Feasibility of bioethanol production from rice bran

Abstract

Rice bran is a by-product of rice production with a high carbohydrate and starch content and the potential for bioethanol production by alcoholic fermentation. This article describes bioethanol production by Saccharomyces cerevisiae from hydrolyzed defatted rice bran (DRB) a rice by-product applying ultrasonic treatment and protease addition, as well as a sequential strategy of experimental design (SEED). In the first Central Composite Rotatable Design (CCRD), the temperature (25-30 °C) and inoculum concentration (0.5-50 g L-1) had positive effects on bioethanol production, while the effect of pH (4.0-6.0) was not significant. In the second CCRD, the temperature (28-35 °C) and inoculum concentration (10-70 g L-1) had negative and positive effects on bioethanol production (p < 0.05). Protease addition (15 µL g-1) increased the conversion of substrate into bioethanol by 76%. The optimized conditions for the production of 40.7 g L-1 bioethanol were a temperature of 31.5 °C and an inoculum concentration of 70 g L-1. Validation in a benchtop bioreactor produced 40.0 g L-1 of bioethanol from hydrolyzed DRB, and the SEED was characterized as a useful tool to improve bioethanol production from DRB. Furthermore, the DRB proved to be a by-product with great potential for bioethanol production, derived from alternative sources not commonly used in human food.

Application of acid protease in the industrial production of corn ethanol

“…With the development of economy, countries all over the world rely more and more on fossil energy. While human beings enjoy various conveniences, we are also facing problems, such as environmental pollution and energy exhaustion [1,2]. Fuel ethanol has become an ideal substitute for fossil fuels due to its environmentally friendly, renewable, mature technology and easy promotion.…”