Utilization of corncob waste as bioethanol raw material by activities of Dekkera Bruxellensis and Saccharomyces Cerevisiae

Abstract

Corncob waste is not managed properly has the potential to environmental pollution. The purpose of this reasearch is to utilize corncob waste as a potential biomass into bioethanol. Process of making bioethanol is carried out in 4 steps, namely delignification, hydrolysis, fermentation, distillation. Corncob as substrate were prepared mechanically to become size powder 40 mesh. Delignification by fungi Dekkera Bruxellensis was varied with substrate ratio of 5, 10, and 15 grams at contact times of 3, 5, and 7 days. Hydrolysis with 2% sulfuric acid (H2SO4) at contact times of 30, 45, and 60 minutes. Glucose concentration was measured uing 3, 5-dinitrosalicylate (DBS) method. Variations of fungi:ragi = 1:1 at contact times of 3, 5, and 7 days. Distillation at temperature of 78°C using Gas Chromatography-Mass Spectrophotometry (GC-MS). This result in optimum delignification at substrate variation of 5 grams at contact time of 7 days, with a lignin removal 20,72%. The optimum glucose concentration in hydrolysis produced 7,561 g/L glucose at 2% Sulfuric acid (H2SO4). The highest ethanol content of 2,95% occured in ratio fungi:yeast 1:1 with substrate of 5 grams during 7 days. Based on pilot scale calculation with diameter 1,9 m and height of 0,9 m, then for 100 kg of corncobs can be produce 4,133L total ethanol.