title: Influence of carbon and nitrogen sources and temperature on hyperproduction of a thermotolerant beta-glucosidase from synthetic medium by Kluyveromyces marxianus.
abstract: The effect of carbon source and its concentration, inoculum size, yeast extract concentration, nitrogen source, pH of the fermentation medium, and fermentation temperature on beta-glucosidase production by Kluyveromyces marxianus in shake-flask culture was investigated. These were the independent variables that directly regulated the specific growth and beta-glucosidase production rate. The highest product yield, specific product yield, and productivity of beta-glucosidase occurred in the medium (pH 5.5) inoculated with 10% (v/v) inoculum of the culture. Cellobiose (20 g/L) significantly improved beta-glucosidase production measured as product yield (YP/S) and volumetric productivity (QP) followed by sucrose, lactose, and xylose. The highest levels of productivity (144 IU/[L.h]) of beta-glucosidase occurred on cellobiose in the presence of CSL at 35 degrees C and are significantly higher than the values reported by other researchers on almost all other organisms. The thermodynamics and kinetics of beta-glucosidase production and its deactivation are also reported. The enzyme was substantially stable at 60 degrees C and may find application in some industrial processes.
authors.affiliation: National Institute for Biotechnology and Genetic Engineering, PO Box 577, Faisalabad, Pakistan. mirajoka@nibge.org
authors.forename: M I
authors.initials: MI
authors.lastname: Rajoka
authors.forename: Samia
authors.initials: S
authors.lastname: Khan
authors.forename: Farooq
authors.initials: F
authors.lastname: Latif
authors.forename: Riaz
authors.initials: R
authors.lastname: Shahid
mesh_terms: D000818:Animals; D050260:Carbohydrate Metabolism; D002244:Carbon / Q000502:physiology*; D003470:Culture Media; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007716:Kluyveromyces / Q000201:enzymology*; D009584:Nitrogen / Q000502:physiology*; D013696:Temperature; D001617:beta-Glucosidase / Q000096:biosynthesis* / Q000494:pharmacology
chemical_list: D003470:Culture Media; D002244:Carbon; D001617:beta-Glucosidase; D009584:Nitrogen