Study of high solid loading enzymatic hydrolysis of sodium bisulphite pretreated corncob residue and kinetic modeling

In this study, sodium bisulfite (NaHSO₃) pretreatment was employed to overcome the limitations of corncob residue in high solid loading enzymatic hydrolysis by introducing hydrophilic sulfonic acid groups (-SO₃H) into lignin aromatic rings via sulfonation reactions, which significantly enhanced substrate accessibility. Furthermore, to enhance the precision of glucose concentration prediction during high solid loading enzymatic hydrolysis of NaHSO₃ pretreated corncob residue, we developed a novel kinetic model. It introduced a substrate characteristic parameter (b) and revised the traditional fractal parameters h and k. This model demonstrated noteworthy prediction capabilities across a broad spectrum of solid loadings (2%-24%), enzyme dose gradients (5-20 FPU/g), and shaking speeds (100-200 rpm). Compared with the traditional fractal model, it not only achieved a higher R² (>0.9927) but also reduced the prediction error substantially, especially under high solid loading conditions. A variety of lignocellulosic biomasses were pretreated using NaHSO₃, NaOH/H₂O and NaOH/ethanol, and the model predicted glucose concentration in these pretreated solids with a high degree of accuracy. The findings demonstrated that the model was a valuable instrument for the precise control of lignocellulosic biorefinery processes, thereby enhancing the controllability and economic efficiency of high solid loading enzymatic processes.