Evaluation of Differentially Expressed Candidate Genes in Benzo[a]pyrene Degradation by Burkholderia vietnamiensis G4.

ABSTRACT

Bacteria-mediated bioremediation is widely employed for its environmental benefits. The genus Burkholderia can degrade persistent organic compounds, however, little is known about its mechanisms. To increase this knowledge, Burkholderia vietnamiensis G4 bacteria were exposed to benzo[a]pyrene, a recalcitrant compound, and the expression of twelve genes of interest was analyzed at 1, 12 and 24 h. In addition, benzo[a]pyrene degradation, evaluation of cell viability and fluorescence emission of assimilated benzo[a]pyrene was performed over 28 days. The up-regulated genes were xre, paaE, livG and pckA at the three times, ACAD, atoB, bmoA and proV at 1 h and AstB at 12 h. These genes are important for bacterial survival in stress situations, breakdown and metabolization of organic compounds, and nutrient transport and uptake. Furthermore, a 52% reduction of the pollutant was observed, there was no significant variation in the viability rate of the cells, and fluorescence indicated an accumulation of benzo[a]pyrene after 24 h. Our study demonstrates the bacteria adaptability and ability to modulate the expression of genes at different times and as needed. This increases our understanding of biodegradation processes and opens new possibilities for using this bacterial strain as a tool for the bioremediation of contaminated areas.