Biofilm slime penetrants

Of considerable significance is that most individual biocides are not equally and simultaneously effective as biofilm slime penetrants and removers, algaecides, and bactericides (yet algae can act as a feed source for bacteria, necessitating control over both types of organism). 

Gluteraldehyde + 10% block copolymer (BCP), a nonionic biodispersant. Dose at 40 to 50 ppm. Effective as a slime penetrant, sessile bacteria biocide, and biofilm remover. Not particularly suitable with high levels of ammonia or primary amine. 

In order to understand current approaches for prevention and control of biofilms, we must first consider the reasons for the failure of conventional antimicrobial protocols. There are thought to be three main reasons as to why biofilm bacteria out-survive their planktonic counterparts during antimicrobial treatments (reviewed by McBain et a/.16).These are i) poor penetration of antimicrobial compounds due to the presence and turn-over of exopolymer slime (glycocalyx) ii) the imposition of extreme nutrient limitation within the depths of the biofilm community and the co-incident expression of metabolically-dormant, recalcitrant phenotypes and (iii) the expression of attachment-specific phenotypes that are radically different and intrinsically less susceptible than unattached ones. 

A description of any type of bacteria found attached or bound-up in slimes or biofilm. Potentially more of a problem than planktonic bacteria due to the difficulty of biocides penetrating the slime and the potential for rapid system re-infection. 

The ability of the stone-colonizing microflora to cover and even penetrate material surface layers by the excretion of organic extracellular polymeric substances (EPS) leads to the formation of complex slimes, or biofilms, in which the microbial cells are embedded. Phototrophic organisms usually initiate colonisation by establishing a visible, nutrient-rich biofilm on new stone from which they can penetrate the material below to seek protection from high light intensities or desiccation. Stone EPS trap aerosols, dust and nutrients, minerals,... 

Knowledge of the composition of shme deposits and the formation mechanisms of biofilms has led to more selective slime control agents, in combination with the use of chemicals that are capable of either penetrating the biofihns or dispersing the deposits. So less toxic substances can be used in the system and keeping machine surfaces is easier. 

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