Biotreatment of minewater-containing cyanides by using immobilized cell technology

摘要

Cyanide is a metabolic inhibitor and used in large quantities in mining processes. Bacteria can degrade and detoxify these contaminants through normal cellular metabolism. Further, the application of immobilized cell technology in the industrial waste treatment offers the possibility of degrading higher concentrations of toxic pollutants compared to free cells. In this study, Pseudomonas putida and Pseudomonas pseudoalcaligenes, capable of utilizing cyanide as carbon and nitrogen sources were immobilized in calcium alginate in the form of beads and compared the rate of degradation of cyanide. Degradation of potassium cyanide (KCN) to ammonia (NH_3) and carbon dioxide (CO_2) by immobilized cells of P. putida and P. pseudoalcaligenes was studied at pH 6.5 and 9.5. Both cultures were able to degrade KCN effectively at pH 6.5 and pH 9.5. The transfor mation of cyanides present in the minewater to NH_3 and CO_2 by these cultures was also investigated. The study of metals analysis also showed that the calcium-alginate immobilized cells of P. putida and P. pseudoalcaligenes were able to remove metals (Cu, P, Zn As, Co) present in the minewater except Pb. The present study thus concludes that (a) both cultures were able to degrade the cyanides present in the minewater to CO_2 and NH_3; (b) exhibited different rates of degradation and (c) were also able to remove the metals from the sample.