Isolation and characterization of cyanide degrading bacterial strains from contaminated soil

The impact of industrialization on the quality of environment is evident and there is need to have eco-friendly strategies to treat effluent for the sustainable development of industries. Treatment with the help of microorganisms can effectively be used to reduce the load of harmful chemicals in the environment. Study on bioremediation of cyanide released in the effluent has been carried out by the microbes, isolated from soil collected from different industrial contaminated sites. Microbes are enriched in Bushnell-Haas medium containing 100ppm filter sterilized potassium cyanide which has converted it into less toxic products such as ammonia, CO₂, formate and formamide. Three distinct groups of bacteria were isolated which are able to degrade cyanide present in the simulated media. Conditions regarding the pH, maximum concentration of cyanide, dry weight of microbes and presence of ammonia of the simulated effluent were optimized favoring the growth of cyanide degrading bacteria. The optimized conditions can be replicated while utilizing these microbes in the bioremediation studies of cyanide contaminated sites. Morphological, cultural, biochemical and 16S rDNA characterization of isolated bacterial cells has shown that Pseudomonas, Brucella and Ochrobacterum bacterial species are responsible for degrading cyanide.