Biodegradation of 3,4-dichlorobenzoic acid by Corynebacterium argentoratense
- Details
- Category: Biological Sciences
- Published: Tuesday, 08 May 2012 03:00
- Written by Shadia Saleh AL-Majali
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Abstract
Biodegradation of 3,4-dichlorobenzoic acid by Corynebacterium argentoratense
Shadia Saleh AL-Majali
Mu'tah University,2010
In this study, the bacterium C. argentoratense was isolated from the wastewater treatment plant of Petra City which is located in southern Jordan. Its identification was detected using morphological and biochemical characteristics. The best concentration caused the higher degradation percentage was the 4 mM concentration. The maximum degradation level of 4mM 3,4-dCBA was achieved in 20 hours of incubation time. The effect of four incubation temperatures (25, 30,37, and 42oC) were tested to investigate their effect on the biodegradation of 3,4-dCBA .The experiments on the degradation percentage at different incubation temperature were used by two ways; without glucose and plus glucose. Bacterial cells grown in glucose-MSM media resulted slightly in higher degradation percentage in contrast with the glucose-free-MSM media. Irrespective whether the culture media contain glucose or not, the C. argentoratense cells optimally degrade the 3,4-dCBA at a pH of 7.5. C. argentoratense cells were carbon starved for 24 and 48 hours. The 3,4-dCBA degradation by carbon-starved C. argentoratense for 48h was more advantageous than that of 24 h starved and nonstarved cells, respectively. the starved cells requested only 20 h to reach the maximal limit of degradation percentage compared to the control cells that were achieved within longer period. When our isolate was pre-starved for 24 and 48 h, the degradation ability of 3,4-dCBA had clearly commenced after a shorter acclimation period, become slightly faster, and the endpoint (final degradation percentage) was accomplished in a shorter time, compared with that of the non-starved cells. It is important to unify the optimum conditions in one experiment to inspect the maximal outcome for biodegradation, cell growth and therefore Cl release. The adaptation of C. argentoratense cells clearly showed an important factor for improving the degradation ability. It is clearly shown that the 1,2-dioxygenase activity-dependent-ortho cleavage pathway for 3,4—dCBA substrate is the only option.