Optimization of Corn steep Liquor as a Sole Substrate for Bioethanol Production using Saccharomyces Cerevisiae

Abstract

The sustainability of any symbolic development is hinged on renewable energy like bioethanol. This study investigated the applicability of corn steep liquor (CSL) as both carbon and nitrogen sources in bioethanol production using Saccharomyces cerevisiae. The CSL used was characterized to ascertain its physical and chemical properties. The CSL was first applied in place of yeast extract in the inoculum medium and later applied in the fermentation medium, acting as both carbon and nitrogen sources. Box-Behnken design was used to develop the optimal variables (time, substrate concentration (CSL ratio), and pH) affecting the fermentation process. From the results, the analyzed CSL sample contained a total carbon-to-n for bioethanol production using the Box-Behnken design are CSL of 17.70 (v/v), time of 22.8 h, and pH of 5 with a corresponding bioethanol amount of 17.70 (v/v), time of 22.8 h, and pH of 5 with corresponding bioethanol amount of 9.49 g/L and reducing sugar of 1.59 g/L. This study shows that CSL could serve a dual purpose as a carbon and nitrogen source in microbial fermentation process, thereby reducing the overall cost of setting up a bioethanol production plant.