PROMOTING ACCESS TO AFRICAN RESEARCH

African Journal of Biotechnology

Log in or Register to get access to full text downloads.

Remember me or Register



Studies on aerobic biodegradation activities of 2,4- dichlorophenoxyacetic acid by bacteria species isolated from petroleum polluted site

OE Igbinosa, OS Ajisebutu, IA Okoh

Abstract


Bacteria species were screened and monitored for the efficiency of 2,4–dichlorophenoxyacetic acid (2,4-D) degradation from oil degrading laboratory stock with the view to getting the most efficient 2,4-D
degraders, to develop an active indigenous bacterial consortium for the bioremediation of 2, 4-D polluted systems in Nigeria. The 2,4-D was utilized as sole source of carbon attaining maximum cell densities of 107 cfu ml-1 from an initial 105 cfu ml-1 in 10 days. The amount of 2,4-D utilized in a batch culture by the isolates varied significantly from an initial inoculum densities of the order of 105 cfu ml-1 and increased with increasing concentrations of 2,4-D. Growth rates ranged from 0.154 h-1 to 0.180 h-1 for SERU2 and 0.158 h-1 to 0.183 h-1 for SERU 11. Dioxygenase specific activity [ìg ml-1 chloride
released/mg protein)-1 h-1] in actively growing cell cultures ranged from 0.010 – 0.055 (SERU 2) and 0.009-0.045 (SERU 11). The specific activity of the dioxygenase in the cell-free system ranged between 0.013 – 0.042 (SERU 2) and 0.011-0.046 (SERU 11). The pH optimum for the dioxygenase of the cell-free system was between 7.6 and 8.0 while the temperature optimum was 30oC. In conclusion the results showed that the two bacteria isolates have potential for 2,4-Dichlorophenoxyacetic acid degradation and their cell-free extracts could be used as biological alternatives in the bioremediation of 2,4-D
contaminated system.



AJOL African Journals Online