SIMPLIFIED ANALYSIS OF BIODEGRADATION KINETICS OF PHENOLIC-COMPOUNDS BY HETEROGENEOUS CULTURES

A simplified approach to the determination of biokinetic parameters for phenol and ortho-cresol degradation by heterogeneous microbial cultures, which involved a modified kinetic model and inoculating acclimated microbial cultures with low substrate concentrations, was undertaken. The growth rate data for the two compounds conformed to the Monod model with the maximum specific growth rate, mu(max) and the half-saturation concentration, K(s), for phenol ranging from 0.44 to 3.3 days-1 and from 5.9 to 18 mg l-1 respectively. The corresponding values for o-cresol were 0.7 to 2.0 days-1 and 9.3 to 40.7 mg l-1. The bacterial yield coefficients for phenol and o-cresol were 0.53 and 0.60 mg VSS (mg substrate)-1, respectively with corresponding decay rates of 0.16 and 0.13 days-1. The simplified approach yielded results that are comparable to those of more sophisticated experimental and mathematical techniques.