Influence of Carbon and Nitrogen Sources and Temperature on Hyperproduction of a Thermotolerant p-Glucosidase From Synthetic Medium by Kluyveromyces marxianus

摘要

The effect of carbon source and its concentration,inoculum size,yeast extract concentration,nitrogen source,pH of the fermentation medium,and fermentation temperature on p-glucosidase production by Kluyveromyces marxianus in shake-flask culture was investigated.These were the independent variables that directly regulated the specific growth and P-glucosidase production rate.The highest product yield,specific product yield,and productivity of p-glucosidase occurred in the medium(pH 5.5)inoculated with 10%(v/v)inoculum of the culture.Cellobiose(20 g/L)significantly improved p-glucosidase production measured as product yield(Y_p/s)and volumetric productivity(Q_P)followed by sucrose,lactose,and xylose.The highest levels of productivity(144 IU/[L centre dot h])of P-glucosidase occurred on cellobiose in the presence of CSL at 35 deg C and are significantly higher than the values reported by other researchers on almost all other organisms.The thermodynamics and kinetics of P-glucosidase production and its deac-tivation are also reported.The enzyme was substantially stable at 60 deg C and may find application in some industrial processes.