摘要
探讨藏灵菇马克斯克鲁维酵母K1菌株胆盐水解酶作用底物的反应条件与不同化学试剂对酶活性的影响及其发酵动力学类型。采用单因素多水平试验方法,在pH值4～8、温度31℃～43℃、底物浓度4mmol/L～8mmol/L及不同化学试剂(SDS、EDTA、尿素、Cu2+、Mg2+、Ca2+、Fe3+、Al3+、Mn2+)的条件下,胆盐水解酶与底物反应30min,检测酶活力;平板活菌计数法分析细胞生长与产酶的关系;双倒数作图法求得酶促反应动力学常数Km。结果表明,胆盐水解酶最适反应条件为:pH值为6.0、底物浓度7mmol/L、温度37℃,Fe3+、Ca2+、Mn2+及尿素对酶活性有较大提高作用,Mg2+、Al3+及SDS对酶的激活作用次之,Cu2+及EDTA对酶活性影响不大。K1菌株在18h～21h进入稳定期,于21h对数生长期的末期时酶活性达到最高,表明其胆盐水解酶发酵动力学类型为生长偶联合成型。其酶促反应动力学常数Km为2.10mmol/L,说明该酶与最适底物的亲和力较大。
The reaction condition of bile salt hydrolase from Kluyveromyces marxianus K1, the effect of different chemical reagents on the enzyme activity and the type of fermentation kinetics were investigated in this paper. The single factor and multi levels orthogonal experiments were applied. Enzyme activity was tested under the following conditions： pH value 4-8, temperature 31℃--43℃, concentration of substrate 4mmol/L-8mmol/L, different chemical reagents（SDS, EDTA, carbamide, Cu2＋, Mg2＋, Ca2＋, Fe3＋, Al3＋, Mn2＋） and reaction time 30 min. The relationship between cell growth and enzyme was analyzed by plate count method. The enzyme kinetics constant Km was calculated by double-reciprocal plot. The optimal reaction condition of bile salt hydrolase were as followed： pH value 6.0, concentration of substrate 7mmol/L, temperature 37℃. Fe3＋, Ca2＋, Mn2＋ and carbamide had significant effect on the enzyme activity, and Mg2＋, Al3＋, SDS had effects on the enzyme activation, and Cu2＋, EDTA had little effects on the enzyme activity. Strain K1 entered the stationary phases after 18 h-21 h. The enzyme activity reached the maximum value at late logarithmic phase after 21h. The experiments results showed the fermentation kinetics was growth couple. The kinetic constant Km of bile salt hydrolase was 2.10mmol/L. This indicated that there was a high affmity between bile salt hydrolase and optimimal substrate.
出处
《中国酿造》
CAS
北大核心
2010年第11期69-73,共5页
China Brewing
关键词
藏灵菇
马克斯克鲁维酵母K1
胆盐水解酶
特性
Tibetan kefir
Kluyveromyces marxianus K1
bile salt hydrolase
characteristics
