产β-葡萄糖苷酶酿酒酵母菌株的化学诱变选育及产酶条件优化

Chemical mutation of strain and optimization of production β- Glucosidase from Saccharomyces cerevisiae

以实验室保存的一株酿酒酵母菌株UV-45为出发菌株,通过硫酸二乙酯(DES)诱变筛选及致死率测定,得到一株产β-葡萄糖苷酶稳定,酶活为74.26 U/m L的突变菌株UV-E-16,与出发菌株相比,其酶活提高了22.74%;通过Plackett-Burman方法对该菌株发酵产酶的相关因素进行分析,得出初始p H、培养温度和接种量为显著影响因子;利用Box-Behnken实验设计和响应曲面法获得其最佳产酶条件为初始p H5.62、培养温度29.5℃、接种量6.12%,该条件下,菌株UV-E-16产β-葡萄糖苷酶酶活为90.91 U/m L。经化学诱变及响应面优化产酶条件,出发菌株UV-45产β-葡萄糖苷酶酶活力提高了50.24%,具有工业化应用的潜力。

By the screening of diethyl sulfate（ DES） mutation and death rate determination,a mutant strain UV-E-16,which characterized by stable β- glucosidase producing capability and enzyme activity of 74.26 U / m L,was obtained from a laboratory saved Saccharomyces cerevisiae UV- 45.Compared with the original strain,enzyme activity of UV- E- 16 was improved by 22.74%.Initial p H,temperature,and inoculation dose were selected as the significant impact factors affecting on enzyme production according to Plackett- Burman design.Further optimizing was conducted by Box- Behnken design and response surface methodology.Related results showed that the optimized conditions were initial fermentation p H of 5.62,culture temperature of 29.5 ℃ and inoculum 6.12%,and the β- glucosidase producing activity of UV- E- 16 was 90.91 U / m L under the conditions.The activity ofβ- Glucosidase synthesis was improved by 50.24% in comparison with UV- 45,UV- E- 16 can be regarded as a promising strain with industrial application properties.