Effect of activated charcoal treatment of alkaline hydrolysates from sugarcane bagasse on purification of p-coumaric acid

The brown compounds in the ultrafiltration permeates resulting from the alkaline-hydrolysis of sugarcane bagasse were determined to be composed mainly of lignin monomers. These monomers significantly influence the separation and purification of p-coumaric acid. Addition of 3% of activated charcoal removed 78.10% of the compounds’ color value but adsorbed only 14.36% of the available coumaric acid in alkaline conditions. Decoloration by the application of activated charcoal before purification by anion exchange chromatography ensured the repeated use of the resins and crystallization of p-coumaric acid, thus significantly reducing preparation costs. A total of 8.56 g of crystal contained 95.2% of coumaric acid was obtained from 1 kg of sugarcane bagasse after decoloration and separation.

► Brown compounds are usually produced after alkaline-hydrolysis of sugarcane bagasse and other fiber-containing agro by-products. ► We determined them mainly as lignin monomers. ► Activated charcoal could remove most of them. ► High-purity coumaric acid after activated charcoal adsorption was prepared by anion exchange chromatography.