Bioremediation of Cyanide-Contaminated Soil – An Overview

Abstract

Cyanide contamination in soil, primarily from industrial and mining activities, poses significant environmental and health risks. Microbial bioremediation has emerged as a sustainable and eco-friendly solution, leveraging cyanide-degrading bacteria such as Pseudomonas, Bacillus, Rhodococcus, and Klebsiella to convert toxic cyanide into less harmful compounds like ammonia, formate, and carbon dioxide. Key enzymatic pathways, including cyanidase, nitrilase, and cyanide hydratase, facilitate this degradation. Several strategies enhance bioremediation efficiency include introduces specialized microbial strains to degrade cyanide in soils lacking indigenous degraders. Biostimulation is another process that optimizes environmental conditions (pH, nutrients, aeration) to boost native microbial activity. Microbial consortia also combine complementary metabolic pathways for improved degradation and resilience. Enhancing microbial tolerance and degradation efficiency through synthetic biology tools like CRISPR-Cas9 is known as Genetic engineering. Integrated phytoremediation pairs plants with microbes to stabilize soils and enhance degradation. Immobilization techniques protect microbes using biochar or alginate beads, improving survival in harsh conditions. Despite progress, challenges persist, including microbial sensitivity to high cyanide concentrations, environmental variability, competition with native microbiota, and regulatory concerns over genetically modified organisms (GMOs). This review was aimed to outline the bioremediation strategies of cyanide-contaminated soil. Field-scale applications require adaptive management, real-time monitoring, and interdisciplinary collaboration to ensure long-term success. Future advancements in metagenomics, smart biosensors, and synthetic microbial consortia hold promise for scalable and efficient cyanide bioremediation. By integrating microbial biotechnology with ecological restoration, this approach offers a sustainable pathway for detoxifying contaminated soils while promoting environmental recovery.  

Keywords: Cyanide contamination, microbial bioremediation, cyanide-degrading bacteria, genetic engineering, phytoremediation.