Ethanol Fermentation of Cellulosic Hydrolysate from Sugarcane Bagasse to Develop Stand-Alone Second Generation Ethanol Plant

Abstract

In this study, the ethanol fermentation of cellulosic hydrolysate produced from hydrothermal pretreatment of sugarcane bagasse, followed by detoxification and enzymatic hydrolysis was investigated. It was conducted on fermentability, and nutrient supplementation requirement. Fermentability was evaluated through ethanol fermentation with cell recycle for eight sequencing batches. In the first cycle, glucose was converted mostly to ethanol and cells without nutrients addition. In the following batches, nitrogen and phosphate supplementation to achieve a successful fermentation was required. The kinetics of cell growth, substrate consumption and ethanol production during fermentation were described using a mechanistic model. Specific ethanolproductivity of 1.34 kg/m3.h, yield of 90 % and cell viability of 93 % were obtained. Nutrient supplementation was assessed using a central composite design to investigate the effect of molasses, urea and diammonium phosphate (DAP) addition on productivity. Statistical analysis showed that only the effect of molasses addition was significant on productivity at 95% confident level.