产β-葡萄糖苷酶酿酒酵母菌株紫外诱变选育及酶学性质分析

UV mutation of production Saccharomyces cerevisiae strain of β-glucosidase and its enzyme characteristics

摘要: 为了得到高产胞外β-葡萄糖苷酶的酿酒酵母（Saccharomycaes cerevisiae）菌株,采用紫外线诱变技术对菌株MQFSM-3进行处理,研究了紫外诱变条件对菌株致死率的影响,并对突变菌株酶活及酶学性质进行评价。结果表明,出发菌株在辐照剂量为3500μJ/cm2的紫外灯下照射9 min,致死率为81.09%;通过初筛、复筛及多次传代培养,突变菌株UV-45产酶稳定,酶活提高41.64%,该酶最适温度为50℃,在20⁵0℃热稳定性良好;最适p H为5.5,在p H4.0⁶.5酶活力相对稳定。

Abstract: In order to screen a high extracellular β-glucosidase producing mutant strain of Saccharomycaes cerevisiae, the method of UV mutation was used on wild yeast of MQFSM- 3. Death rate affected by UV mutagenesis conditions were determined,enzyme activity and enzymatic characteristics of mutant strain were also evaluated. The results showed that the dose of 3500 μJ/cm2,irradiation 9 min,mortality reached 81.09%.By preliminary screening,rescreening and subculturing for many times,a stable enzyme production of mutant UV- 45 was obtained. Compared with the original strain, its enzyme activity was improved 41. 64 %. The enzymatic characteristics were analyzed that the optimum temperature of UV-45 was 50 ℃,and it had a good thermal stability between 20⁵0 ℃. The optimum p H was 5.5,and between p H4.0 to 6.5,the enzyme activity was relatively stable.