Extracellular polymeric substances EPSs

Flemming, H.C. and Wingender, J. (2001) Relevance of microbial extracellular polymeric substances (EPSS) - part 1 Structural and ecological aspects. Water Science and Technology, 43, 1-8. 

Extending this idea one step further, bacteria may have evolved to produce extracellular polymeric substances (EPSs) in order to make mineral surfaces more favorable for attachment. This would be an important evolutionary step, especially if the earliest bacteria utilized minerals for respiration and nutrition.25 According to the present model, oxides other than quartz also have unfavorable entropic interactions with the head group PL (AS°adsi < 0). EPSs should then be exuded on the surfaces of many oxide (and silicate) minerals. As discussed above, quartz is the most harmful, so greater production of EPSs should be expected on quartz, all other factors being equal. Consistent with this hypothesis, the nature of the substrate and of the bacterial surfaces does, in fact, affect the amount of EPS produced.60-62 The idea that surfaces become more hydrophilic by bacterial attachment also underlies the biobeneflciation of ores during mineral separation by floatation. 

Flemming H-C and Wingender J. Relevance of microbial extracellular polymeric substances (EPSs). Part II. Technical aspects. Water Sci Technol. 2001 43(6) 9-16. 

Extracellular polymeric substances are metabolic products. Their production by selected microorganisms was first reported in the 1880s (Whitfield 1988). Extracellular polysaccharides (EPSs) accumulate on the microbial cell surface and provide protection to the cells by stabilizing membrane structure against the harsh external environment. EPSs also serve as carbon and energy reserves. EPSs are a heterogeneous matrix of polymers... 

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