Biochar enhanced high-solid mesophilic anaerobic digestion of food waste: Cell viability and methanogenic pathways

Yuxuan Cui; Feijian Mao; Jingxin Zhang; Yiliang He; Yen Wah Tong; Yinghong Peng

doi:10.1016/j.chemosphere.2021.129863

Biochar enhanced high-solid mesophilic anaerobic digestion of food waste: Cell viability and methanogenic pathways

Chemosphere. 2021 Jun:272:129863. doi: 10.1016/j.chemosphere.2021.129863. Epub 2021 Feb 9.

Authors

Yuxuan Cui¹, Feijian Mao², Jingxin Zhang³, Yiliang He⁴, Yen Wah Tong⁵, Yinghong Peng⁶

Affiliations

¹ China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai, 201306, China.
² NUS Environmental Research Institute, National University of Singapore, Singapore, 138602, Singapore.
³ China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai, 201306, China. Electronic address: lcczjx@sjtu.edu.cn.
⁴ China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai, 201306, China; School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China. Electronic address: ylhe@sjtu.edu.cn.
⁵ NUS Environmental Research Institute, National University of Singapore, Singapore, 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, 117585, Singapore.
⁶ School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; National Engineering Research Center for Nanotechnology, Shanghai, 200241, China.

PMID: 33588141
DOI: 10.1016/j.chemosphere.2021.129863

Abstract

The underlying mechanisms of biochar enhance high-solid anaerobic digestion (HSAD) of food waste were investigated with a focus on the cell viability, microbial community, and methanogenic pathways. This study assessed the effects of different dosages of biochar in HSAD. Optimal biochar dosage was found to be 25 g/L, which produced accumulative methane yields of up to 251 mL CH₄/g VS significantly promote volatile fatty acid degradations, especially in butyric acid concentrations. Effects of biochar with a dosage of 25 g/L on the cell viability showed that viable cells based on cell membrane integrity increased from 2.9% to 6.4%. Meanwhile, intact and highly active cells with high DNA content were probably involved in direct interspecies electron transfer (DIET) via membrane-bound electron transport proteins. Further analysis demonstrated that Syntrophomonas and methanogens Methanosarcina &Methanocelleus were selectively enriched by biochar, which resulted in the methanogenic pathways shifting from acetoclastic/hydrogenotrophic methanogenic pathways to more metabolically diverse methanogenic pathways. Accordingly, biochar-mediated DIET was possibly established between Syntrophomonas and Methanosarcina species due to those viable cells. In conclusion, biochar is a feasible additive in enhancing HSAD methanogenic performance.

Keywords: Biochar; Cell viability; Food waste; High-solid anaerobic digestion; Methanogenic pathways.

MeSH terms

Anaerobiosis
Bioreactors
Cell Survival
Charcoal
Food*
Methane
Refuse Disposal*

Substances

biochar
Charcoal
Methane