Unravelling the Chemolithoautotrophic Metabolism of the Carboxydotrophic Knallgas Bacterium Hydrogenophaga pseudoflava.
7 affiliations
- 1Microbial Biotechnology, Campus Straubing for Biotechnology and Sustainability, Technical University of Munich, Straubing, Germany.
- 2Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, Australia.
- 3ARC Centre of Excellence in Synthetic Biology, The University of Queensland, Brisbane, Queensland, Australia.
- 4Advanced Engineering Biology Future Science Platform, CSIRO, Brisbane, Queensland, Australia.
- 5Chair of Chemistry of Biogenic Resources, Campus Straubing for Biotechnology and Sustainability, Technical University of Munich, Straubing, Germany.
- 6Catalytic Research Center, Technical University of Munich, Garching, Germany.
- 7SynBiofoundry@TUM, Technical University of Munich, Straubing, Germany.
Abstract
The sustainable production of chemicals is critical to reducing greenhouse gas emissions and environmental pollution. Gaseous feedstocks from industrial waste streams and waste gasification, including CO, CO₂ and H₂, represent abundant and underutilized resources for biotechnology. Syngas fermentation has been predominantly studied under anaerobic conditions, whereas aerobic processes may offer advantages for the biosynthesis of energy-intensive products. One promising organism is the aerobic carboxydotroph Hydrogenophaga pseudoflava DSM 1084, whose chemolithoautotrophic metabolism remains poorly understood. To address this, we performed proteome analysis under different growth conditions and characterized deletion mutants of key enzymes involved in CO and H₂ oxidation. Deletion mutants showed that only CO dehydrogenase I and the membrane-bound hydrogenase are essential for CO and H₂ oxidation, respectively. The role of the putative second CO dehydrogenase remains to be elucidated, and the soluble hydrogenase may contribute to redox balancing under microaerobic or anaerobic conditions. In addition, the H₂-sensing regulatory system appears to be nonfunctional, and the transhydrogenase PntAB supports redox homeostasis during chemolithoautotrophic growth. Electrons from CO or H₂ are transferred via the reduced quinone pool to NADH through proton-motive force-driven reverse electron transfer. Nevertheless, growth on CO remains slower than on CO₂/H₂. In contrast to CO₂/H₂, an unphysiologically high CO concentration (80%) led to a major proteome rearrangement, with 1879 of 3640 reliably quantified proteins showing altered abundance compared to fructose-grown cells, including a pronounced stress response. Under such conditions, cells are likely to invest additional energy to maintain redox balance. Together with the less energy-conserving autotrophic branch of the respiratory chain and cytoplasmic CO oxidation, this results in inefficient CO conversion and reduced growth.
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BibTeX
@article{grieshaber2026unravelling,
title = {{Unravelling the Chemolithoautotrophic Metabolism of the Carboxydotrophic Knallgas Bacterium Hydrogenophaga pseudoflava.}},
author = {Simon Grieshaber and Antonia Ebert and Pauline Kehr and Dominik L Siebert and Ammar Al-Shameri and Volker Sieber and Birgitta E Ebert and Esteban Marcellin and Bastian Blombach},
journal = {Microbial biotechnology},
year = {2026},
month = nov,
doi = {10.1111/1751-7915.70452},
url = {https://europepmc.org/article/MED/42968439},
note = {CC BY},
}
RIS
TY - JOUR
TI - Unravelling the Chemolithoautotrophic Metabolism of the Carboxydotrophic Knallgas Bacterium Hydrogenophaga pseudoflava.
AU - Simon Grieshaber
AU - Antonia Ebert
AU - Pauline Kehr
AU - Dominik L Siebert
AU - Ammar Al-Shameri
AU - Volker Sieber
AU - Birgitta E Ebert
AU - Esteban Marcellin
AU - Bastian Blombach
PY - 2026
DA - 2026/11/01
JO - Microbial biotechnology
DO - 10.1111/1751-7915.70452
UR - https://europepmc.org/article/MED/42968439
AB - The sustainable production of chemicals is critical to reducing greenhouse gas emissions and environmental pollution. Gaseous feedstocks from industrial waste streams and waste gasification, including CO, CO₂ and H₂, represent abundant and underutilized resources for biotechnology. Syngas fermentation has been predominantly studied under anaerobic conditions, whereas aerobic processes may offer advantages for the biosynthesis of energy-intensive products. One promising organism is the aerobic carboxydotroph Hydrogenophaga pseudoflava DSM 1084, whose chemolithoautotrophic metabolism remains poorly understood. To address this, we performed proteome analysis under different growth conditions and characterized deletion mutants of key enzymes involved in CO and H₂ oxidation. Deletion mutants showed that only CO dehydrogenase I and the membrane-bound hydrogenase are essential for CO and H₂ oxidation, respectively. The role of the putative second CO dehydrogenase remains to be elucidated, and the soluble hydrogenase may contribute to redox balancing under microaerobic or anaerobic conditions. In addition, the H₂-sensing regulatory system appears to be nonfunctional, and the transhydrogenase PntAB supports redox homeostasis during chemolithoautotrophic growth. Electrons from CO or H₂ are transferred via the reduced quinone pool to NADH through proton-motive force-driven reverse electron transfer. Nevertheless, growth on CO remains slower than on CO₂/H₂. In contrast to CO₂/H₂, an unphysiologically high CO concentration (80%) led to a major proteome rearrangement, with 1879 of 3640 reliably quantified proteins showing altered abundance compared to fructose-grown cells, including a pronounced stress response. Under such conditions, cells are likely to invest additional energy to maintain redox balance. Together with the less energy-conserving autotrophic branch of the respiratory chain and cytoplasmic CO oxidation, this results in inefficient CO conversion and reduced growth.
SN - 1751-7915
ER -