“Candidatus Galacturonibacter soehngenii” Shows Acetogenic Catabolism of Galacturonic Acid but Lacks a Canonical Carbon Monoxide Dehydrogenase/Acetyl-CoA Synthase Complex

Acetogens have the ability to fixate carbon during fermentation by employing the Wood-Ljungdahl pathway (WLP), which is highly conserved across Bacteria and Archaea. In a previous study, product stoichometries in galacturonate-limited, anaerobic enrichment cultures of “Candidatus Galacturonibacter soehngenii,” from a novel genus within the...

A Novel D-Galacturonate Fermentation Pathway in Lactobacillus suebicus Links Initial Reactions of the Galacturonate-Isomerase Route With the Phosphoketolase Pathway

D-galacturonate, a key constituent of pectin, is a ubiquitous monomer in plant biomass. Anaerobic, fermentative conversion of D-galacturonate is therefore relevant in natural environments as well as in microbial processes for microbial conversion of pectin-containing agricultural residues. In currently known microorganisms that anaerobically...

Selecting for lactic acid producing and utilising bacteria in anaerobic enrichment cultures

Lactic acid-producing bacteria are important in many fermentations, such as the production of biobased plastics. Insight in the competitive advantage of lactic acid bacteria over other fermentative bacteria in a mixed culture enables ecology-based process design and can aid the development of sustainable and energy-efficient bioprocesses....

O₂ versus N₂O respiration in a continuous microbial enrichment

Despite its ecological importance, essential aspects of microbial N₂O reduction—such as the effect of O₂ availability on the N₂O sink capacity of a community—remain unclear. We studied N₂O vs. aerobic respiration in a chemostat culture to explore (i) the extent to which simultaneous respiration of N...

Role of nitrite in the competition between denitrification and DNRA in a chemostat enrichment culture

Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two microbial processes that compete for oxidized nitrogen compounds in the environment. The objective of this work was to determine the role of nitrite versus nitrate as terminal electron acceptor on the competition between DNRA and denitrification. Initially, a mixed...

Combining the enrichment and accumulation step in non-axenic PHA production: Cultivation of Plasticicumulans acidivorans at high volume exchange ratios

The process for non-axenic polyhydroxyalkanoate (PHA) production from organic waste generally comprises three steps: acidogenic fermentation of the waste stream, enrichment of a PHA-producing culture, and production of the PHA. This study assesses the feasibility of combining the enrichment and production step. Harvesting PHA-rich biomass...