Bio-hythane production from cassava residue by two-stage fermentative process with recirculation

Area of Science:

• Biotechnology
• Anaerobic Digestion
• Microbial Metabolism

Background:

• Two-stage hythane fermentation of protein-deficient cassava residue failed due to nutrient imbalance.
• Observed issues included decreased methane production and volatile fatty acids accumulation.

Purpose of the Study:

• To investigate the impact of nutrient supplementation on hythane fermentation of cassava residue.
• To identify optimal nutrient levels for sustainable and efficient hythane production.

Main Methods:

• Repeated batch and continuous fermentation experiments were conducted.
• Nutrient content analysis and microbial community assessment were performed.
• Additions of nitrogen, sulfur, nickel, and cobalt were tested.

Main Results:

• Supplementation with N (0.7g/L), S (30mg/L), Ni (1.0mg/L), and Co (1.0mg/L) restored microbial proliferation and fermentation metabolism.
• The optimal nutrient combination led to the highest hythane yield of 426m³ per ton of cassava residue.
• The produced hythane contained 27.7% hydrogen.

Conclusions:

• Cassava residue requires specific nutrient supplementation for successful hythane fermentation.
• Optimized nutrient ratios are crucial for sustaining microbial activity and maximizing hythane yield.
• This study provides a framework for enhancing biofuel production from lignocellulosic biomass.