Biodegradação do ácido 2,4- diclorofenoxiacético (2,4-D) por Burkholderia sp. SMF042

Abstract

Burkholderia bacteria it has ability to biodegrade pollutants considered numerous compounds. By the above, this study aimed to identify molecular SMF042 come from an isolated collection of Burkholderia species, verify their ability to biodegrade the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), to identify the enzymes involved in this process by electrophoresis two-dimensional (2D) and to analyze the expression of genes and TFDA tfdB track TFD biodegradation of 2,4-D. In order to make the extraction of RNA and protein bacterial growth was performed in two culture media BH (mineral medium), a control supplemented with glucose (600 mg / L) and another supplemented with 2,4-D (600 mg / L). RNA extraction was performed in the logarithmic phase while protein extraction was done at the beginning of the stationary phase of bacterial growth. The extracted proteins from two-dimensional map was determined for each reference condition. The adjustment of images of two-dimensional gels, the protein spot detection and evaluation of data to determine quantitative and qualitative changes, molecular weight (MW) and isoelectric point (pI) of the spots was made by the ImageMaster software and analysis of gene expression was qRT-PCR performed by using the method of relative expression 2-ΔΔCT. Through the analysis of the 16S rRNA isolate SMF042 was identified as Burkholderia phymatum. Regarding proteomics approach, the average number of spots of the replicas of the gels was 535 (control) and 705 (treated). The most abundant protein in the gels was observed in the range of 20 and 40 MW kDa and pH 5 and 6. Enzymes involved in the biodegradation of 2,4-D were identified using the values of pI and MW of spot against a database of proteins at ExPASy, they were: 2,4-D alpha KG-dependent dioxygenase (TFDA) and chlorocatechol 1 ,2-dioxygenase (tfdC) belonging saw PDT and 2,4-D oxygenase pathway cadRABK, both biodegradation of 2,4-D. Proteins involved in resistance to chemical stress, have also been identified, which are: protein chaperone DnaK and GrpE. The level of gene expression TFDA increased about 23 times compared to control. As shown, the isolated SMF042 was able to grow on a medium containing 2,4-D as sole carbon source expressed protein degradation pathways of 2,4-D, resistance to chemical stress and increased expression of gene TFDA, which indicates the importance of this bacterium in this pollutant biodegradation