Efficient Production of Second-Generation Ethanol Through Direct Fermentation Utilising Saccharomyces cerevisiae with Sweet Potato Peels, Beet Peels, and Sugarcane Bagasse Juice as Feedstocks

Abstract

This study aimed to investigate the potential for producing second-generation (2G) ethanol from sweet potato peels, beet peels, and sugarcane bagasse without hydrolysis. The process involved direct fermentation using Saccharomyces cerevisiae for different time intervals (36, 48, 72, and 168 hours). The raw materials were mixed with water and heated up to 105°C for 30 minutes. The fermentation process was carried out in sealed PET bottles kept at 25 °C, using 10 g of Saccharomyces cerevisiae and 200 g of biomass (at a mass ratio of 1:20). Measurements of °BRIX and pH were taken at each fermentation interval. After fermentation, the mixture was filtered and distilled to obtain bioethanol. The study found that sweet potato and beet peel biomasses showed significant potential. Regular monitoring of pH, sugar content, alcohol content, and bioethanol percentage was conducted. The mixture was heated to the boiling point of ethanol (78.37 °C) after distillation. The maximum bioethanol weight percentage (wt%) achieved was 18.58% (36 hours), 17.56% (48 hours), and 16.73% (72 hours) for beet peel, sugarcane bagasse juice, and sweet potato peel, respectively. This study highlights the promising prospects of using lignocellulosic biomasses for 2G ethanol production, which contributes to sustainable biofuel processes and paves the way for clean and renewable energy generation.