In vitro cyanide degradation by Serretia marcescens RL2b

Detoxification of cyanide compounds using biological systems is gaining much attention due to various advantages over the traditional physical and chemical methods. In present study, a cyanide degrading bacterial strain RL2b was isolated from forest soil of Himachal Pradesh. Based on the morphology, physiological, biochemical tests and its 16S rDNA sequence, the bacterial isolate RL2b was identified as Serretia marcescens. In vitro degradation of cyanide by this organism was investigated by varying several cultural conditions viz. medium, carbon and nitrogen sources, pH and temperature. Serretia marcescens RL2b exhibited maximum cyanide degradation in medium M1 containing glycerol and tryptone as carbon and nitrogen source respectively. Cyanide degradation was maximum at pH 6.0 and 35°C temperature. This bacterial isolate exhibited cyanide tolerance up to 16 mM and highest cyanide degradation at 12 mM in 40 h. The present study revealed that the strain Serretia marcescens RL2b has high cyanide tolerance and degradation potential at wide pH and temperature range and thus has very good potential for efficient cyanide removal from environment.