Comparative analysis of bioethanol production from agricultural wastes using Saccharomyces cerevisiae, Aspergillus niger, and their co-culture

The present study aimed to analyze the proximate composition of waste potatoes, wheat straw, and sugarcane bagasse collected from various locations and to optimize fermentation variables for maximum bioethanol yield using Saccharomyces cerevisiae, Aspergillus niger, and their co-culture. Initially, the chemical composition of the substrates was analyzed, revealing that waste potatoes, wheat straw, and sugarcane bagasse contain significant levels of total soluble solids (TSS), making them suitable for bioethanol production. Subsequently, experiments were conducted to maximize ethanol yield by varying fermentation parameters. The substrates were tested at different TSS levels (18°Brix, 20°Brix, and 22°Brix), pH levels (3.5, 4.0, and 4.5), and incubation temperatures (27 °C, 30 °C, and 33 °C) using the three microbial cultures individually and in co-culture. Experimental findings demonstrated that the co-culture of Saccharomyces cerevisiae and Aspergillus niger efficiently produced ethanol across various substrates under optimal conditions of 20°Brix TSS, pH 4.0, and an incubation temperature of 30 °C. Among the tested substrates, sugarcane bagasse yielded the highest ethanol concentration at 6.1%, followed by waste potatoes at 5.7%, and wheat straw at 4.6%. These results highlight the superior efficiency of sugarcane bagasse for ethanol production, with the same co-culture and process parameters proving consistently effective across all substrates. This study underscores the potential of utilizing agricultural waste for sustainable bioethanol production and provides valuable insights into optimizing fermentation processes for maximum yield.