Pretreatment of corn stover by solid acid for d-lactic acid fermentation

Area of Science:

• Biotechnology
• Green Chemistry
• Biomass Utilization

Background:

• Solid acids offer a safe and environmentally friendly alternative for industrial acid applications.
• Corn stover is an abundant lignocellulosic biomass with potential for value-added product generation.
• Efficient pretreatment is crucial for unlocking the fermentable sugars within corn stover.

Purpose of the Study:

• To optimize solid acid pretreatment conditions for corn stover.
• To evaluate the enzymatic hydrolysis efficiency of pretreated corn stover.
• To produce d-lactic acid using pretreated corn stover as a fermentation substrate.

Main Methods:

• Solid acid pretreatment of corn stover at varying temperatures, times, and concentrations.
• Enzymatic hydrolysis of pretreated corn stover using cellulase.
• Fermentation of glucose derived from pretreated corn stover using Lactobacillus delbrueckii sp. bulgaricus.
• Structural analysis using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR).

Main Results:

• Optimal solid acid pretreatment conditions determined: 120°C, 80 min, 1.5% solid acid concentration.
• Enzymatic hydrolysis achieved a glucose conversion rate of 71.06% after 72 hours with 30 FPU/g cellulase.
• Fermentation produced d-lactic acid with a yield of 18 g/L and 99% optical purity.

Conclusions:

• Solid acid pretreatment is an effective method for enhancing the saccharification of corn stover.
• Pretreated corn stover serves as a viable substrate for the microbial production of d-lactic acid.
• This research presents a sustainable pathway for the comprehensive utilization of corn stover in biorefineries.