Formate Utilization by the Crenarchaeon Desulfurococcus amylolyticus

Area of Science:

• Microbiology
• Biochemistry
• Archaea Metabolism

Background:

• Formate is crucial in microbial carbon and energy metabolism, particularly in anaerobic syntrophic associations.
• It holds potential as an energy storage compound in biotechnology.
• Microbial growth on formate is documented in bacteria and archaea, but not previously in Crenarchaeota.

Purpose of the Study:

• To investigate formate metabolism in the anaerobic, hyperthermophilic Crenarchaeon Desulfurococcus amylolyticus.
• To determine the metabolic pathways utilized by D. amylolyticus for formate assimilation.
• To explore the metabolic versatility within the archaeal phylum Crenarchaeota.

Main Methods:

• Cultivation of Desulfurococcus amylolyticus on formate, glucose, and glucose/formate mixtures.
• Analysis of growth, substrate uptake, and production kinetics.
• Whole-cell conversion experiments to identify formate metabolites.
• Bioinformatic analysis of potential formate utilization pathways.

Main Results:

• Desulfurococcus amylolyticus metabolizes formate without producing molecular hydrogen.
• Growth kinetics and cell densities were similar across different substrates (formate, glucose, mixtures).
• Formate was converted to carbon dioxide, acetate, citrate, and ethanol.
• Bioinformatic analysis suggests formate assimilation via formaldehyde and the oxidative pentose phosphate pathway.

Conclusions:

• Desulfurococcus amylolyticus exhibits unique formate metabolism, distinct from hydrogen-producing pathways.
• The proposed pathway involves formaldehyde dehydrogenase and the oxidative pentose phosphate pathway for formate assimilation.
• These findings expand our understanding of the metabolic capabilities of Crenarchaeota.