Production of coumaric acid from sugarcane bagasse

Phenolic acids were released from sugarcane bagasse by alkaline hydrolysis at 30 °C for 4 h; The alkaline hydrolysates were ultrafiltrated, the permeates purified with anion exchange resin. The phenolic acids bound by the resin were desorbed by a mixture of water–ethanol–HCl solution (36: 60: 4) after washing the resin with water, ethanol and dilute HCl respectively. The combined eluents were concentrated for crystalization, and the crystals filtered and washed using 1% (v/v) HCl. After this purification process, the purity of products reached 89.7% based on coumaric acid. Results of HPLC/MS, HPLC using standard coumaric acid and ferulic acid showed that the main component of the purified bagasse hydrolysate was p-coumaric acid rather than ferulic acid. The purified products showed the same antioxidant activity, reducing power and free radical scavenging capacity as the standard p-coumaric acid.The technology could be applied on industrial scale.Industrial relevanceThis research presents a technology to produce coumaric acids from sugarcane bagasse. The first step is to release coumaric acid by alkaline hydrolysis. The second step is to remove the viscous polysaccharides and protein by ultrafiltration. The third step is to purify coumaric acid from the permeate of ultrafiltration by anion chromatography, and the alkaline could be reused to hydrolyze the bagasse. The technology showed potential application on industrial scale.