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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Sustainable Biofuels and Co-products Research » Research » Publications at this Location » Publication #386200
Research Project: Chemical Conversion of Biomass into High Value Products

Location: Sustainable Biofuels and Co-products Research

Title: Adsorption or direct interspecies electron transfer? A comprehensive investigation of the role of biochar in anaerobic digestion of hydrothermal liquefaction aqueous phase

Author
item WANG, ZIXIN - University Of Illinois
item ZHANG, CHENG - University Of Illinois
item WATSON, JAMISON - University Of Illinois
item Sharma, Brajendra - Bk
item SI, BUCHUN - China Agriculture University
item ZHANG, YUANHUI - University Of Illinois

Submitted to: Chemical Engineering Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2022
Publication Date: 2/10/2022
Citation: Wang, Z., Zhang, C., Watson, J., Sharma, B.K., Si, B., Zhang, Y. 2022. Adsorption or direct interspecies electron transfer? A comprehensive investigation of the role of biochar in anaerobic digestion of hydrothermal liquefaction aqueous phase. Chemical Engineering Journal. https://doi.org/10.1016/j.cej.2022.135078.
DOI: https://doi.org/10.1016/j.cej.2022.135078

Interpretive Summary: Biochar could facilitate the anaerobic digestion of the water phase generated during the thermochemical conversion process. However, the role of the biochar hasn’t been elucidated well. Direct electron transfer between species, adsorption, and detoxification are some possible roles. This study was conducted to confirm the exact role of the biochar on the anaerobic digestion process. It was found that the total pore volume and adsorption capacity of the biochar played a big role. The electrical conductivity and electron transfer capacities were too poor to induce Direct electron transfer between species. The addition of biochar does affect organic conversion and methane generation through microbial composition and metabolic pathways. This information will not only improve the economic value of thermochemical conversion of biomass by increasing utilization of a waste byproduct of the process but will also help farmers by increasing the value of waste biomass generated on the farms.

Technical Abstract: Adding biochar could facilitate the anaerobic digestion of hydrothermal liquefaction aqueous phase (HTL-AP), but the role of biochar has not been explicitly claimed. Direct interspecies electron transfer (DIET) was proposed to participate and dominate the digestion process, while the adsorption and detoxification effects of biochar cannot be ignored. This study is conducted to confirm the exact role of biochar and its primary mechanism on the digestion process. Results showed that the total pore volume and adsorption capacity of biochar played the most influential role. However, the electrical conductivity and electron transfer capacities were too poor to induce DIET. Biochar affects organic conversion and methane generation by influencing the microbial composition and related metabolic pathways. And suppressive biochar can also lead to suppressed methane production. Thus, the effect of biochar addition on anaerobic digestion of HTL-AP relies mainly on adsorption and its impact on the microbial community and mediated interspecies electron transfer remains the primary mechanism rather than DIET.