Biodegradation Kinetics of Free Cyanide in Fusarium oxysporum-Beta vulgaris Waste-metal (As, Cu, Fe, Pb, Zn) Cultures under Alkaline Conditions

24 Aug 2016

The kinetics of free cyanide biodegradation were investigated under simulated winter (5 ?C) and optimum conditions (22 ?C and pH of 11) using a Fusarium oxysporum isolate grown on Beta vulgaris waste as a sole carbon source in the presence of heavy metals, i.e. As, Fe, Cu, Pb, and Zn. The highest free cyanide degradation efficiency was 77% and 51% at 22 ?C and 5 ?C respectively, in cultures containing free cyanide concentration of 100 mg F-CN/L. When compared with the simulated winter conditions (5 ?C), the specific population growth rate increased 4-fold, 5-fold, and 6-fold in 100, 200 and 300 mg F-CN/L, respectively, for cultures incubated at 22 ?C in comparison to cultures at 5 ?C; an indication that the Fusarium oxysporum cyanide degrading isolate prefers a higher temperature for growth and cyanide biodegradation purposes. The estimated energy of activation for cellular respiration during cyanide degradation was 44.9, 54, and 63.5 kJ/mol for 100, 200, and 300 mg F-CN/L cultures, respectively, for the change in temperature from 5 to 22 ?C