Ethanol Production from Hydrolyzed Soybean Molasses

• Published in: Energy & fuels Vol. 26; no. 4; pp. 2310 - 2316
• Main Authors: Romão, Betânia B, da Silva, Francielle B, de Resende, Miriam M, Cardoso, Vicelma L
• Format: Journal Article
• Language: English
• Published: American Chemical Society 19.04.2012
• Subjects: Ethanol; Ethyl alcohol; Fermentation; Hydrolysis; Inoculum; Nitric acid; Pressure; Soybeans
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/ef201908j

The aim of this work was to produce ethanol using the acid hydrolysis of soybean molasses followed by alcoholic fermentation via submerged Saccharomyces cerevisiae. The influence of the acid type, pH, and absolute pressure of the hydrolysis on the ethanol yield and the total residual sugar concentration was evaluated using a factorial design (FD). The absolute pressure ranged from 1 to 2 atm; the pH ranged from 3 to 5; and three different acids were studied in the hydrolysis process: sulfuric, hydrochloric, and nitric acids. The experiments were conducted in an Applicon batch reactor with a useful volume of 1.5 L at a stirring speed of 230 rpm and with an inoculum concentration of 30 g/L. The inoculum volume used was 30% of the total volume. The best results, as determined by FD, were obtained at pH 4 and an absolute pressure of 1.5 atm for all of the acids studied. The highest ethanol yield was 46% for sulfuric acid, 48% for hydrochloric acid, and 54% for nitric acid. After the concentration of inoculum and the fermentation kinetics profiles were investigated, a 62% yield relative to the initial sugar content was obtained under optimum conditions after 14 h of fermentation and an inoculum concentration of 35 g/L.