Evaluation of the Potential of Immobilized Cyanide-Degrading Bacteria for the Bioremediation of Cassava Mill Effluent

This study aimed to assess the feasibility of employing indigenous cyanide-degrading bacterial strains for the treatment of cassava mill effluent (CME) in Nigeria, a hazardous waste material posing significant public health risks.The physicochemical properties and heavy metal concentrations in CME were determined through standard methodologies.Cyanide-degrading bacteria were isolated, characterized, and identified using molecular techniques.These strains were immobilized within a porous network of cross-linked biochar, confirmed through SEM imaging, and evaluated alongside free cells for CME bioremediation.Multiple variables were examined to assess the effluent's pollution load, including pH, electrical conductivity (EC), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total dissolved solids (TDS), nitrate (NO3), phosphate (PO4), and cyanide levels, falling within respective ranges of (4.00-4.02),(2394-2618 S/cm), (985-1219 mg/L), (1556-1667 mg/L), (3459-3705 mg/L), (2709-2812 mg/L), (251-311 mg/L), (87.25-118 mg/L), and (25.00-28 mg/L).Copper was the most prevalent heavy metal in the effluent, while chromium was detected at the lowest levels, with mean values of 10.00-12.39mg/L and 0.00-0.27mg/L, respectively.The study revealed severe contamination of the effluent, above the Federal Environmental Protection Agency (FEPA) threshold limit.The 16S rDNA of the cyanide degrading bacteria were deposited at the NCBI database and the following GenBank accession numbers were assigned (MK71248O, MK71281, MK712482, and MK712483) for Pseudomonas putida, Bacillus subtilis, Alcaligenes faecalis and Leuconostoc mesenteroides respectively.Results of the bioremediation approach demonstrated a substantial reduction in physicochemical parameters and heavy metal contents, indicating a promising biological treatment strategy to mitigate CME's adverse effects on public health.In conclusion, despite elevated physicochemical parameters and heavy metal concentrations in CME, this study offers a promising avenue for employing biological treatments to mitigate environmental and public health impacts.Further research and application of this technique hold substantial potential for cassava mill effluent management in Nigeria and other regions facing similar challenges.