Resumo

Studies estimate that merely a small fraction (approximately 0.1-1%) of all microorganisms can be recovered from soil samples by standard cultivation methods. In the late 90’s, a new technique has been presented to analyze the wide diversity of microbial genomes, the metagenomics. Such methodology aims to identify functional information from DNA isolated from environmental samples, such the recognition of the proteins for biotechnological purposes and new industrially exploitable biological resources (e.g. new solutions for oil spill). Novel genes identification related to biosurfactants production to recover areas contamined with oil, besides being an advantageous strategy is environmentally friendly. The environmental DNA (eDNA) was extracted from soil samples collected in two different areas from Rio Grande do Norte state (Caatinga and Saline River) and after random fragmentation (1-2 kb), metagenomic libraries were obtained using the cloning vector pBC (Stratagene®) and functionally analyzed in liquid medium supplemented with Arabian light oil in deep well plates and observed after at 30ºC for 15 days. Gene fragments which degrade oil were evaluated for their ability to synthesize biosurfactant using kerosene emulsification test and droplet collapse, were sequenced, isolated by PCR and thus subcloned into expression vector pETDUET-1 for subsequent protein expression. Assays indicated twelve positive gene fragments; ten belonged to Caatinga library and two, Saline River. All sequences showed similarity to hypothetical proteins. So far, one fragment called 3C6 is in the expression vector. Protein expression and purification experiments are being made. In this study, genes selection coding for hypothetical proteins confirms metagenome as a rich and unexplored in novel genes search. Supported by UFRN, CAPES and CNPq.