Isolation and characterization of cyanide degrading Bacillus sp. MF3 under alkaline condition

Cyanide is a hazardous compound for all living things. Cyanide compounds are commonly used in various industries and cause environmental pollution. Biodegradation is the best method for cyanide elimination in mines and industrial wastewater. The aims of this study were isolation cyanide degrading bacteria in alkaline condition from contaminated soil and investigation of their ability for cyanide degradation. Contaminated soil samples were enriched in minimal salts medium supplemented with 4.3 mM potassium cyanide. Then cyanide degradation and ammonium production was determined in growth medium using picric acid and Nessler’s regent methods. In addition the ability of the isolated bacterium to utilize different cyanide compounds was investigated. A bacterium with ability to degrade cyanide in alkaline condition was isolated and named MF3. The isolate MF3 degraded cyanide in growth medium under alkaline condition after 36 hours. The results showed that there was a direct relation between decreasing of cyanide concentration, increasing of ammonia concentration and growth of MF3. In addition, the isolated bacterium was demonstrated the ability to utilize different cyanide compounds as a sole carbon and nitrogen source. The 16S rDNA sequencing and phylogenetic analysis was exhibited that MF3 strain was similar to Bacillus safensis with 99% homology. The results of current study were demonstrated that MF3 is a suitable candidate for degradation of cyanide in alkaline condition. This isolate could introduce for elimination of cyanide from industrial wastewater and contaminated sites.