Cyanide degradation by immobilized cells of Rhodococcus UKMP-5M

Abstract

Anthropogenic sources contribute to the bulk presence of cyanide, which causes substantial health and environmental concerns. A petroleum-contaminated soil isolate, Rhodococcus UKMP-5M has been verified to efficiently degrade high concentration of cyanide in the form of KCN in our previous study. In order to enhance the cyanide-degrading ability of this bacterium, different encapsulation matrices were screened to immobilize cells of Rhodococcus UKMP-5M for degradation of cyanide. It was revealed that the biocatalyst activity and bead mechanical strength improved significantly when calcium alginate encapsulation technique was employed as compared to free cells. The results also indicated that the immobilized cell system could tolerate a higher level of KCN concentration and were able to support a higher biomass density. In addition, the embedded cells retained almost 96% of their initial cyanide removal efficiency during the first five batches and the entrapped cell system maintained 64% of its initial activity after eight successive batches. The encapsulated beads could be easily recovered from the production medium and reused for up to five batches without significant losses of cyanide-degrading ability, which proved to be advantageous from an economic point of view. From this study, it could be inferred that the novel Rhodococcus UKMP-5M strain demonstrated high cyanide-degrading ability and the optimized calcium alginate immobilization technique provided a promising alternative for practical application of large scale remediation of cyanide-bearing wastewaters.

Biodegradation of cyanide by acetonitrile-induced cells of Rhodococcus sp. UKMP-5M

“…Rhodococcus sp. UKMP-5M, a bacterial strain isolated from petroleum-contaminated soils, demonstrated promising potential in cyanide degradation as reported earlier (Nallapan Maniyam et al, 2011, 2012. The present work aims to further characterize the cyanide-degrading ability of growing cells of Rhodococcus sp.…”

Cyanide Bioremediation by Bacillus subtilis under Alkaline Conditions

“…They can degrade high cyanide concentrations, operate over a range of pH levels and temperatures, and require simple nutritional inputs [30]. Applications as suspended cultures or immobilized cells enhance the stability and cyanide degradation capacity [41]. Additionally, engineered and alkaliphilic bacterial strains can be designed for optimized biodegradation under specific conditions [42].…”