Abstract
Agricultural and industrial activities contribute most to pollutants found globally, and bioremediation of these pollutants is being intensely sought. We have isolated a molybdenum-reducing bacterium from agricultural soil for bioremediation purposes. The bacterium was grown in low phosphate medium supplemented with molybdate in a microplate format. The molybdenum-reducing bacterium was then further screened for amide-degrading properties. The bacterium was able to use acrylamide as a source of electron donor for reduction, and was able to grow' on acrylamide, acetamide and acetonitrile. The growth parameters obtained according to the modified Gompertz model were lag periods of 0.468, 0.979 and 1.53 d and maximum specific growth rates of 1.165,0.932,0.842 d(-1) for acrylamide, acetamide and acetonitrile respectively. Optimal conditions tor molybdate reduction included glucose, pH between 6.0 and 6.8, temperature between 25 degrees C and 34 degrees C, and phosphate and molybdate concentrations between 5 and 7.5 mM and 10 and 20 mM, respectively. The Mo-blue exhibited a unique absorption spectrum closely resembling a reduced phosphomolybdate. Mo-blue production was inhibited by the heavy metals copper, mercury, silver, chromium and cadmium. The bacterium was identified as Bacillus sp. strain Zeid 14. The bacterium will be very useful for bioremediation of sites contaminated with molybdenum and amides.