Bioethanol production from waste potatoes as an environmental waste management and sustainable energy by using cocultures Aspergillus niger and Saccharomyces cerevisiae

Fermentation of unhydrolyzed potato waste to ethanol by cocultures of Aspergillus niger and Saccharomyces cerevisiae was investigated at different temperatures (20°C to 50°C) and at different pH (4 to 7). Fermentation was done for 7 days for potato waste and the ethanol content was measured every 24 hours. The optimum pH and temperature for the fermentation of waste potatoes was found 6 and 30°C. With the optimized pH and temperature, fermentation was then carried out at different yeast concentration 3% to 12%. With the change in the concentration of yeast, the time required for the completion of fermentation decreased dramatically. Using a 12%, 9%, 6%, 3% yeast inoculum, maximum ethanol production was completely achieved in 2, 3, 5, 7 days respectively. The maximum ethanol yield from waste potatoes was 12.124%. Aspergillus niger strain B gave a higher production of ethanol. The amount of ethanol content increased with the increase in fermentation time.