Bacterial biofilms are formed when bacteria in a liquid environment adhere to a surface, multiply to form microcolonies and synthesis a protective glycocalyx composed mainly of hydrated exopolysaccharide (EPS). Bacterial biofilms form in natural, medical and industrial environments and are usually highly heterogeneous. Biofilms can be single or multi-species and their characteristics are dictated by the environment in which they develop. The biofilm bacteria analysed were isolated from a factory environment and all were members of the Enterobacteriaceae. The composition of their extracellular polysaccharides was examined using standard biochemical assays, HPLC and paper chromatography. Most were anionic due to uronic acids, except for the EPS of two strains, 53b and Ent (both <I>Enterobacter agglomerans</I>), which contained only neutral sugars and were highly insoluble. Periodate oxidation revealed a high degree of 1→3 linkages. Bacteriophages which possessed polysaccharide depolymerase enzymes specific for the EPS of strains 53b and Ent were isolated from sewage from a number of sources. The glycanase of one phage (SF153b) was highly specific, had optima over a wide range of temperature and pH, and activity was increased by Ca<SUP>2+</SUP> ions. Degradation of 53b and Ent EPS by the depolymerase produced oligosaccharide repeat units. HPLC and size exclusion chromatography gave an estimation of DP for 53b and Ent repeat units of 8-9 and 7-8 respectively. Polysaccharide samples derived from 53b biofilm and planktonic cells were both degraded by the same phage glycanase suggesting that biofilm formation does not stimulate production of a biofilm specific EPS.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:652686 |
| Date | January 1997 |
| Creators | Hughes, Kevin A. |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/15053 |
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