Optimization Of Cellulase Production By Penicillium ZH1 Fermentation And Study On Its Enzymatic Properties

Cellulose is the richest renewable resource in the world,cellulase produced by microbial can degrade cellulose into monosaccharides,then converts it into energy,food and chemicals.It is great significance to solve the problem of environmental pollution and shortage of resources.However,existing strains product cellulase which have low enzyme activity and the production cost is expensive.Therefore,the study of screening of highly degradable cellulose strains and some related content has become a hot topic at abroad.1.In this study,seven samples were harvested from the farmhouse in Jianping county.seven samples were collected from farmhouse in Jianping county,and 13 strains were obtained by isolation and purification,It was screened by four kinds of screening medium for cellulose,filter paper,microcrystalline cellulose and Congo red,and combined with cellulase activity determination,the strain E2 was obtained from the high-yield cellulase.The strain was identified as Penicillium ochrochloron by morphological identification and phylogenetic analysis.2.The optimum conditions for the liquid fermentation of Penicillium were as follows:the carbon source was straw,the carbon source concentration was 3%,the nitrogen source was peanut powder and KNO3,the nitrogen content concentration was 0.4%,the amount of CaCl2 added 0.05%,the initial pH was 3,the inoculation amount was 8%,the temperature was 30?,and the incubation time was 144h.Under this condition,finally,FPase was 28.58 U/mL,CMCase was 54.88U/mL,and ?-Gase was 194.16U/mL.3 The optimum conditions for the solid fermentation of Penicillium were as follows:the nitrogen source was peanut powder,the water content(solid:liquid)was 1:3,the inoculation amount was 5%(spore suspension 107/mL),The optimum initial pH was 4,the grain size was 40-60,the fermentation temperature was 30?,and the incubation time was 72 hours.Under this condition,finally,FPase was 148.29U/g,CMCase was 256.68U/g,and ?-Gase was 230.20U/g.4.The crude enzyme solution of the strain was precipitated by ammonium sulfate and Sephadex G-75 was utilized to obtain a group of endoglucanase,the molecular weight was 29.7 kDa.The study of the enzymatic properties of endoglucanase showed that:The optimum reaction temperature of the enzyme is 40?,and the thermal stability was 40?.Its optimum pH was 5.0,the optimum pH stability was 3.0 Metal ions K+ and Ca2+ have a promoting effect on endoglucanase,.Na+,Mn2+,Zn2+,Co2+ and Fe2+ had different inhibitory effects on endoglucanase,and Mn2+,Co2+ and Fe2+ had obvious inhibitory effect on endoglucanase.The substrate specificity for endoglucanase,which had enzymatic activity against MCC and filter paper,has no enzymatic activity against salicylol,chitin and pNPC.The Km of endoglucanase with sodium carboxymethyl cellulose was 18.45 mg/mL and Vmax was 18.18 mg/(mL· min).