MOLECULAR IDENTIFICATION OF CULTIVATED BACTERIA IN Eisenia foetida Savigny, WITH THE POTENTIAL FOR REMOVAL OF PERSISTENT ORGANIC CONTAMINANTS

Abstract

The use of cultivable methods used to isolate and characterize genotypically the bacteria associated to the intestine of the earthworm (Eisenia foetida Savigny) was evaluated, identifying some genera reported with a potential for removal of persistent organic contaminants (POCs). The earthworms analyzed in addition to peat moss and rabbit manure at the laboratory level established a vermicompost system that was capable of removing 96 % of the decachlorobiphenyl contaminant at a concentration of 200 mg kg^-1 for 91 days. From the pure bacteria strains isolated from the digestive tract of the earthworm, the genomic DNA was extracted and the 16S rDNA gene was amplified, from the DNA extracted from the strains, using the primers fD1 (5´-AGAGTTTGATCCTGGCTCAG-3´) and rD1 (5´-AAGGAGGTGATCCAGCC-3´). All the sequences of the strains were analyzed using the BioEdit v.6 software and aligned with CLUSTAL W, the phylogenetic
trees were built through the MEGA v.5.2 software, using the Tamura-Nei evolutionary model. The taxonomic positions of the strains were determined based on the partial sequences of the chromosome gene 16S rDNA from type bacterial strains, which identified the genera Bacillus, Caryophanon, Staphylococcus, Pseudomonas.