Growth of the acetogenic bacterium Acetobacterium woodii on glycerol and dihydroxyacetone

Abstract

Summary More than 2 million tons of glycerol are produced during industrial processes each year and, therefore, glycerol is an inexpensive feedstock to produce biocommodities by bacterial fermentation. Acetogenic bacteria are interesting production platforms and there have been few reports in the literature on glycerol utilization by this ecophysiologically important group of strictly anaerobic bacteria. Here, we show that the model acetogen Acetobacterium woodii DSM1030 is able to grow on glycerol, but contrary to expectations, only for 2–3 transfers. Transcriptome analysis revealed the expression of the pdu operon encoding a propanediol dehydratase along with genes encoding bacterial microcompartments. Deletion of pduAB led to a stable growth of A. woodii on glycerol, consistent with the hypothesis that the propanediol dehydratase also acts on glycerol leading to a toxic end‐product. Glycerol is oxidized to acetate and the reducing equivalents are reoxidized by reducing CO2 in the Wood–Ljungdahl pathway, leading to an additional acetate. The possible oxidation product of glycerol, dihydroxyacetone (DHA), also served as carbon and energy source for A. woodii and growth was stably maintained on that compound. DHA oxidation was also coupled to CO2 reduction. Based on transcriptome data and enzymatic analysis we present the first metabolic and bioenergetic schemes for glycerol and DHA utilization in A. woodii.

Identification of genes influencing the evolution of Escherichia coli ST372 in dogs and humans

“…This operon was originally described for its involvement in anaerobic microcompartment-mediated metabolism of glycerol and 1,2 propanediol in S. enterica serovar Typhimurium, although it is found in a wide range of enteric and soil-dwelling bacteria [58–62]. In S. enterica, the operon has roles in colonization of the gastrointestinal lumen and in pathogenicity [63–65].…”

“…In the ST372 pan-genome we identified 40 accessory genes that were associated with the largest cluster, cluster M. Among these were genes of the pdu operon. This operon was originally described for its involvement in anaerobic mediated metabolism of glycerol and 1,2 propanediol in S. enterica serovar Typhimurium, although it is found in a wide range of enteric and soil-dwelling bacteria [58][59][60][61][62]. In S. enterica, the operon has roles in colonization of the gastrointestinal lumen and in pathogenicity [63][64][65].…”

A new metabolic trait in an acetogen: Mixed acid fermentation of fructose in a methylene‐tetrahydrofolate reductase mutant of Acetobacterium woodii

“…Alanine was determined enzymatically using alanine dehydrogenase as described previously (Dönig & Müller, 2018). Glycerol and dihydroxyacetone were measured enzymatically (Trifunovic et al, 2021). Caffeate was determined photometrically at 312 nm using an extinction coefficient of 13.72 mM −1 cm −1 (Dilling et al, 2007).…”

“…For transcriptome analyses, the wild-type and the ΔmetVF mutant were grown on 20 mM of fructose and harvested in the exponential growth phase at an OD 600 of 0.2. RNA preparation and RNA sequencing were carried out as described previously (Moon et al, 2021). Subsequently, gene expression levels of the ΔmetVF mutant were compared to those of the wild-type.…”

“…The WLP also enables acetogens to grow on other C1 substrates that are intermediates of the pathway such as formate (Moon et al, 2021), CO (Diekert & Thauer, 1978;Diender et al, 2015;Genthner & Bryant, 1982;Savage et al, 1987;Weghoff & Müller, 2016) or methyl groups (Bache & Pfennig, 1981;Kremp et al, 2018;Kremp & Müller, 2021;Lechtenfeld et al, 2018;Litty et al, 2022;Stupperich & Konle, 1993;van der Meijden et al, 1984).…”