Corn-derived Expansin synergistically promotes enzymatic hydrolysis of corn cob

The enzymatic hydrolysis of lignocellulose is hindered by challenges such as high enzyme usage and associated costs. It is essential to explore effective approaches to improve the efficiency of enzymatic hydrolysis while reducing costs. Expansins are non-enzymatic proteins that can interact with lignocellulose and facilitate the loosening of plant cell walls. Given their natural affinity to plant cell walls, we hypothesized that a corn Expansin could enhance the enzymatic hydrolysis of corn lignocellulose. In this study, we expressed a corn (Zea mays) Expansin, EXPA17, in yeast cells and explored the synergistic effect between EXPA17 and commercial cellulase, and found that EXPA17 exhibited a pronounced synergistic effect on the enzymatic hydrolysis of corn cobs. The addition of 0.015 mg/mL EXPA17 resulted in a 14.00 % increase in glucose yield. Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analysis revealed that EXPA17 proteins disrupted hydrogen bonds in the amorphous regions of corn cobs, leading to a more porous and looser structure, thereby enhancing cellulose accessibility. Our work leveraged the synergistic effect between Expansin and lignocellulose from the same source of corn, providing a novel strategy to improve the efficiency of enzymatic hydrolysis of corn lignocellulose while potentially reducing the associated costs.