoculation amount was 2% and the shaking culture time was 17 h, the activity of β-galactosidase produced by the strain was highest， being 5.49 U/ml. ［Conclusion］ The strain grew vigorous under the high temperature and its pH range suitable for growing was wide，which had certain application value in practice.