Study On The Pilot-Scale Production And Preparation Of Chymosin By Mucor MJ229

Chymosin is a key enzyme in cheese production.The aim of this research is to study pilot-scale production based on the early trials. The medium pilot-scale production was optimized, the best carrier of solid-state fermentation medium and the the main parameters of solid-state fermentation process were studied, pilot-scale production conditions of Mucor MJ229by solid state fermentation for producing chymosin were formulated.At the same time chymosin spray drying condition was optimized using single factor and response surface methodology and chymosin was preparation.The conclusions were as follows:According to the industrial production, the solid-state fermentation medium of MJ229were optimized by tray(25cm×25cm×4cm), the result showed that, the ratio of rice and wheat bran was0.3:0.7(w/w), polysorbate80was4%, Liquid-solid ratio was1:1.Curved plate (40cm x60cm x10cm) was used to optimize the best carrier of solid-state fermentation medium, the result showed the3kg/disk was best.The natural state and control of moisture and temperature conditions for solid state fermentation were studied, after72h fermented the results show that the activity in the regulating state fermentation was32.6%higher than the state of nature.Pilot-scale production conditions of Mucor MJ229was carried,2tons per batch. The changes of pH value and biomass in the solid-state fermentation process was studied.the results showed that in the fermentation process,pH values varied between5.8and6.3, in the pH range the Mucor suitable for the growth, the maximum biomass was in72h, the content was0.091g/dry matrix. After fermentation, the activity was up to6438U/g.Using single factor and response surface method for chymosin spray drying process conditions were optimized, effects of inlet temperature, addictive content, material flow and hot air flow on chymosin activity, the optimum spray condition:the inlet temperature was170℃, addictive was15%, material flow rate65mL/h, hot air flow54m3/h, the highest yield of the enzyme activity could achieve66.7±1.7%, the activity was up to123158+50U/g.Detected physicochemical and microbial index of chymosin, it is consistent with the provisions of the state; the chymosin was stored in4℃and25℃for stability studies, the results showed that4℃was better.