Production of ethanol, phenolic acids, and hyaluronic acid after fractionation of sugarcane straw using organosolv pretreatment

Sugarcane straw, a byproduct of the sugarcane industry, holds significant potential for producing high-value bioproducts. In this study, we investigated the production of cellulosic ethanol, hyaluronic acid, and phenolic acids through the fractionation of sugarcane straw. Pretreatments were optimized by varying temperature (160, 190, and 220 degrees C), time (10, 30, and 50 min), and glycerol:water ratio (0%, 10 %, and 20% v/v). The pretreated samples were converted into ethanol using semi-simultaneous saccharification and fermentation (SSSF). The optimal pretreatment (220 degrees C, 50 min, 20% glycerol) resulted in a significant increase in cellulose content (from 34.27% to 61.26%) and glucose release (from 3.00 to 21.31 g/L). The maximum ethanol production (31.12 g/L) was achieved using 15 % (w/v) solids. The residual glycerol of the liquid fraction was efficiently utilized as a carbon source, resulting in a hyaluronic acid concentration of 1.72 g/L. Alkaline hydrolysis of SSSF solid residue produced a phenolic-rich extract with yields of up to 4645 mg total phenolic compounds, 1284 mg p-coumaric acid, and 375 mg ferulic acid per 100 g of substrate. This study demonstrates an integrated and effective route for the industrial valorization of sugarcane straw, contributing to sustainability and efficient utilization of agroindustrial byproducts.