Sugar uptake by the solventogenic clostridia

Mitchell, Wilfrid J.

doi:10.1007/s11274-015-1981-4

Cited by 31 publications

(24 citation statements)

References 78 publications

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“…The use of ABC transporters for hexose transport by C. phytofermentans differs from that of E. coli, Bacillus subtilis, and solventogenic Clostridia, such as C. acetobutylicum and C. beijerinckii, which all use PTS as the primary mechanism of hexose uptake (26).…”

Section: Discussionmentioning

confidence: 99%

ABC Transporters Required for Hexose Uptake by Clostridium phytofermentans

et al. 2019

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The mechanisms by which bacteria uptake solutes across the cell membrane broadly impact their cellular energetics. Here, we use functional genomic, genetic, and biophysical approaches to reveal how Clostridium (Lachnoclostridium) phytofermentans, a model bacterium that ferments lignocellulosic biomass, uptakes plant hexoses using highly specific, nonredundant ATP-binding cassette (ABC) transporters. We analyze the transcription patterns of its 173 annotated sugar transporter genes to find those upregulated on specific carbon sources. Inactivation of these genes reveals that individual ABC transporters are required for uptake of hexoses and hexo-oligosaccharides and that distinct ABC transporters are used for oligosaccharides versus their constituent monomers. The thermodynamics of sugar binding shows that substrate specificity of these transporters is encoded by the extracellular solute-binding subunit. As sugars are not phosphorylated during ABC transport, we identify intracellular hexokinases based on in vitro activities. These mechanisms used by Clostridia to uptake plant hexoses are key to understanding soil and intestinal microbiomes and to engineer strains for industrial transformation of lignocellulose. IMPORTANCE Plant-fermenting Clostridia are anaerobic bacteria that recycle plant matter in soil and promote human health by fermenting dietary fiber in the intestine. Clostridia degrade plant biomass using extracellular enzymes and then uptake the liberated sugars for fermentation. The main sugars in plant biomass are hexoses, and here, we identify how hexoses are taken in to the cell by the model organism Clostridium phytofermentans. We show that this bacterium uptakes hexoses using a set of highly specific, nonredundant ABC transporters. Once in the cell, the hexoses are phosphorylated by intracellular hexokinases. This study provides insight into the functioning of abundant members of soil and intestinal microbiomes and identifies gene targets to engineer strains for industrial lignocellulosic fermentation.

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Section: Discussionmentioning

confidence: 99%

ABC Transporters Required for Hexose Uptake by Clostridium phytofermentans

et al. 2019

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“…In clostridia, like other bacteria, sugars may be transported into the cell via the phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS), which both transports and phosphorylates the substrate [21–23]. Based on the structural similarities to enzymes of the PTS IIBC subunit sugar transport genes, a putative gene for transport and metabolism of trehalose via the PTS has been identified in C. perfringens [2, 24].…”

Section: Introductionmentioning

confidence: 99%

Effect of Trehalose and Trehalose Transport on the Tolerance ofClostridium perfringensto Environmental Stress in a Wild Type Strain and Its Fluoroquinolone-Resistant Mutant

Park

Mitchell

Rafii

2016

International Journal of Microbiology

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Trehalose has been shown to protect bacterial cells from environmental stress. Its uptake and osmoprotective effect in Clostridium perfringens were investigated by comparing wild type C. perfringens ATCC 13124 with a fluoroquinolone- (gatifloxacin-) resistant mutant. In a chemically defined medium, trehalose and sucrose supported the growth of the wild type but not that of the mutant. Microarray data and qRT-PCR showed that putative genes for the phosphorylation and transport of sucrose and trehalose (via phosphoenolpyruvate-dependent phosphotransferase systems, PTS) and some regulatory genes were downregulated in the mutant. The wild type had greater tolerance than the mutant to salts and low pH; trehalose and sucrose further enhanced the osmotolerance of the wild type to NaCl. Expression of the trehalose-specific PTS was lower in the fluoroquinolone-resistant mutant. Protection of C. perfringens from environmental stress could therefore be correlated with the ability to take up trehalose.

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“…The major mechanism of sugar uptake is the PEP-dependent phosphotransferase system (PTS), which both transports and phosphorylates its sugar substrates and plays a central role in metabolic regulation. Clostridial genome sequences have indicated the presence of numerous phosphotransferase systems for uptake of hexose sugars, hexose derivatives and disaccharides, confirming its versatility to use a range of substrates (Mitchell, 2016).…”

Section: Better Understanding Of Clostridial Metabolismmentioning

confidence: 96%

An integrated approach: advances in the use ofClostridiumfor biofuel

Kök

2015

Biotechnology and Genetic Engineering Reviews

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Almost 90% of our energy comes from fossil fuels, which are both limited and polluting, hence the need to find alternative sources. Biofuels can provide a sustainable and renewable source of energy for the future. Recent significant advances in genetic engineering and fermentation technology have made microbial bio-based production of chemicals from renewable resources more viable. Clostridium species are considered as promising micro-organisms for the production of a wide range of chemicals for industrial use. However, a number of scientific challenges still need to be overcome to facilitate an economically viable production system. These include the use of cheap non-food-based substrates, a better understanding of the metabolic processes involved, improvement of strains through genetic engineering and innovation in process technology. This paper reviews recent developments in these areas, advancing the use of Clostridium within an industrial context especially for the production of biofuels.

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Sugar uptake by the solventogenic clostridia

Cited by 31 publications

References 78 publications

ABC Transporters Required for Hexose Uptake by Clostridium phytofermentans

ABC Transporters Required for Hexose Uptake by Clostridium phytofermentans

Effect of Trehalose and Trehalose Transport on the Tolerance ofClostridium perfringensto Environmental Stress in a Wild Type Strain and Its Fluoroquinolone-Resistant Mutant

An integrated approach: advances in the use ofClostridiumfor biofuel

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