Diverse polysaccharide macromolecules are synthesized by bacteria using a rich arsenal of distinct pathways and function as cell wall components or storage units, to counteract harsh environmental conditions, as masking agents, or as part of the matrix by which bacterial cells reside in sessile life style. Over the past few years, it has become clear that there are unifying themes in bacterial polysaccharide synthesis, regulation, and function.

Unlike other microbiological traits, bacterial polysaccharides link primary metabolism with extracellular function, thus acting at the interface between bacterium and host, and therefore biosynthesis needs to be tightly controlled at the level of transcription due to their high demand for cellular energy. Bacterial cells 'invest' in polysaccharide synthesis without immediately 'knowing' the beneficial outcome of this synthesis since many of those macromolecules are simply secreted or produced outside of the cell. Consequently, understanding the regulatory links between intracellular energy conservation, polymer synthesis and modification, and the external ecological functions becomes increasingly important for us to better benefit from or to more efficiently combat biological effects mediated by bacterial polysaccharides.

It has been fully appreciated for quite some time that a sessile life is presumably the dominant way of bacteria thriving - be it on a surface, such as our teeth, or the pipelines in biotechnology - within various organs and tissues of eukaryotic hosts, inside dirt, or on any marine aggregate floating in the oceans. At the same time it has become clear that not only exopolysaccharides but also the non-watery composite of biofilm matrices is of tremendously diverse origin. Consequently, researchers are beginning to understand that polysaccharides might be - at least in part - waste disposal storage sites for later recycling, which evolutionarily have become powerful tools, connectors, or barriers for microbe–microbe and microbe–host interactions.

from Matthias Ullrich in Bacterial Polysaccharides

Further reading: Bacterial Polysaccharides: Current Innovations and Future Trends

Labels: bacterial polysaccharides, EPS, exopolysaccharides

Microorganisms synthesize a wide spectrum of exopolysaccharides many of which have important applications in biotechnology and the food imdustry. Exopolysaccharides produced by microorganisms include:

acetan (Acetobacter xylinum)

alginate (Azotobacter vinelandii)

cellulose (Acetobacter xylinum)

chitosan (Mucorales spp.)

curdlan (Alcaligenes faecalis var. myxogenes)

cyclosophorans (Agrobacterium spp., Rhizobium spp. and Xanthomonas spp.)

dextran (Leuconostoc mesenteroides, Leuconostoc dextranicum and Lactobacillus hilgardii)

emulsan (Acinetobacter calcoaceticus)

galactoglucopolysaccharides (Achromobacter spp., Agrobacterium radiobacter, Pseudomonas marginalis, Rhizobium spp. and Zooglea spp.)

gellan (Aureomonas elodea and Sphingomonas paucimobilis)

glucuronan (Rhizobium meliloti)

N-acetyl-heparosan (Escherichia coli)

hyaluronic acid (Streptococcus equi)

indican (Beijerinckia indica)

kefiran (Lactobacillus hilgardii)

lentinan (Lentinus elodes)

Levan polysaccharide|levan (Alcaligenes viscosus, Zymomonas mobilis)

pullulan (Aureobasidium pullulans)

scleroglucan (Sclerotium rolfsii, Sclerotium delfinii and Sclerotium glucanicum)

schizophyllan (Schizophylum commune)

succinoglycan (Alcaligenes faecalis var myxogenes)

xanthan (Xanthomonas campestris)

welan (Alcaligenes spp.)

Anita Suresh Kumar and Kalpana Mody from Chapter 10 in Microbial Production of Biopolymers and Polymer Precursors

Further reading: Microbial Production of Biopolymers and Polymer Precursors

Labels: bacterium, exopolysaccharides, lactic acid bacteria