The Isolation, Characterization, and Diesel Oil Denitrification of a Quinoline-Degrading Bacteria

Abstract

Quinoline is a poisonous organic compound and not easily biodegraded. From soil, wastewater, and activated sludge 19 bacterial strains were isolated by enrichment culture, which are able to use quinoline as the sole nitrogen source. Of the 19 strains, the HY9 strain is the best quinoline-degradation bacterium. Curves of the growth of HY9 and degradation of quinoline show that the growth of the HY9 strain and degradation of quinoline are concurrent, the optimum time is 50–70 hr, which is the stationary phase. Effects of carbon resource and the quantity of initial quinoline on degradation of quinoline are studied. The optimal carbon resource and quantity of initial quinoline amount are glucose 0.14 mL/100 mL. The orthogonal test determined optimal temperature, pH, time, and agitation speed, which are respectively 35°C, 7.0, 4 days, 125 rev/min. Temperature is the key factor, followed by pH and agitation speed, and time of culture is the least important factor. The denitrification rate of diesel oil is very low, only 13%. This is probably because the oil and water could not mix well; the key to strengthening the compatibility of oil and water is to try to improve the denitrification rate of diesel oil.