Kinetic model supported improved and optimized submerged production strategy of cellulase enzyme from newspaper waste biomass

A systematic evaluation of microorganism’s potential towards biosynthesis of cellulases from inexpensive lignocellulosic feedstock through appropriate kinetic modelling facilitates understanding, optimization and designing of an effective industrial cellulase enzyme production process. The present study aims to optimize a submerged fungal cultivation strategy for cellulase production from abundantly available newspaper wastes (NPW). A combined pretreatment strategy consisting diluted, 1% (v v⁻¹) H₂SO₄ followed by 2% (wv⁻¹) NaOH treatment was highly effective to convert newspaper waste to an effective cellulose-enriched inducer for the production of cellulase. In addition, the composition of the most influential nutrient components like peptone and lactose was optimized with the help of response surface methodology for enhanced cellulase production with maximum activity levels. Maximum cellulase production of 8.64 g L⁻¹ with 7.82 FPU mL⁻¹ total activity levels was achieved from optimized composition of pretreated NPW 3.29% (w v⁻¹), lactose 2.94% (w v⁻¹) and peptone 1.53% (w v⁻¹). To analyse intrinsic inhibition effect of the substrate concentration on cellulase production, modified Luedeking–Piret model simulated experiments were further conducted with 1.5% (w/v), 3.29% (w/v) and 4% (w/v) NPW concentrations. The developed kinetic model perfectly captured the trends of biomass production, substrate consumption and adsorption characteristic of cellulase enzyme on its activity during production. The rate constant for cellulase synthesis was evaluated to be increased to 0.040 IU g⁻¹ h ⁻¹ at 3.29% (w v⁻¹) of NPW concentration; however, it was further reduced to 0.024 IU g⁻¹ h ⁻¹ at higher NPW concentration of 4% (w v⁻¹).