Biogas upgrading and valorization to single-cell protein in a bioinorganic electrosynthesis system

Mingyi Xu, Dan Zhao, Xinyu Zhu, Yanyan Su, Irini Angelidaki, Yifeng Zhang*

*Corresponding author for this work

    Research output: Contribution to journalJournal articleResearchpeer-review

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    Abstract

    Valorization of crude biogas to value-added products is the key step toward techno-economic biogas business. Besides, the increasing world population puts heavy pressure on food supply and will double protein demand in the coming decades. In this context, we propose a bioinorganic electrosynthesis process for the integration of biogas upgrading and edible single-cell protein production, which could be an alternative solution to address these challenges. With a biogas inflow of 70%CH4/30%CO2 at 50 mL·d−1 and an applied voltage of 3.0 V, the protein concentration of 472.04 ± 22.05 mg·L−1 was achieved with the “CO2-to-CH4” bioconversion efficiency of 92.97 ± 5.61%. Higher CO2 content in the biogas resulted in a comparatively lower protein concentration. The system was tested resilient to the toxic H2S in biogas (up to 5000 ppm). It was possible to improve the protein yield three times by scaling up the fermenter from 100 mL to 1 L, with a “CH4-to-SCP” fermentation efficiency of 70.67 ± 2.37%. The methanotrophic biomass produced in the system was found rich in protein with a total amino acids mass-content of over 62.8%. The outcomes of this study will offer a new solution for sustainable protein production, biogas upgrading and valorization, which are perfectly in line with the United Nations Sustainable Development Goals.
    Original languageEnglish
    Article number131837
    JournalChemical Engineering Journal
    Volume426
    Number of pages9
    ISSN1385-8947
    DOIs
    Publication statusPublished - 2021

    Keywords

    • Methane-oxidizing bacteria
    • Single-cell protein
    • Bioinorganic electrosynthesis
    • Biogas upgrading
    • Carbon capture and utilization
    • Renewable energy

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