Enhanced extraction of phytic acid from rice hulls with enzymatic treatment and production of ethanol from reducing sugars in hydrolyzed rice hulls after extraction of phytic acid

The physicochemical and enzymatic factors for the extraction of the phytic acid from rice hulls were investigated with the statistical methodology. The sequentially enzymatic treatment resulted in the enhanced extraction of the phytic acid from rice hulls. The extraction of the phytic acid from rice hulls with sequentially enzymatic treatment was 1.36 times higher than that without the enzymatic treatment. The maximum extraction of the phytic acid from rice hulls was 2.97 g/L with the extraction yield of 2.28%. The production of reducing sugars from partially hydrolyzed rice hulls after the extraction of phytic acid was also investigated. Optimal conditions of the amount of partially hydrolyzed rice hulls, the concentration of hydrochloric acid, the amount of cellulase, and the time for enzymatic reaction were 184.1 g/L, 2.3%, 253.2 U/mL, and 2.0 h, respectively. The maximum production of reducing sugars from the partially hydrolyzed rice hulls was 48.0 g/L with the conversion yield of 26.1%. The production of the ethanol by Scheffersomyces stipites ATCC 58785 from 48.0 g/L reducing sugars was 25.0 g/L. The extracted phytic acid and the produced ethanol can be used to develop for the functional materials and the beverage containing phytic acid.