Careful CO Addition Enhances Autotrophic d ‐Lactate Formation With Engineered Acetobacterium woodii
Year: 2026
Type: article
Abstract: ABSTRACT The acetogen A. woodii efficiently converts CO 2 and H 2 to acetate. Metabolic engineering enabled the autotrophic production of non‐native products, for example, d ‐lactate from CO 2 by overexpression of d ‐lactate dehydrogenase from Leuconostoc mesenteroides and knockout of the native lactate dehydrogenase. During gas fermentation with acetogens, the addition of CO leads to increased provision of reducing equivalents, and thus increased biomass formation. However, literature data reveal that already small CO partial pressures in the gas phase inhibit the autotrophic growth of A. woodii . This study aims to investigate adding 0.6%–6.0% CO to batch‐operated stirred tank bioreactors with continuous gassing to study autotrophic growth and product formation with the d ‐lactate producing A. woodii mutant. No growth and product formation were observed with 6% CO. Surprisingly, cell growth and metabolic product concentrations are non‐linearly dependent on lower CO concentrations in the inlet gas phase. Highest biomass concentrations were observed with 3% CO (3.24 g L −1 , 89% improvement compared to the reference process without CO addition), and the highest d ‐lactate accumulation was achieved with 0.8% CO (6.2 g L −1 d ‐lactate, 189% improvement compared to the reference without CO) after a prolonged lag phase. In conclusion, CO‐sensitive A. woodii cells need tight control of CO in syngas to affect autotrophic product selectivities.
Source: Engineering in Life Sciences
DOI: 10.1002/elsc.70072
Institutions: Technical University of Munich, Universität Ulm
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,300
OpenAlex ID: W7129248462