Mutation Breeding Of Cellulase-producing Fungi And Optimization Of It's Fermentation Conditons

Cellulose is the most abundant organic raw material in the world,and it is the only renewable resource that is available in large quantities.Presently,only a few cellulose are utilized,most of cellulose arc wasted and pollute environment.So it has great realistic meaning for human being to solve environment pollution,food shortage and energy crisis that using cellulase produced by microorganism transform cellulose to energy,chemical material and food.Because the capability of producing cellulase is low and the composition of eellulase is imbalance,so the cellulase did not achieve cosmically industrial production and application.Be dead against of these questions in production cellulase of the strain that is capable of producing,many people make great efforts to resolve it,including mutation breeding,optimize fermentation conditions,gene clone,and so on.But China did not make a breakthrough at all time.Most factory adopted solid fermentation,liquid fermentation only at the laboratory level in china.Trichoderma Koningii C-3 conserved by our lab used as fermentation strain.The characteristic configuration and dynamic trend of cellulase secreting from Trichoderma Koningii MW₁₆ was studied.It was also studied that the infection of different nutriment and growth condition on strain producing cellulase.On the foundation of optimizing culture medium and researching various factors on Trichoderma Koningii MW₁₆ producing cellulase,fermentation condition for producing cellulase by mutation strain was primarily ascertained.The main experimental results were summarized as folIowings. A mutated strain MW₁₆ was obtained through treatment by EMS based on the Trichoderma Koningii C-3.The relation about mutation time and positive mutation rate of EMS were studied.The result shoud that the optimum mutation time of Trichoderma Koningii C-3 induced by EMS is 100s. Primary screening was according to the bigger transparent circle using plate method.Secondary screening was according to shaking flask fermentation, the test of filter paper enzyme activity(FPase),CMC-enzyme activity(CMCase),β-glucosidase activity and CBH-enzyme activity through liquid fermentation.The enzyme activity of the strain MW₁₆ was higher than C-3.After continuative culture for 10 generations, the producing cellulase capability of MW₁₆ was stable. The conditions of solid fermentation and liquid fermentation were studied respectively,the optimum conditions of solid fermentation is that optimum ratio corn straw and wheat bran equal 60:20, optimum ratio substrate and water equal 1:1,optimum pH values is 6.0. The optimum conditions of liquid fermentation is that nitrogen fountainhead is 0.5% proteose peptone, optimum pH values is 7.0,optimum inoculation amount was 6%, optimum fermentation temperature is 30℃, optimum time is 120h.