High-rate biohydrogen production from xylose using a dynamic membrane bioreactor

Area of Science:

• Biotechnology
• Renewable Energy
• Microbial Hydrogen Production

Background:

• Dark fermentation is a key process for biological hydrogen production.
• Xylose, derived from lignocellulose, is an abundant and underutilized carbon source.
• Efficient hydrogen production requires optimized bioreactor design and operational parameters.

Purpose of the Study:

• To investigate high-rate hydrogen production from xylose using a dynamic membrane module bioreactor (DMBR).
• To evaluate the effect of hydraulic retention time (HRT) on hydrogen yield and production rate.
• To analyze the microbial community dynamics and metabolic pathways involved.

Main Methods:

• Continuous fermentation of 20 g/L xylose in a DMBR with a 444-μm pore polyester mesh.
• Operation at varying HRTs (12 to 3 hours) and a constant temperature of 37°C.
• Analysis of hydrogen yield, production rate, biomass concentration, and microbial populations.

Main Results:

• Maximum hydrogen yield of 1.40 ± 0.07 mol H2/mol xylose consumed and production rate of 30.26 ± 1.19 L H2/L-d were achieved at 3-hour HRT.
• Short HRT promoted high suspended and attached biomass concentrations.
• Bacterial community shifted towards Clostridium species, correlating with increased hydrogen production and reduced lactic acid.

Conclusions:

• Dynamic membrane module bioreactors are effective for high-rate hydrogen production from xylose.
• Optimized short hydraulic retention times enhance hydrogen yield and production rates.
• Xylose from lignocellulose is a viable substrate for sustainable hydrogen generation via dark fermentation.