Effect of Media Composition and Growth Conditions on Production of beta-Glucosidase by Aspergillus niger C-6

摘要

The hydrolytic activity of fungal originated beta-glucosidase is exploited in several biotechnological processes to increase the rate and extent of saccha-rification of several cellulosic materials by hydrolyzing the cellobiose which inhibits cellulases.In a previous presentation,we reported the screening and liquid fermentation with Aspergillus niger,strain C-6 for beta-glucosidase production at shake flask cultures in a basal culture medium with mineral salts,corn syrup liquor,and different waste lignocellulosic materials as the sole carbon source obtaining the maximum enzymatic activity after 5-6 d of 8.5 lU/mL using native sugar cane bagasse.In this work we describe the evaluation of fermentation conditions:growth temperature,medium composition,and pH,also the agitation and aeration effects for beta-glucosidase production under submerged culture using a culture media with corn syrup liquor (CSL) and native sugar cane bagasse pith as the sole carbon source in a laboratory fermenter.The maximum enzyme titer of 7.2 lU/mL was obtained within 3 d of fermentation.This indicates that beta-glucosidase productivity by Aspergillus niger C-6 is function of culture conditions,principally temperature,pH,culture medium conditions,and the oxygen supply given in the bioreactor.Results obtained suggest that this strain is a potential microorganism that can reach a major level of enzyme production and also for enzyme characterization.