BREWERY-RESIDUE UTILIZATION OF A FRESHLY ISOLATED A. NIGER SP. UPT-03 FOR PROTEASE PRODUCTION UNDER SOLID-STATE FERMENTATION

Abstract

The operation parameters used in solid-state fermentation (SSF) support the growth of filamentous fungi, which grow on solid substrates producing important metabolites such as proteases. The aim of this work is to obtain fungal proteases by SSF using the residues of a local brewery industry (barley bagasse and trub), that have high contents of proteins and soluble matter such as carbohydrates, vitamins, and mineral salts. The methodology includes the preparation of the residues, the screening of microorganisms, evaluation of the operation conditions for SSF using factorial design, purification and partial characterization of the protease. The results indicate that A. niger sp. UPT-03 isolated from the residue shows higher yields in terms of enzyme production (0.36 U gdm^-1 h^-1). The purification with DEAE-cellulose resulted in protease recovery with 30-fold of purification with a specific activity of 550 U mg protein^-1. Higher proteolytic activity of purified enzyme was obtained at pH 5.5 and 55 ºC.