摘要
通过对９０４３Ｃ１２菌株培养条件的研究，使其产脲酶活力达２．４Ｕ／ｍＬ，较原活性０．３４Ｕ／ｍＬ提高７．１倍．对该酶的酶学特性进行初步研究表明，尿素对该菌脲酶的生物合成具有显著促进作用，其最适ｐＨ为５．０，最适温度为４２℃；但在含２０％（ｖ／ｖ）乙醇下最适ｐＨ为４．５，最适温度为４６℃，３５℃以下较稳定，酶经６５℃１５ｍｉｎ巴氏消毒完全失活．模拟试验结果表明，２５℃ｐＨ５．０条件下，在含乙醇１６％或２０％（ｖ／ｖ）、尿素３０ｍｇ／Ｌ的模拟酒中，添加１０Ｕ／Ｌ脲酶，可使尿素去除率在３６ｈ内达９０％以上．
The influence of culture conditions on urease produced by strain 9043 C 12 was investigated.The Urease producing activity of the strain in simple medium reaches 2.4 U/ml.Urea had a markedly stimulatous effect on the biosynthesis of urease.The optimum pH and temperature was 5.0 and 42 ℃ for activity of urease from strain 9043 C 12 ,but the maximum activity of this urease appeared under optimum pH 4.5,optimum temperture 46 ℃ and 20% (v/v) ethanol solution,and was stable at lower 35 ℃ but was completely inactivited after Pasteur sterilization with 65 ℃ for 15 min.The urea decomposition rate was more than 90% in stimulated rice wine with 16% or 20%(v/v) ethanol and 30 mg/L of urea within 36 hrs after addition of 10 U/L partially purified urease at 25 ℃ and pH 5.0.
基金
浙江省自然科学基金
关键词
脲酶
尿素
尿素去除率
黄酒
urease
urea
simulated rice wine
urea decomposition rate
