Nano magnetite-loaded biochar boosted methanogenesis through shifting microbial community composition and modulating...

Area of Science:

• Environmental Science
• Biotechnology
• Materials Science

Background:

• Anaerobic fermentation is crucial for biogas production.
• Propionate-degrading consortia (PDC) play a key role in methane generation.
• Improving the efficiency of PDC is essential for enhanced biogas yields.

Purpose of the Study:

• To investigate the impact of nano magnetite-loaded biochar on the methanogenic performance of PDC.
• To understand the mechanisms by which nano magnetite-loaded biochar enhances methane production.
• To explore the use of household waste and biogas residue in creating functional biochar.

Main Methods:

• A batch anaerobic fermentation system was utilized.
• Nano magnetite-loaded biochar was synthesized using household waste (HW) and biogas residue (BR) via hydrothermal and pyrolysis methods.
• Comprehensive characterization of biochar properties (specific surface area, electrochemical response, electron transfer resistance) was performed.
• Methanogenic performance of PDC with and without biochar addition was evaluated.

Main Results:

• Nano magnetite-loaded biochar exhibited improved properties, including a large specific surface area, high electrochemical response, and low electron transfer resistance.
• PDC supplemented with magnetite/BR-originated biochar composites showed a 1.6-fold enhancement in methane production rate compared to the control.
• The enhanced performance is attributed to the promotion of direct interspecies electron transfer (DIET) between syntrophic bacteria and methanogens.

Conclusions:

• Nano magnetite-loaded biochar is an effective enhancer for the methanogenic performance of propionate-degrading consortia.
• Magnetite facilitates extracellular electron release, while biochar acts as an electron bridge, promoting DIET.
• This study demonstrates a novel approach for waste valorization and biogas production enhancement.