Biodegradation of cyanide in cassava wastewater using a novel thermodynamically-stable immobilized rhodanese.

Extracellular rhodanese obtained from was employed in both free and immobilized forms for the biodegradation of cyanide present in cassava processing mill effluent (). Crosslinking with glutaraldehyde (at an optimum concentration of 5% v/v) before entrapment in alginate beads resulted in the highest immobilization yield of 94.5% and reduced enzyme leakage of 1.8%. Rhodanese immobilized by cross-linking before entrapment ( retained about 46% of its initial activity after eight cycles of catalysis compared to the entrapment in alginate alone () which lost more than 79% after the fifth catalytic cycle. A cross-examination of thermodynamic ( ) kinetic () parameters at 30-70 °C showed that displayed a higher resistance to thermal inactivation when compared to the free enzyme () and (). The efficiency of cyanide biodegradation from the by the and were 55, 62, and 74% respectively after 6 h. Rhodanese immobilized via had a higher resistance to thermal denaturation over other enzyme forms. Hence, this makes adaptable for large-scale detoxification of cyanide from