Rice Bran Biorefinery: A Zero-Waste Approach to Bioactive Oil and Biopolymer Production

This research explores the valorization of rice bran, a significant byproduct of rice production, using a biorefinery model. The process began with the ethanolic extraction of rice bran oil, yielding 20.58% oil rich in bioactive compounds. This oil, evaluated through both in vitro and in vivo trials, has demonstrated effectiveness when combined with edible coatings, reducing post-harvest damage in grapes and lemons by 15-20%. Following extraction, the remaining defatted rice bran, accounting for 79.42% of the initial material, was used as a carbon-rich substrate for microbial fermentation. This step converts 28.75% of rice bran into microbial biomass and 12.75% into polyhydroxybutyrate-valerate. The undigested residual biomass, comprising 37.95% of the starting material, was further valorized through the purification of high value-added products such as cellulose (13.08%), hemicellulose (14.58%), and lignin (10.29%). Integrating these cascade processes within a biorefinery framework demonstrates the potential for comprehensive valorization of rice bran, aligning with circular economy principles.