Selective formate production from H2 and CO2 using encapsulated whole-cells under mild reaction conditions

• Published in: Journal of bioscience and bioengineering 2023-09, Vol.136 (3), p.182-189
• Main Authors: Nguyen, Hung Khac, Minato, Takuo, Moniruzzaman, Mohammad, Kiyasu, Yu, Ogo, Seiji, Yoon, Ki-Seok
• Format: Article
• Language: English
• Subjects: CO2 hydrogenation; CO2 reduction; Encapsulation of cell; Formate production; H2 oxidation; Mild reaction condition; Resting-cell; Whole-cell biocatalyst
• ISSN: 1389-1723; 1347-4421
• DOI: 10.1016/j.jbiosc.2023.06.002

Biocatalytic CO2 reduction into formate is a crucial strategy for developing clean energy because formate is considered as one of the promising hydrogen storage materials for achieving net-zero carbon emissions. Here, we developed an efficient biocatalytic system to produce formate selectively by coupling two enzymatic activities of H2 oxidation and CO2 reduction using encapsulated bacterial cells of Citrobacter sp. S-77. The encapsulated whole-cell catalyst was made by living cells depositing into polyvinyl alcohol and gellan gum cross-linked by calcium ions to form hydrogel beads. Formate production using encapsulated cells was carried out under the resting state conditions in the gas mixture of H2/CO2 (70:30, v/v%). The whole-cell biocatalyst showed highly efficient and selective catalytic production of formate, reaching the specific rate of formate production of 110 mmol L−1· gprotein−1·h−1 at 30 °C, pH 7.0, and 0.1 MPa. The encapsulated cells can be reused at least 8 times while keeping their high catalytic activities for formate production under mild reaction conditions. Selective formate production from H2 and CO2 using encapsulated whole-cells with polyvinyl alcohol and gellan gum cross-linked by calcium ions. [Display omitted] •Robust encapsulated whole-cell biocatalysts by using gellan gum and polyvinyl alcohol.•Utilization of gene clusters involving H2 and formate metabolism and formate channel for a biocatalytic system.•Encapsulated biocatalysts for selective formate production under resting state reaction conditions.