Mapping atrazine and phenol degradation genes in Pseudomonas sp EGD-AKN5

Bacterial isolates with multi-substrate degradation capacities are good candidates for bioremediation of environmental niches. Lab isolate Pseudomonas sp. EGD-AKN5 was found to degrade atrazine, benzoate, phenol, toluene and catechol at the rate of 1.88 +/- 0.01, 16.5 +/- 1.37, 9.08 +/- 2.20, 3.86 +/- 0.11, and 3.3 +/- 0.29 mg L-1 h(-1), respectively. Draft genome sequence analysis demonstrated the presence of the complete degradation pathway for atrazine and phenol. Gene annotation results indicated that atrazine was degraded via the chlorohydrolase route with atzA/B/C/D/E/F genes, while phenol was converted to catechol via a multicomponent phenol hydroxylase from the phc pathway. Genes from the ortho pathway were responsible for the further biodegradation of catechol; a result that was confirmed by enzyme assays. A model to describe the growth and biodegradation of atrazine, phenol and related compounds was applied and fit to a series of aerobic batch degradation experiments. Kinetic studies revealed that EGD-AKN5 showed potential to degrade both phenol and atrazine simultaneously using phenol as the carbon source and atrazine as nitrogen source. Gene expression studies indicated a longer lag phase for expression of genes from the atrazine degradation pathway, when compared to expression of phenol and catechol degradation. (C) 2015 Elsevier B.V. All rights reserved.