Effects of heavy metals and selected carbon compounds on the growth of bacterium CA

Abstract

Nowadays environment has been suffering from the contamination by heavy metals and organic compounds. Modernization, urbanization and industrialization further increase the levels of contamination. In this work, the ability of bacterium CA previously isolated from textile waste water was investigated to tolerate to aluminium, copper, cobalt, zinc and manganese at different concentrations. The MIC were found to be 400, 200, 40, 60, 300 mg/L, respectively, the growth rate at MIC were 0.1732, 0.417, 0.0885, 0.2824 and 0.4046 h-1, respectively, and the doubling time values at MIC were 4.005, 1.66187, 7.83, 2.4539 and 1.7128 h-1, respectively. Different organic compounds were supplied as sole carbon sources at chemically defined media. The bacterium CA could grow on the CDM provided with casamino acids, casamino acids (as both carbon and nitrogen source), glucose and glycerol with growth rate of 0.0297, 0.0317, 0.04 and 0.0492 h-1, respectively. Whereas the bacterium failed to grow when sulfanilic acids, acrylamide and benzene were only source of carbon. Bacterium CA was found to be sensitive to tetracycline hydrochloride and kanamycin sulfate with clear zones of 2.8 and 2.6 cm, respectively, while it was resistant to XY-12 and ampicillin trihydrate. Moreover, bacterium CA was found to be closest with Bacillus thuringiensis with accession number NR_102506 via 16S rRNA gene analysis. In conclusion, bacterium CA was positive to tolerate to heavy metals, results were significant in case of aluminium, manganese and copper. Bacterium CA was able to grow on different organic compounds that indicated the presence of different mechanisms of carbon source up take and metabolism in the bacterium system. The obtained results suggested the bacterium CA could be potentially used for the treatment of wastewater contamination containing heavy metals and organic compounds.