BIODEGRADATION POTENTIAL OF NOCARDIA FARCINICA BN26 FOR XENOBIOTICS MINERALISATION

In the present study the catabolic activity of the biosurfactant-producing strain Nocardia farcinica BN26 was followed to prove its potential for bioremediation. These bacteria were examined for their degradation ability by exposing them to different temperatures and 29 C was found as the optimum temperature. The rate of phenol mineralisation by the bacterium using different cell densities was also estimated. The adaptation capabilities of the bacterium in a semicontinuous process with multiple xenobiotic supply was studied. The cells that had undergone 10 passages on 500 mg/l phenol containing medium had the highest capacity for degrading both the aromatic and aliphatic xenobiotics added at equal concentrations. During the biodegradation of the hydrophilic and hydrophobic xenobiotics, the biosurfactant production increased up to 500 mg/l. A significant decrease of the surface tension to 32 mN/m was also registered, accompanied by decreased cell hydrophobicity (29%), in that way favouring the bioremediation process. Simultaneous biodegradation till total depletion of phenol (3.5 g/l) and n-hexadecane (0.5 g/l) for 18-24 h was established for the investigated strain.