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Project description:Cheap and renewable feedstocks such as the one carbon substrate formate are emerging for sustainable production in a growing chemical industry. By quantitatively analyzing physiology, transcriptome, proteome in chemostat cultivations in combination with computational analyses, we investigated the acetogen Acetobacterium woodii as a potential host for bioproduction from formate alone and together with autotrophic and heterotrophic co-substrates. Continuous cultivations with a specific growth rate of 0.05 h-1 on formate showed high specific substrate uptake rates (47 mmol g‑1 h‑1). Co-utilization of formate with H2, CO, CO2 or fructose was achieved without catabolite repression and with acetate as the sole metabolic product. A transcriptomic comparison of all growth conditions revealed a distinct adaptation of A. woodii to growth on formate as 570 genes were changed in their transcription. Transcriptome and proteome showed higher expression of the Wood-Ljungdahl pathway during growth on formate and gaseous substrates, underlining its function during utilization of one carbon substrates. Flux balance analysis showed varying flux levels for the WLP (0.7-16.4 mmol/g/h) and major differences in redox and energy metabolism. Growth on formate, H2/CO2, and formate+H2/CO2 resulted in low energy availability (0.20-0.22 ATP/acetate) which was increased during co-utilization with CO or fructose (0.31 ATP/acetate for formate+H2/CO/CO2, 0.75 ATP/acetate for formate+fructose). Unitrophic and mixotrophic conversion of all substrates was further characterized by high energetic efficiencies. In silico analysis of bioproduction of ethanol and lactate from formate and autotrophic and heterotrophic co-substrates showed promising energetic efficiencies (70-92%). Collectively, our findings reveal A. woodii as a promising host for flexible and simultaneous bioconversion of multiple substrates, underline the potential of substrate co-utilization to improve the energy availability of acetogens and encourage metabolic engineering of acetogenic bacteria for the efficient synthesis of bulk chemicals and fuels from sustainable one carbon substrates.
2023-03-08 | PXD026569 | Pride
Project description:The bacteria that grow on methane aerobically (methanotrophs) support populations of non-methanotrophs in the natural environment by excreting methane-derived carbon. One group of excreted compounds are short-chain organic acids, generated in highest abundance when cultures are grown under O2-starvation. We examined this O2-starvation condition in the methanotroph Methylomicrobium buryatense 5GB1C . Under prolonged O2-starvation in a closed vial, this methanotroph increases the amount of acetate excreted about 10-fold, but the formate, lactate, and succinate excreted do not respond to this culture condition. In bioreactor cultures, the amount of each excreted product is similar across a range of growth rates and limiting substrates, including O2-limitation. A set of mutants were generated in genes predicted to be involved in generating or regulating excretion of these compounds and tested for growth defects, and changes in excretion products. The phenotypes and associated metabolic flux modeling suggested that in M. buryatense 5GB1C, formate and acetate are excreted in response to redox imbalance, and the resulting metabolic state represents a combination of fermentation and respiration metabolism.
2017-08-24 | GSE101981 | GEO
Project description:Human milk oligosaccharides (HMOs) function as prebiotics for beneficial bacteria in the developing gut, often dominated by Bifidobacterium spp. To understand the relationship between Bifidobacterium utilizing HMOs and how the metabolites that are produced could affect the host, we analyzed the metabolism of HMO 2’-fucosyllactose (2’-FL) in Bifidobacterium longum ssp. infantis Bi-26. RNA-seq and metabolite analysis (NMR/GCMS) was performed on samples at early (A600=0.25), mid-log (0.5-0.7) and late-log phases (1.0-2.0) of growth. Transcriptomic analysis revealed many gene clusters including three novel ABC-type sugar transport clusters to be upregulated in Bi-26 involved in processing of 2’-FL along with metabolism of its monomers glucose, fucose and galactose. Metabolite data confirmed the production of formate, acetate, 1,2-propanediol, lactate and cleaving of fucose from 2’-FL. The formation of acetate, formate, and lactate showed how the cell uses metabolites during fermentation to produce higher levels of ATP (mid-log compared to other stages) or generate cofactors to balance redox. We concluded 2’-FL metabolism is a complex process involving gene clusters throughout the genome producing more metabolites compared to lactose. These results provide valuable insight on the mode-of-action of 2’-FL utilization by Bifidobacterium longum ssp. infantis Bi-26.
2019-04-23 | GSE122350 | GEO
Project description:Hydrogenotrophic methanogenic Archaea are defined by a H2 requirement for growth. Despite this requirement, many hydrogenotrophs are also capable of growth with formate as an electron donor for methanogenesis. Hydrogenotrophs respond to H2 starvation both phenotypically and at the level of gene expression; however, the responses during growth on formate have not been characterized. Here we report that during continuous culture of Methanococcus maripaludis under defined nutrient conditions, growth yields relative to methane production decreased markedly with either H2 excess or formate excess, suggesting that energy spilling occurs. Using microarray analysis, we show that the expression of genes encoding F420-dependent steps of methanogenesis, including one of two formate dehydrogenases, increased with H2 starvation, but with formate occurred at high levels regardless of limitation or excess. One gene, encoding H2-dependent methylene-tetrahydromethanopterin dehydrogenase, decreased in expression with either H2 limitation or formate limitation. Expression of genes for the second formate dehydrogenase, molybdenum-dependent formylmethanofuran dehydrogenase, and molybdenum transport increased specifically with formate limitation. Of the two formate dehydrogenases, only the first could support growth on formate in batch culture where formate was in excess.
2013-05-03 | GSE42111 | GEO
Project description:Recently identified spontaneous mutants of major glucose-PTS (manLMNO) in stocks of Streptococcus sanguinis SK36 showed enhanced fitness in low-pH environment. Transcriptomic and metabolomic analyses of the manL mutant (SK36/manL) revealed redirection of pyruvate from production of lactate to acetate for extra energy extraction, resulting in excretion of greater amounts of pyruvate and H2O2, and increased expression of multiple alkali-generating activities. Genes showing increased expression in SK36/manL also included several carbohydrate transporters, putative extracellular glycosidases, intracellular polysaccharide (IPS) locus, pathways for catabolism of acetoin, ethanolamine, ascorbate, and formate, genes required for membrane biosynthesis, and those for motility and attachment.
2022-07-28 | GSE209672 | GEO
Project description:Little is known about the bacteria that reside in human gallbladder and the mechanisms that allow them to survive within this harsh environmental niche. Furthermore, certain bacterial species are considered to exhibit antagonistic activities whilst others may form mutualistic interactions through, for example, cross-feeding. We isolated two new strains from healthy human bile samples, one belonging to Ruminococcus gauvreauii, of Lachnospiraceae family, and other constituting a new specie in Ruminococcaceae family, named Ruminocoides biliarensis. The two strains differed markedly in their carbohydrate metabolism as R. gauvreauii mainly metabolised sugar alcohols, including inositol, to form acetate as unique fermentation product, and Rc. biliarensis mainly metabolised resistant starches to mainly form formate and acetate as fermentation end products. Both strains exhibited resistance to different bile salts, and the ability to sporulate. Amino acid and vitamin biosynthesis profiles also markedly differed between the two bile isolates. Finally,RNAseq was used to analyse the co-cultures of both isolates, to analyze the activities involved in the possible cross-feeding relationship.
2022-07-05 | GSE140753 | GEO
Project description:In this work, we investigated intracellular pH homeostasis within the thermoacidophilc methanotroph Methylacidiphilum sp. RTK17.1. Our findings show the proton motive force for this species is primarily generated by a pH gradient across the cellular membrane. In batch experiments, the addition of formate resulted in no observable cell growth and, correspondingly, acidification of the cytosol, decreased formate dehydrogenase activity and (presumably) cell-death. Nevertheless, we were able to demonstrable growth on formate as the sole source of metabolizable energy was possible in steady-state (continuous) cultures following the transition from methanol to formate. Under these conditions, biomass productivity yields on formate were 63% less than for growth on methanol. Transcriptome analysis revealed key genes associated with pH homeostasis, methane, methanol and formate metabolism were significantly regulated in response to growth on formate. Collectively, these results suggest environmental formate represents a utilisable source of energy/carbon to the acidophilic methanotrophs during periods of methane starvations and highlights potential short-comings of traditional batch-culture physiological characterisation studies in acidophilic species.
2020-10-31 | GSE145277 | GEO
Project description:Aliquots of Jurkat T-lymphocyte cells were washed with 5 different rinsing solutions (0.3% amm. formate, 0.3% amm. acetate, 0.9% NaCl, 1 M PBS, 100 mM PBS) and ran in triplicate to monitor the effect of ion suppression on the electrospray ionization signal.
2015-03-02 | ST000140 | MetabolomicsWorkbench
Project description:The mitochondrial serine catabolism to formate induces a metabolic switch to a hypermetabolic state with high rates of glycolysis, purine synthesis and pyrimidine synthesis. While formate is a purine precursor it is not obvious link between formate and pyrimidine synthesis. Methods Here we combine phospho-proteome and metabolic profiling to determine how formate induces pyrimidine synthesis. We discover that formate induces CAD phosphorylation. Mechanistically formate induces mTORC1 activity as quantified by S6K1 phosphorylation, which is known to phosphorylate CAD and increase its enzymatic activity. Treatment with the allosteric mTORC1 inhibitor rapamycin abrogates CAD phosphorylation and pyrimidine synthesis induced by formate. We conclude that formate activates mTORC1 and induces pyrimidine synthesis via increasing CAD activity.
2020-09-28 | PXD019347 | Pride
Project description:The introduction of alternative CO2-fixing pathways such as formate synthesis and assimilation may improve the efficiency of biological carbon fixation that appears to be limited by the enzymatic properties of ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO). Here we aimed to establish a formate assimilation pathway in the model cyanobacterium Synechocystis sp. PCC 6803. The formate-tetrahydrofolate ligase (FTL) from Methylobacterium extorquens AM1 was expressed in Synechocystis to enable formate assimilation and reduce the loss of fixed carbon in the photorespiratory pathway. Transgenic strains accumulated serine and 3-phosphoglycerate, and consumed more 2-phosphoglycolate and glycine, which seemed to reflect the efficient utilization of formate. However, labelling experiments showed that the serine accumulation was not due to the expected incorporation of formate. DNA-microarray experiments were performed to analyze possible transcriptome changes due to ftl expression. Marked changes in expression of genes encoding proteins associated with serine biosynthesis and enzymes involved in nitrogen and C1 metabolism revealed that ftl expression had a regulatory impact on these metabolic routes. Our results indicate that the expression of new pathways could have a severe impact on the cellular regulatory network, which hampers the establishment of newly designed pathways.
2020-01-17 | GSE143785 | GEO