Catalytic Properties of Amylolytic Enzymes Produced by Gongronella butleri Using Agroindustrial Residues on Solid-State Fermentation.

Amylases catalyze the hydrolysis of starch, a vegetable polysaccharide abundant in nature. These enzymes can be utilized in the production of syrups, alcohol, detergent, pharmaceutical products, and animal feed formulations. The aim of this study was to optimize the production of amylases by the filamentous fungus Gongronella butleri by solid-state fermentation and to evaluate the catalytic properties of the obtained enzymatic extract. The highest amylase production, 63.25 U g-1 (or 6.32 U mL-1), was obtained by culturing the fungus in wheat bran with 55% of initial moisture, cultivated for 96 h at 25°C. The enzyme presented optimum activity at pH 5.0 and 55°C. The amylase produced was stable in a wide pH range (3.5-9.5) and maintained its catalytic activity for 1 h at 40°C. Furthermore, the enzymatic extract hydrolyzed starches from different vegetable sources, presenting predominant dextrinizing activity for all substrates evaluated. However, the presence of glucose was observed in a higher concentration during hydrolysis of corn starch, indicating the synergistic action of endo- and exoamylases, which enables the application of this enzymatic extract to produce syrups from different starch sources.

Production of beta-glucosidase on solid-state fermentation by Lichtheimia ramosa in agroindustrial residues: characterization and catalytic properties of the enzymatic extract

Background β-Glucosidases catalyze the hydrolysis of cellobiose and cellodextrins, releasing glucose as the main product. This enzyme is used in the food, pharmaceutical, and biofuel industries. The aim of this work is to improve the β-glucosidase production by the fungus Lichtheimia ramosa by solid-state fermentation (SSF) using various agroindustrial residues and to evaluate the catalytic properties of this enzyme. Results A high production of β-glucosidase, about 274 U/g of dry substrate (or 27.4 U/mL), was obtained by cultivating the fungus on wheat bran with 65% of initial substrate moisture, at 96 h of incubation at 35°C. The enzymatic extract also exhibited carboxymethylcellulase (CMCase), xylanase, and β-xylosidase activities. The optimal activity of β-glucosidase was observed at pH 5.5 and 65°C and was stable over a pH range of 3.5-10.5. The enzyme maintained its activity (about 98% residual activity) after 1 h at 55°C. The enzyme was subject to reversible competitive inhibition with glucose and showed high catalytic activity in solutions containing up to 10% of ethanol. Conclusions β-Glucosidase characteristics associated with its ability to hydrolyze cellobiose, underscore the utility of this enzyme in diverse industrial processes.