Scaling up the optimized production of Aspergillus heteromorphus URM0269 collagenase in soybean agroindustrial residue.

Abstract

Collagenase and protease productions from Aspergillus heteromorphus URM0269 were optimized by submerged fermentation using soybean flour as substrate. Fermentations were performed according to composite design using the concentrations of substrate and yeast extract as the independent variables. The best condition was scaled up in a stirred tank bioreactor to assess the fermentation kinetics. The highest production of both enzymes occurred at concentrations of 2.0 % substrate and 0.1 % yeast extract. Contrariwise, after scale-up, collagenase activity increased from 33.5 to 148.5 U/mL, while the protease decreased from 16.3 to 11.7 U/mL. A. heteromorphus URM0269 showed a maximum growth rate of 0.09 h^-1 and yields of protease and collagenase on biomass, after 65 h of 2.70 and 34.22 U/mgx, respectively. Collagenase acted optimally at 40 °C and pH 6.0 on collagen as a substrate and displayed an allosteric trend, achieving a maximum reaction rate of 132.47 U/mL. Thermodynamic parameters of collagen degradation such as Gibbs free energy (74.16 kJ/mol), enthalpy (11.64 kJ/mol), entropy (-199.63 J/K.mol), and activation energy (14.25 kJ/mol) were determined for optimal temperature. These results demonstrated that soybean flour is a potential agroindustrial residue for collagenase production. Furthermore, the collagenase displayed promising biochemical and thermodynamic features for other biotechnological applications.