Nitrite as agent selecting anaerobic phenol-degrading microflora in petroleum refining sediments

The degradation of phenol by microflora of petroleum refining sediments gro wn under conditions favouring denitrification was studied. Incubation of se diments at 30 and 55 degrees C in medium with phenol and nitrate resulted i n complete reduction of nitrate accompanied by accumulation of nitrite. Whe n the sediments were incubated at 30 degrees C in medium with nitrite, phen ol was efficiently removed at nitrite concentrations not exceeding 185 mg N O2--N 1(-1). Prolonged pressure of phenol (2.6 mM) and nitrile (8.2-20 mM) on the microflora of the sediments (three consecutive passages) resulted in gradual loss of denitrification activity with unaltered phenol activity. T he microflora selected from the sediments demonstrated higher phenol activi ty in medium without external electron acceptor than in media with NO3-, NO 2- or SO42-. (C) 2000 Elsevier Science Ltd. All rights reserved.