Degradative bacterial colonies

Figure 3. Autoradiographic detection of naphthalene degradative bacterial colonies from MGP soil enrichments used as inoculum for continuous stirred soil slurry bioreactors.

Pettigrew, C. A. Sayler, G. S. (1986). The use of DNA DNA colony hybridization in the rapid isolation of 4-chlorobiphenyl degradative bacterial phenotypes. Journal of Microbiological Methods, 5, 205-13. 

Of the more than 200 bacterial colonies isolated from an atrazine-mineralizing mixed culture, none were found to individually degrade atrazine however, when mixed together, their degradation ability was restored (Mandelbaum etal., 1993a). 

In the former case, a bacterial or fungal colony on the surface of the material releases an extracellular degrading enzyme which breaks down the polymer chains into smaller units (dimers and ohgomers), which then are absorbed through the microorganisms ceU membrane and metabolised as a source of nutrient (carbon). It has been proposed that this mechanism first hydrolyses the chains of the amorphous phase of poly-(3-hydroxybutyrate) (PHB) and then proceeds to attack the chains in the crystalline state. The enzymatic degradation rate decreases as the crystallinity increases [15, 16]. 

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