Resumo

The Brazilian Cerrado soil has been the focus of very few studies about its microbial diversity. Soil is a habitat with high diversity of microorganisms and thus it can be used as a source of industrial enzymes. The identification of new genes through molecular approaches such as directed evolution and exploring natural communities by the metagenomic approach led to the development novel enzyme activities.The advantage of directly screening for enzymatic activities from metagenome libraries is that researcher’s access previously unknown genes and their encoded enzymes. Lipases, are an important group of biotechnologically relevant enzymes as they find immense applications in food, detergent, pharmaceutical and biofuel industries. Lipases are mainly produced by microbes more frequently bacterial lipases play a vital role in commercial ventures. To isolate putative lipase genes a small DNA size (8 Kb) Cerrado soil metagenomic libraries were screened with tributirin. The funcional screening of this library resulted in the identification of three lipase activity producing clones that were subsequently sequenced. They revealed 4ORFs with functions related to lypolitic activity. A lipolytic enzyme from the small DNA fragments library of Cerrado soil was isolated and its expression induced in Escherichia coli strain BL21 (DE3), being named LipW. The open reading frame have 1000 pb and encodes a protein containing 300 amino acid residues with estimated molecular weight of 30kDa and strong identity with true lipases. SDS-polyacrylamide gel electrophoresis demonstrates the overexpression of that lipase on inducing conditions. The determination of its optimal activity and enzymatic parameters will lead to more detailed biochemical analysis, in order to propose the use of this product in biodiesel applications, with focus on improvement of production processes. Considering the potential biotechnological application of these enzymes, this work aims at the selection and characterization of 3 novel lipases genes from metagenomic library from soil from savannah-like vegetation suitable for use in biodiesel production.