Abstract
ON ACCOUNT of incessant human activities, copper is accumulated in the environment at elevated concentrations that induce harmful influences on all kinds of living organisms. An oxic bioreactor was employed to transform copper ions into copper particles using volatile metabolites of Escherichia coli culture. SEM and EDX analysis of the transformed copper showed the formation of elongated particles with 1-5 mu m in length comprising of copper, sulfur, carbon, oxygen and nitrogen elements. Mung bean seeds and barley grains exposed to ionic copper demonstrated low germination and apparent decline of seedlings growth parameters while higher germination and growth rates were recorded with those treated with copper particles. At the same time, an enhanced POD activity was noticed with all Cu treatments, CAT activity seemed to be induced in response to ionic Cu only meanwhile APX activity was markedly affected with both types of Cu. Furthermore, seedlings subjected to Cu particles showed higher protein contents. Toxicity reduction of copper treated with E. coli volatiles was ascribed to the decrease of the mobile copper concentration as a result of interaction with vaporized chelators that reduce bioavailability of copper.