Bacterial enzyme biosyntheses inhibition; a tool for ecotoxicity assay

Abstract

The inhibition of biosyntheses of four bacterial enzyme systems by 39 chemicals (hydrocarbon fuels, oil spill dispersants, household detergents, drilling chemicals and crude oils) were examined as a tool for ecotoxicity assay. The enzyme systems were two extracellular inducible enzymes tryptophanase and ß - glucosidase produced by Escherichia coli and Bacillus licheniformis respectively, one intracellular inducible enzyme ß - galactosidase in E. coli and the constitutive enzymes in Nitrobacter mediating the oxidation of nitrite to nitrate “nitritase”. Ecotoxicity assay results were obtained within 5 hours after commencement of tests. Beta –galactosidase biosynthesis was the most insensitive to the 39 chemicals. Tryptophanase and α-glucosidase biosyntheses displayed similar but higher levels of sensitivities to the chemicals. “Nitritase” enzymes biosynthesis was the most sensitive to all the toxicants. The inhibition of constitutive enzyme systems such as the “nitritase” enzyme system may thus be considered as a tool for rapid ecotoxicity assays.


Key words: Constitutive, Inducible, Ecotoxicity, Extracellular Intracellular.


(Global Journal of Pure and Applied Sciences: 2003 9(4): 445-452)