STUDIES ON FACTORS INFLUENCING THE BIODEGRADATION OF PENTACHLOROPHENOL BY A MIXED BACTERIAL CULTURE

Augmentation of a pentachlorophenol (PCP)/salts medium with glucose and peptone dramatically increased rate and extent of PCP degradation. Over a 6-day incubation period, 80% of the initial PCP was degraded. The PCP degradation rate was further accelerated by prior acclimation of the mixed culture inoculum for 2-3 days in the same culture medium. This acclimation protocol reduced the lag phase for PCP degradation and eliminated up to 86.5% of the PCP after 3 days. PCP biodegradation increased substantially when the mixed culture inoculum size was increased from 10(4) to 10(5) cells ml-1 of degradation medium. The mixed culture was shown to mineralize radiolabelled PCP. When the relative capacity of the mixed culture to degrade di-, tri-, tetra- and pentachlorophenol was compared, rate of PCP degradation was slower than for lower chlorinated phenols.