Enhancing Second-generation Ethanol Production Through Acid Hydrolysis and Saccharomyces Cerevisiae Fermentation: a Sustainable Approach Using Cassava Peel and Manipueira Biomass

Abstract

The biofuel derived from controlled fermentation and subsequent distillation of lignocellulosic biomass is commonly referred to as second-generation ethanol (2G). This energy production pathway has experienced exponential growth due to its dual role as an alternative additive to fossil fuels and a potential replacement for this environmentally detrimental energy source in the future. This study aimed to produce second-generation ethanol by utilizing cassava peel and manipueira through acid hydrolysis, followed by a 10-day fermentation process using the yeast Saccharomyces cerevisiae the fermenting microorganism. The process began with the mechanical pulverization of the biomass, followed by a triple round of acid hydrolysis using sulfuric acid at 100 °C for 10 minutes. Subsequently, fermentation occurred within sealed PET bottles, with each sample containing 10 g of yeast and 25 g of biomass, maintaining a 1:2.5 mass ratio of yeast to biomass, at an average room temperature of 35 °C for 10 days. After this incubation period, the fermented solutions were evaluated for °BRIX and pH levels, then filtered using a vacuum pump and distilled in a micro distillation apparatus to obtain ethanol 2G. The obtained results demonstrated the significant potential of cassava peel (Manihot esculenta) and manipueira biomass for second-generation ethanol production, with °Brix values of 4 % for cassava peel and 3% for manipueira, respectively. During the fermentation process, regular assessments of pH, sugar content, alcohol concentration, and corresponding ethanol mass percentage were conducted for each sample. These analyses revealed a gradual increase in alcohol levels over time, reaching a peak of 26.2 % for cassava peel and 24 % for manipueira after 10 days. These findings suggest that cassava and manipueira peels, as sources of lignocellulosic biomass, hold promise for second-generation ethanol production. This research directly contributes to the development of more efficient and sustainable processes for generating biofuels from agricultural waste, paving the way to produce clean and renewable energy.