Biohydrogen production as a function of pH and substrate concentration

Area of Science:

• Biotechnology and Bioengineering
• Environmental Science and Engineering
• Renewable Energy Research

Background:

• Wastewater treatment presents challenges in organic waste management.
• Hydrogen gas is a clean energy source with potential for production from organic waste.
• Microbial conversion of organic matter offers a sustainable pathway for resource recovery.

Purpose of the Study:

• To investigate the recovery of chemical energy from sucrose-rich synthetic wastewater as hydrogen gas.
• To optimize hydrogen gas production by evaluating the effects of pH and substrate concentration.
• To identify suitable microbial consortia for efficient hydrogen generation from wastewater.

Main Methods:

• Utilized fractional factorial design in batch experiments to analyze process parameters.
• Employed mixed bacterial cultures from diverse environmental sources (compost, potato field, soybean field).
• Applied heat treatment to enrich for spore-forming, hydrogen-producing acidogenic bacteria and inhibit methanogens.

Main Results:

• The highest hydrogen production rate achieved was 74.7 mL H2/(L*h) at pH 5.5 and 7.5 g COD/L substrate concentration.
• A conversion efficiency of 38.9 mL H2/(g COD/L) was observed under optimal conditions.
• The maximum observed conversion efficiency reached 46.6 mL H2/(g COD/L).

Conclusions:

• Microbial conversion of organic wastewater is a viable method for simultaneous waste reduction and renewable energy (hydrogen) production.
• Optimized pH and substrate concentration are critical factors for maximizing hydrogen yield and production rates.
• Enriched microbial consortia demonstrate significant potential for efficient biohydrogen generation from synthetic wastewater.