STUDIES ON BIODEGRADATION OF A MIXTURE OF TOXIC AND NONTOXIC POLLUTANT USING ARTHROBACTER SPECIES

The effect of a nontoxic easily degradable substrate, glucose, on the biodegradation of toxic pollutant, phenol, was studied in batch reacto rs using a phenol degrading culture (Arthrobacter species). The effect of glucose on phenol degradation was determined at different glucose concentrations. The effect of different inoculum on substrate removal in a phenol and glucose mixture was also studied. Results indicated th at when a mixed substrate (phenol and glucose) was used, phenol acclim ated population showed an initial preference for phenol and utilised g lucose after phenol removal. However phenol degradation rate was reduc ed in the presence of glucose. It was also observed that phenol degrad ation was completely inhibited when the glucose concentration exceeds 2 g/l. The substrate removal pattern changed completely when inoculum was drawn from mixed substrate acclimatised culture. The glucose utili sation started immediately and the rate of glucose utilisation was not affected by the presence of phenol. The phenol degradation also start ed simultaneously. In presence of phenol only, the rate of phenol degr adation for the culture acclimatised to mixed substrates was lower tha n that of phenol acclimatised culture. These results indicate that non toxic substrate can affect the biodegradation of toxic pollutants is s uitable and acclimatisation may be necessary for biodegradation of mix ed substrate.