Enhanced Biomass Production of Rhodococcus UKMP-5M as Potential Biological Tool for Cyanide Bioremediation

Despite its toxicity, cyanide has been utilized in many industrial processes leading to the generation of voluminous effluents which necessitated treatment prior to discharge into the environment. However, the existing physical and chemical methods for cyanide-containing wastewater removal are incompetent due to reasons such as cost, generation of secondary pollutants and ineffective decontamination of cyanide complexes. Therefore, the development of biological method which can support complete detoxification at low costs is desired for treatment of cyanide-containing wastewater. Rhodococcus UKMP-5M exhibited the potential to detoxify cyanide due the presence of nitrile (organic cyanide) catabolism in its genome sequence. Supplementing the medium with glucose and L-proline at 2 % (v/v) inoculum resulted in enhanced biomass production of Rhodococcus UKMP-5M by 93 % in comparison to sole nutrient broth medium. In addition, the optimized culture conditions at temperature 30 °C and pH value of 6.6 yielded maximized production of biomass for the detoxification cyanide. These findings are highly significant since they accommodated the tropical temperature of Malaysia and the alkaline nature of cyanide-containing wastewater which should be of great interest from an environmental and economic point of views.