在低乳糖牛奶加工过程中需要高活性的低温乳糖酶作为添加剂.为此,从采集土样中分离纯化获得1株低乳糖奶加工过程中需要的高乳糖酶活性候选菌株,应用形态学和分子生物学方法,初步鉴定该菌株为动球菌属(Planococcus sp.),命名为Planococcussp.Y.研究表明,该菌株是1株低温菌株,其最适生长温度为25℃,最佳生长pH值为7.0,所产酶为胞内酶,粗酶液的最适酸碱度和温度分别为pH7.0和25℃.%High activity of cold-adapted low lactase as an additive is necessary in processing low lactose milk. The psychrotrophic and bacterium strain was isolated from surficial soils. A strain capable of producing psychrotrophic a lactase was identified as a Planococcus sp. Y according to the morphological and molecular characteristics. The optimal conditions for the growth of the strain were examined. The optimal temperature and pH value for growth were 25℃ and 7.0,respectively. Study on the activity of the lactase showed that the optimal temperature and pH for the activity of the crude enzyme was 25℃ and 7.0,respectively. The lactase from Planococcus sp. Y was located intracellularly. This will provide a foundation for producing low lactose milk in future.
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