Cost-effective approach to ethanol production and optimization by response surface methodology

Area of Science:

• Biotechnology
• Biochemical Engineering
• Sustainable Chemistry

Background:

• Food waste presents a significant disposal challenge and an underutilized resource.
• Microbial fermentation of food waste offers a sustainable route for valuable product generation, potentially lowering costs.
• Utilizing mixed carbohydrate components in food waste for simultaneous hydrolysis and fermentation is an area of interest.

Purpose of the Study:

• To assess the potential of simultaneous hydrolysis and fermentation of mixed carbohydrates from kitchen waste for ethanol production.
• To optimize fermentation parameters including solid load, baker's yeast inoculum volume, and fermentation time using response surface methodology (RSM).
• To evaluate the economic feasibility of using kitchen waste as a substrate for bioethanol production.

Main Methods:

• Enzymatic hydrolysis of kitchen waste carbohydrates.
• Fermentation using baker's yeast under controlled conditions (pH 4.5, 30°C, 150 rpm).
• Optimization of solid load, inoculum volume, and fermentation time using Response Surface Methodology (RSM).

Main Results:

• Enzymatic hydrolysis was completed within 6 hours.
• RSM analysis identified significant linear and quadratic effects of solid load, inoculum volume, and fermentation time on ethanol production (P<0.05).
• Optimal conditions yielded 32.2 g/l ethanol with a yield of 0.40 g/g, using 20% solid load, 8.9% inoculum volume, and 58.8 hours of fermentation.

Conclusions:

• Kitchen waste is a viable substrate for ethanol production through simultaneous hydrolysis and fermentation.
• Optimized fermentation parameters significantly enhance ethanol yield and reduce production costs.
• Eliminating traditional fermentation nutrients and utilizing diverse carbohydrate sources in food waste contribute to cost-effective bioethanol production.