Selection and Breeding of Trichoderma viride Strains with High Productivity on Cellulase by Compound Mutation

[Objective] The aim was to screen Trichoderma viride strain with high cellulase activity.[Method] With a T.viride strain as the original strain,the screened mutant with the highest enzyme activity in each mutation treatment was used as the original strain in the next mutation.After mutation by ultraviolet(UV),nitrosoguanidine(NTG),diethyl sulfate(DES),the number of colony was recorded,the lethality of the colony was calculated and its CMCase activity was determined.[Result]When the spores were treated by UV for 200 s,their lethality was close to 100%.The relative enzyme activity of mutant U1 was the highest,being 110.4% of that of the original strain F1.When treated by NTG for 50 min,the lethality of spores was close to 100%.The relative enzyme activity of mutant N4 was the highest,being 128.9% of that of the original strain F1.When treated by DES for 50 min,the lethality of spores was close to 100%.The relative enzyme activity of D8 mutant was the highest,being 140.6% of that of the original strain F1.[Conclusion]T.viride strain D8,a strain with high productivity on cellulase and stable characters was got,its relative activity of CMCase was 40.6% higher than that of the original strain F1.