Production, Characterization, Kinetics, and Thermodynamics Analysis of Amyloglucosidase from Fungal Consortium

The current study aimed to produce an amyloglucosidase enzyme from the fungal consortium. The best amylolytic fungal consortia were identified as Alternaria alternata and Aspergillus niger through the 18S rDNA technique. Fermentation kinetics and various nutritional and cultural parameters were analyzed. Maximum production was obtained in M4 media, pH 5.5, 30 °C, and 4 mL inoculum at 150 rpm after 72 h of incubation. Along with that, sodium nitrate at 2.5%, maltose, beef extract 1%, zinc sulfate (0.1%), and Tween 80 (0.1%) supported the maximum amyloglucosidase production. Amyloglucosidase was partially purified up to 1.6 purification fold with a specific activity of 1.84 Umg⁻¹ in a stepwise manner by ammonium sulfate purification, dialysis, and ion exchange chromatography. The AMG enzyme also revealed maximum activity at 50 °C with 5.0 pH. Upon the kinetic analysis, the specific yield coefficient Yp/x and volumetric rates Qp and Qx were also found to be significant in the above optimized conditions. The Km value 0.33 mg mL⁻¹ and Vmax 26.31 U mL⁻¹ were obtained at 1% soluble starch substrate. Thermodynamic parameters for soluble starch hydrolysis were as follows: ΔH = 48.78 kJ mol⁻¹, (Ea) =  − 46.0 kJ mol⁻¹, and ΔS =  − 43.10 J mol⁻¹ K⁻¹. This finding indicates the indigenously isolated fungal consortium can be the best candidate for industrial applications.