Cellulase production by Aspergillus unguis in solid state fermentation

Abstract

Lignocellulosic substrates are a good carbon source and provide rich growth media for a variety of microorganisms which produce industrially important enzymes. Cellulases are a group of hydrolytic enzymes such as filter paperase (FPase), carboxymethyl cellulase (CMCase) and β-glucosidase—responsible for release of sugars in the bioconversion of the lignocellulosic biomass into a variety of value-added products. This study examined cellulase production by a newly isolated Aspergillus unguis on individual lignocellulosic substrates in solid state fermentation (SSF). The maximum peak production of enzymes varied from one substrate to another, however, based on the next best solid support and local availability of groundnut fodder supported maximum enzyme yields compared with other solid supports used in this study. Groundnut fodder supported significant production of FPase (5.9 FPU/g of substrate), CMCase (1.1 U/g of substrate) and β-glucosidase activity (6.5 U/g of substrate) in SSF. Considerable secretion of protein (27.0 mg/g of substrate) on groundnut fodder was recorded. Constant increment of protein content in groundnut fodder due to cultivation of A. unguis is an interesting observation and it has implications for the improvement of nutritive value of groundnut fodder for cattle.