Index >> Fundamentals of Microbial Ecology >> Attachment Properties of Microbes

Extracellular enzymes may be adsorbed onto the microbial surface. The fact that microbe is attached to something larger may prevent it from being eaten by predators or from being dessicated. Viruses and bacteriophages may survive longer in natural environment if they are adsorbed than when they are free.

Process of attachment The process of attachment takes place in two stages:
Adsorption This is physical or chemical and not controlled by the organisms.

Adhesion Organisms secrete a protein or a glycoprotein glue which attracts similar species to each other forming a colony. This colonisation depends on the environmental factors controlling growth.

This distance is greatly reduced (0.5 nm) in concentrated solutions of polyvalent ions. Any surface coating, whether adsorbed or produced by the microorganisms will have a great effect on the surface chemistry.

Hence, at a given ionic strength, the repulsion between the bacterium and a surface bearing a like charge is directly proportional to the reciprocal of the squares of distance between them.

The balance between the van der Waal’s forces of attraction and the electrostatic repulsion determines whether the bacterium is attracted to the surface or repelled from it.