Production of intracellular β-xylosidase from the submerged fermentation of citrus wastes by Penicillium janthinellum MTCC 10889

Production of intracellular beta-xylosidase was studied in cultures of Penicillium janthinellum grown on citrus fruit waste supplemented cultivation media. Both dried orange peel and sweet lime peel could induce the production of this enzyme. The working strain showed a pronounced optimum pH and temperature for beta-xylosidase production at 6.0 and 27 degrees C, respectively. The enzyme production was found to remain stable for a long period of 120 h. Orange peel and sweet lime peel showed different responses in the presence of various nitrogen sources, probably due to their differences in hemicellulosic contents. This could be further confirmed by the difference in enzyme production after pretreatment with acid and alkali.