Immobilised bacteria

Both techniques are more or less still under investigation in preliminary applications. However, they may be an interesting alternative in the future, if executed with immobilised bacteria, because complete removal of potentially detrimental bacteria by cleaning methods after the treatment is difficult to achieve. Even if biocides were applied for disinfestation purposes, the cell material (biomass) would stay on the surface and in the material pores and provide a nutrient supply for other microorganisms. 

Tsygankov, A.A., Fedorov, A.S., Talipova, I.V., Laurinavichene, T.V., Miyake, J., Gogotov, I.N. (1998a). Application of immobilised phototrophic bacteria for waste water purification and hydrogen production. Appl. Biochem. Microbiol. 34,362-366. 

A Pz immunosensor for the detection of Listeria monocytogenes was published by Jacobs et al. [87]. The bacteria could be measured to 10 cellsmL using dip and dry methods of detection. Analysis carried out directly in solution allowed detection to 5 x 10 cells mL. Antibody coated crystals were stored for 17 days without detectable loss in activity. Protein A was used as the immobilisation method but not compared to others. Later the group published details of a displacement assay for the detection of this species [88]. This assay could detect the antigen from 2.5 x 10 to 2.5 x 10 cells/crystal directly in solution monitoring the response in real time. The assay was also performed in milk. Assays in milk were also shown to be specific for... 

KOnig and Gratzel published details of a sensor for the detection of diarrhoea-causing bacteria and viruses [9]. Immunosensors were described for the detection of rotavirus and adenovirus. Both viruses were measured linearly from lO to 10 ° virions. As explained earher, protein A was shown to be the most favourable immobilisation method but immobilisation using silane and polyethyleneimine showed a 40% increase in response when detecting rotavirus in stool samples. 

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