Efficient enzymatic saccharification of agricultural wastes for the production of bioethanol, D-allulose and lactic acid

Abstract

The demand for renewable resources to replace fossil fuels has increased. Fruit and agricultural wastes can be fermented to yield biofuels and biochemicals. However, the high cost of the feedstock and limitations of the catalytic process hinder the application of such wastes. Therefore, we aimed to develop an efficient enzymatic saccharification process, without pretreatment, for fruit and agricultural wastes. The conversion rate of the mixed agricultural wastes (MAW) to fermentable sugars was approximately 91 % after 24 h. The ethanol yield increased by 4.5 % after limonene removal. The D-allulose yield in the hydrolysate was 4.6 mg/mL at 4 °C and 3.3 mg/mL at 50 °C, whereas the fructose yield in the sugar medium was 13.2 mg/mL at 4°C, demonstrating a high conversion yield of 73.2 %. Lactic acid was produced at a conversion rate of approximately 67.4 %. Therefore, this study presents a novel approach of the biosynthesis of functional sugars and chemicals from waste biomass, introducing a cost-effective enzymatic saccharification process that bypasses pretreatment, thereby enabling the production of biofuels, biochemicals, and functional sugars and opening up a promising economic opportunity in the field.