Study On Cultural Condition Optimization Of Ganoderma Lucidum With High β-glucosidase Production,Its Enzymatic Characteristics

This paper aimes to ganoderma strains as the research object, the optimization of liquid fermentation conditions, improved the ability of producing β-glucosidase, provided further biotransformation of flavonoids by G. lucidum. Then the liquid fermentation of G. lucidum produced by β-glucosidase was purified, enzymatic properties of the enzyme, established the experimental for future industrial applications etc. The main conclusions are as follows:Optimization of the Medium Composition for Production of β-glucosidase by Ganoderma lucidum was studied in this article.Effect of the type and concentration of carbon and nitrogen source was investigated.The G. lucidum was screened in seven tested strains for the following experiment. The G. lucidum was identified as G. lucidum, which could be used in health food with edible safety.Base on the result,the response surface methodology was used to optimize the medium and the result listed as follows:malt extract 7.10%,bean pulp 1.62%,yeast extract 1.93%, KH2PO40.3%,MgSO40.15%,VB1 0.005%,pH 5.5 and fermented for 7 days at 28℃ with shaking at 180rpm, the production mycelia biomass and β-glucosidase could reach maximum. In this paper, the wort was prepared with European Brewery Cenvention method, and it is the first time to use wort into fermentation medium of G. lucidum for increasing the production of intracellular triterpenoids. Under these conditions mycelial biomass and β-glucosidase activities in the fermentation mycelia achieved at 3.5295U/mL,3.3266g/100mL,and increased by 187%,160% respectively compared with the basic medium,which laid the foundation for the further study of G. lucidum bioconversion.The crude enzyme solution was purified by ammonium sulfate precipitation, dialysis and S-100 Sphacry 1 molecular sieve chromatography in order to obtain the high purity of beta. Among them, ammonium sulfate two precipitation saturation of 30% and 70%, making the enzyme purity increased by 6.9; S-100 Sphacry1 chromatography purification of crude enzyme, enzyme purity increased by 20.4. The purified enzyme was identified by SDS-PAGE, to determine the molecular weight of 93.7 kDa, with molecular p-glucosidase range. Enzymatic analysis results show that the beta glucosidase enzyme optimum temperature is 60℃,40 to 60℃ save 60 min after still has good thermal stability; the optimum pH was 5.0, in acidic conditions,4.0-5.0 24h still has higher enzyme activity.