Characterization of β-glucosidase produced by the white rot fungus Flammulina velutipes

• Published in: Journal of microbiology and biotechnology Vol. 25; no. 1; pp. 57 - 65
• Main Authors: Mallerman, Julieta, Papinutti, Leandro, Levin, Laura
• Format: Journal Article
• Language: English
• Published: Korea (South) 한국미생물·생명공학회 01.01.2015
• Subjects: beta-Glucosidase - antagonists & inhibitors; beta-Glucosidase - chemistry; beta-Glucosidase - metabolism; Cellobiose - metabolism; Culture Media; Enzyme Stability; Ethanol - metabolism; Fermentation; Flammulina - enzymology; Glucose - metabolism; Glucosides; Hydrogen-Ion Concentration; Kinetics; Molecular Weight; Substrate Specificity; Temperature; 생물학
• ISSN: 1017-7825; 1738-8872
• DOI: 10.4014/jmb.1401.01045

β-Glucosidase production by the white rot fungus Flammulina velutipes CFK 3111 was evaluated using different carbon and nitrogen sources under submerged fermentation. Maximal extracellular enzyme production was 1.6 U/ml, corresponding to a culture grown in sucrose 40 g/l and asparagine 10 g/l. High production yield was also obtained with glucose 10 g/l and asparagine 4 g/l medium (0.5 U/ml). Parameters affecting the enzyme activity were studied using p-nitrophenyl-β-D-glucopyranoside as the substrate. Optimal activity was found at 50°C and pHs 5.0 to 6.0. Under these conditions, β-glucosidase retained 25% of its initial activity after 12 h of incubation and exhibited a half-life of 5 h. The addition of MgCl2, urea, and ethanol enhanced the β-glucosidase activity up to 47%, whereas FeCl2, CuSO4, Cd(NO3)2, and cetyltrimethylammonium bromide inflicted a strong inhibitory effect. Glucose and cellobiose also showed an inhibitory effect on the β-glucosidase activity in a concentration-dependent manner. The enzyme had an estimated molecular mass of 75 kDa. To the best of our knowledge, F. velutipes CFK 3111 β-glucosidase production is amongst the highest reported to date, in a basidiomycetous fungus.