Degradation of volatile fatty acids by differently enriched methanogenic cultures: Kinetics and inhibition

The kinetic parameters of volatile fatty acids (VFA) degradation were studied for two methanogenic populations previously enriched in continuous digesters feed with acetate or glucose as the main carbon source. Progress curves for VFA utilization were used to calculate Ks and Vmax, and comparison between results obtained for both inocula is made using substrate affinities for acetic, propionic, n-butyric and i-butyric acids. Inhibition of the acetate degradation by VFA, bromoethane-sulfonic acid (BESA) and vancomycin was also analysed. The results suggested that sludges acclimatized to the presence of VFA arising from substrate degradation could use them better than not acclimatized sludge.