Nutrients balance for hydrogen potential upgrading from fruit and vegetable peels via fermentation process

Area of Science:

• Biotechnology and Bioengineering
• Renewable Energy
• Waste Valorization

Background:

• Fruit and vegetable peels (FVPs) represent a significant waste stream with potential for bioconversion.
• Optimizing nutrient composition is crucial for maximizing hydrogen production through anaerobic fermentation.

Purpose of the Study:

• To investigate the impact of sole, dual, and multi-fermentation of FVPs on hydrogen production.
• To determine the optimal nutrient balance for maximizing hydrogen yield and bioprocess efficiency.

Main Methods:

• Batch fermentation experiments were conducted using various combinations of fruit and vegetable peels.
• Nutrient ratios (C/N, C/P), enzyme activities (amylase, protease, lipase), and microbial populations (Clostridium, Enterobacter) were analyzed.
• Volumetric hydrogen production, hydrogen content, net energy gain, and profit were quantified.

Main Results:

• Multi-fermentation of a specific FVP mix (M-PTBO: pea, tomato, banana, orange) yielded the highest volumetric hydrogen production (2.55 L/L) and hydrogen content (64.7%).
• Balanced nutrient ratios in multi-fermentation supported enhanced activities of key enzymes and increased populations of hydrogen-producing bacteria.
• The M-PTBO multi-fermentation achieved maximum net energy gain (1.82 kJ/g) and profit ($4.11/kg).

Conclusions:

• Nutrient balancing through multi-fermentation of FVPs is a highly effective strategy for maximizing hydrogen production.
• Optimized fermentation conditions significantly enhance microbial activity, enzyme function, and overall bioprocess economics.
• This approach offers a sustainable method for waste valorization and renewable energy generation.