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Attachment stimulates exopolysaccharide synthesis by a bacterium
1College of Marine Studies, University of Delaware, Lewes, Delaware 19958.
Applied and Environmental Microbiology
|October 1, 1993
Summary
Solid surfaces stimulate attached bacteria to produce more exopolymers. This enhanced exopolymer production by surface-attached bacteria was confirmed through microscopy and biochemical analysis.
Area of Science:
- Microbiology
- Biochemistry
Background:
- Bacteria can attach to solid surfaces.
- The production of exopolymers by attached bacteria is not fully understood.
Purpose of the Study:
- To investigate if solid surfaces stimulate exopolymer production in attached bacteria.
- To quantify the difference in exopolymer production between attached and free-living bacteria.
Main Methods:
- Shake-flask cultures with added sand.
- Continuous-flow sand-packed columns.
- Optical microscopy.
- Measurement of total carbohydrates and extracellular polysaccharides.
- Polyanion-binding dye adsorption assays.
Main Results:
- Sand addition induced exopolymer synthesis in subsurface bacterial isolates.
- Attached cells showed significantly higher exopolymer production (2.5-fold total carbohydrates, 5-fold extracellular polysaccharides) compared to free-living cells.
- Exopolymer fraction from attached cells had sixfold greater polyanion-binding dye adsorption.
Conclusions:
- Solid surface attachment stimulates exopolymer synthesis in bacteria.
- This stimulation is independent of growth rate, growth stage, or limiting nutrients.
- Attached bacteria are not a distinct subpopulation of mucoid variants.