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

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.