Bioconversion of Lignocellulosic Biomass into Xylitol and Ethanol Using Kluyveromyces and Saccharomyces cerevisiae

Abstract

The sustainable utilization of lignocellulosic agricultural residues represents a promising approach to producing renewable bio-based chemicals and reducing environmental pollution caused by open-field burning. This study aimed to evaluate sugarcane bagasse, wheat straw, and corn cob as low-cost substrates for the biotechnological production of Xylitol and Ethanol. The biomass was subjected to sequential Acid and Alkali Hydrysis, and Enzymatic Saccharification to maximize the release of fermentable sugars, followed by fermentation with Kluyveromyces (pentose-fermenting yeast) and Saccharomyces cerevisiae (hexose-fermenting yeast). Alkali-enzyme pretreatment of sugarcane bagasse liquor released the highest concentrations of xylose (36.27 g/L) and glucose (6.21 g/L). Fermentation with Kluyveromyces yielded a maximum xylitol concentration of 28.54 g/L with 78.68 % yield and volumetric productivity of 0.016 g/L/h, whereas S. cerevisiae fermentation of sugarcane bagasse residue produced 4.26 g/L ethanol with 69.40 % yield and 0.236 g/L/h productivity. Wheat straw alkali–enzyme hydrolysate demonstrated the highest Xylitol yield (121.29 %) at pH 6, indicating the influence of pH on process efficiency. These findings demonstrate that integrated chemical hydrolysis and enzymatic saccharification substantially enhances sugar recovery and subsequent microbial conversion into value-added products. The results highlight the potential of using agro-industrial residues as a sustainable feedstock for biorefineries. Future studies should focus on process optimization, detoxification of hydrolysates, and techno-economic assessments to enable industrial-scale, cost-effective production of Xylitol and Ethanol.