中性乳糖酶高产菌的选育

Screening of High-Yielding Strains for Neutral Lactase

本文对产中性乳糖的乳酸酵母２１２７菌（９．３２ｕ／ｍｌ）采用紫外线、亚硝基胍等诱变因子进行诱变处理，从突变菌株中筛选获得一株高产菌２１２７－ＵＮ，其活力为１７．１２ｕ／ｍｌ．比２１２７菌活力提高了１．８倍。对２１２７－ＵＮ的发酵培养基及发酵工艺条件进行了试验，确定了优化发酵培养基中的碳源、有机及无机氮源、微量元素的组成及波度。优化后的培养条件为：ｐＨ７．０，２５０ｍｌ三角瓶中装液量为３０ｍｌ，温度３０℃，时间７２ｈ。优后２１２７－ＵＮ菌株活力为２４．６３ｕ／ｍｌ，比未优化前提高了４０％。

Induction used UN , NTG was carried out on Sacch. lactis 2127 (9. 32u/ml ). A high-yieldingmutant, 2127 - UN, was obtained. It's productivity increased to 17. 12u/ml, about 1. 8 times comparedto the starting strain 2127.The fermentation medium and conditions for the mutant2127 - UN ware investigated. The formulaof culture medium was optimized, including carbon source , organic and inorganic nitrogen sources andtrace elements. The optimum conditions were: PH: 7. 0, capacity: 30ml/triangular bottle (250ml ).temperature: 30℃, time: 72h. Thereby, the productivity of 2127 - UN reached 24. 63u/ml, increasing40%.