Strategy for dual production of bioethanol and d-psicose as value-added products from cruciferous vegetable residue

In this study, fermentable sugars and d-fructose were produced from cruciferous vegetable residue by enzymatic method without the use of either chemical or mechanical mechanisms. Production of d-psicose was effectively converted from hydrolyzed d-fructose in cabbage residue by d-psicose-3 epimerase; the presence of the borate increased the conversion rate by about two fold, and ethanol production yield was 85.7% of the theoretical yield. Both products, bioethanol and d-psicose, were successfully separated and purified by pervaporation and cation exchange chromatography, and their recovery yields were approximately 87% and 86.2%, respectively.