Ex-situ single-culture biomethanation operated in trickle-bed configuration: Microbial H kinetics and stoichiometry for biogas conversion into renewable natural gas.

Biomethanation converts carbon dioxide (CO) emissions into renewable natural gas (RNG) using mixed microbial cultures enriched with hydrogenotrophic archaea. This study examines the performance of a single methanogenic archaeon converting biogas with added hydrogen (H) into methane (CH) using a trickle-bed bioreactor with enhanced gas-liquid mass transport. The process in continuous operation followed the theoretical reaction of hydrogenotrophic methanogenesis (CO + 4 H → CH + 2 HO), producing RNG with over 99 % CH and more than 0.

Examining homoacetogens in feces from adult and juvenile kangaroos with the aim of finding competitive strains to hydrogenotrophic methanogens.

Unlabelled: We examined the microbial populations present in fecal samples of macropods capable of utilizing a mixture of hydrogen and carbon dioxide (70:30) percent. The feces samples were cultured under anaerobic conditions, and production of methane or acetic acids characteristic for methanogenesis and homoacetogenesis was measured. While the feces of adult macropods mainly produced methane from the substrate, the sample from a 2-month-old juvenile kangaroo only produced acetic acid and no methane.

Phenotypic and genomic characterization of strain BSEL, a CO-capturing archaeon with minimal nutrient requirements.

A new variant of was isolated from an anaerobic digester using enrichment cultivation in anaerobic conditions. The new isolate was taxonomically identified via 16S rRNA gene sequencing and tagged as BSEL. The whole genome of the new variant was sequenced and assembled.

Strategies to overcome mass transfer limitations of hydrogen during anaerobic gaseous fermentations: A comprehensive review.

Fermentation of gaseous substrates such as carbon dioxide (CO) has emerged as a sustainable approach for transforming greenhouse gas emissions into renewable fuels and biochemicals. CO fermentations are catalyzed by hydrogenotrophic methanogens and homoacetogens, these anaerobic microorganisms selectively reduce CO using hydrogen (H) as electron donor. However, H possesses low solubility in liquid media leading to slow mass transport, limiting the reaction rates of CO reduction.