A Comparative Study on Biodegradation of Chlorobenzene by Pseudomonas aeruginosa, Nocardia hydrocarboxydanse and Mycoplanadimorpha

Microorganisms have the ability to conform to a variety of environmental conditions. Their versatility makes them useful for various biotechnological applications. One such application is the use of microorganisms for removal of pollutants from the environment, called bioremediation. The first goal of the present work was to identify a microorganism which could grow on the model pollutant monochlorobenzene. The microbes used for degradation are Pseudomonas aeruginosa, Nocardia hydrocarboxydanse, and Mycoplana dimorpha.The batch-wise degradation is carried out on a laboratory scale using monochlorobenzene (MCB) as a substrate. The pH and temperature were maintained at 7.0 and 30°C throughout the experiment. The degradation was studied at various substrate concentrations (100, 200, 500 ppm.). Following a 2-5 hr post-treatment lag phase, degradation of the substrate occurred within 48 h.Various factors such as inocula, concentration of chlorinated aromatic hydrocarbons (CAHs), pH, temperature, presence of co-substrates and the type of carbon source used influenced the degradation of CAHs in shake flasks. Results show that the degradation was highest at an initial concentration of 200 ppm of MCB by Pseudomonas aeruginosa. Results also show that when the substrate concentration was increased to 500 ppm, the degradation became slower.