Title
Production and characterization of cellulases from Aspergillus niger under static fermentation
Authors
NAILA FATIMA, IRFAN AHMAD, HAFIZ ABDULLAH SHAKIR, MUHAMMAD KHAN, MARCELO FRANCO and MUHAMMAD IRFAN

Received March 11, 2024
Published Volume 58 Issue 7-8 July-August
Keywords Aspergillus niger, cellulase, characterization, CMCase, FPase

Abstract
The ever-increasing uses of cellulase in various industries have made it popular among researchers. Annually, a large amount of fruit wastes go into vain, which is a great source of cellulases. The objective of this study is to use grape wastes as substrate for production of cellulases from Aspergillus niger using static fermentation. CMCase and FPase assays were performed to characterize the cellulases. The cellulases’ CMCase and FPase activities and stabilities were analyzed for optimum temperature and pH. The effect of substrate concentration and kinetic constants Km and Vmax, along with thermodynamic analysis, were determined. The effects of several metals on the activity of the enzyme were observed. The optimal temperatures were found as 40 °C and 50 °C for CMCase and FPase activity, respectively. CMCase activity shows stability at 20 °C-60 °C, FPase shows low thermal stability as its activity starts to decrease after 50 °C. CMCase and FPase both show maximum activity at pH 6, and maintain their stability at pH 6-7. The values of Km and Vmax obtained from Lineweaver and Burk plot for CMCase are 0.648 mM and 12.953 mM/min, and for FPase are 0.975 mM and 41.493 mM/min. The Arrhenius plot was used to calculate activation energy (Ea) as -19 kJ/mol, and enthalpy of reaction (ΔH) as 16.4 kJ/mol, while entropy ΔS -16.4 kJ/mol was obtained from the plot of ln(Vmax/T) versus the inverse of temperature (1/T). Most metals induce enzyme activities, whereas EDTA inhibits enzyme activities. The findings suggest A. niger has remarkable cellulase production potential from grape wastes in static fermentation, at optimum temperature and pH levels for achieving enzyme activity and stability.