Influence of cyanide on the anaerobic degradation of glucose

Bacteria in the anaerobic degradation process convert the substrate to the final products methane and carbon dioxide. Toxic substances can change the process substantially. The purpose of this study was to investigate the influence of toxic cyanide on biogas production in anaerobic degradation of glucose at 40°C. The OxiTop respirometric system offers a quick and simple method for measurement of the biogas formed. Concentrations of cyanide (CN⁻) added to 640 mg COD/L of glucose varied from 0.325 up to 31.000 mg/L. The inhibition of anaerobic degradation of glucose was evaluated from the lag phase, the coefficient of anaerobic degradation (D_h), the volume and composition of the biogas and degradation of COD in the liquid phase. If the concentration of cyanide was above 2.600 mg/L inhibition of the anaerobic process was substantial.