Amino Acid Supplementation Improves the Production of Extracellular Peptidases by Aspergillus Section Flavi and their Ionic Immobilization

Abstract Bioprocess studies have been highlighted due to the importance of physiological processes and industrial applications of enzymes. The potential of peptidase production from Aspergillus section Flavi using different amino acids as a supplemental nitrogen source was investigated. A production profile revealed that amino acids had positive effects on peptidase production when compared to the control without amino acids. Optimal production (100 U/mL) was obtained with Arginine amino acid in 96 h of fermentation. Extracellular peptidase from Aspergillus section Flavi was identified in submerged bioprocesses by in situ activity. Biochemical studies revealed that the maximum activities of the enzyme extract were obtained at pH 6.5 and a temperature of 55°C. The inhibition by EDTA and PMSF suggests the presence of more than one peptidase while the Ni2+ and Cu2+ had a negative influence on the enzyme activity. When the crude extract was reversibly immobilized on ionic supports, DEAE-Agarose and MANAE-Agarose the derivative showed different profiles of thermal and pH stabilities. Hence, this study revealed the basic properties and biochemical characteristics that allowed the production improvement of this class of enzyme. Moreover, with known properties stabilization and immobilization process is required to further explore its biotechnological capacities.

Surface response methodology for the optimization of lipase production under submerged fermentation by filamentous fungi

Abstract A Plackett–Burman Factorial Design of 16 experiments was conducted to assess the influence of nine factors on the production of lipases by filamentous fungi. The factors investigated were bran type (used as the main carbon source), nitrogen source, nitrogen source concentration, inducer, inducer concentration, fungal strain (Aspergillus niger or Aspergillus flavus were selected as good lipase producers via submerged fermentation), pH and agitation. The concentration of the yeast extract and soybean oil and the pH had a significant effect (p < 0.05) on lipase production and were consecutively studied through a Full Factorial Design 23, with the concentration of yeast extract and pH being significant (p < 0.05). These variables were optimized using a central composite design, obtaining maximum lipolytic activities with the use of 45 g/L of yeast extract and pH 7.15. The statistical model showed a 94.12% correlation with the experimental data.