CYANOBACTERIA MUTANTS WITH INCREASED SENSITIVITY TO HERBICIDES - AN IMPROVED BIOLOGICAL-MATERIAL FOR BIOSENSORS

A biosensor for the detection of herbicides in water is described, which incorporates a cyanobacteria, Synechococcus sp., as integrated biological component. Herbicides bind at the photosynthetic membranes of these bacteria and hence block the electron transport system. This leads to a decrease in oxygen production and an inhibition of growth. The present sensitivity of the biosensor is not sufficient to satisfy the regulations governing drinking water quality control. Hence the aim of the project was to isolate mutants, that has an improved sensitivity to herbicides relative to the wildtype. Through the induced mutagenesis (by UV-irradiation, 1-methyl-3-nitro-1-nitrosoguanidine) a mutant could be isolated, with a higher sensitivity towards herbicides. The higher sensitivity of the mutant was improved by an inhibition test in liquid culture and a measurement of oxygen production rate.