Microorganisms represent the most abundant biomass on the planet; however, because of several cultivation technique limitations, most of this genetic patrimony has been inaccessible. Due to the advent of metagenomic methodologies, such limitations have been overcome. Prevailing over these limitations enabled the genetic pool of non-cultivable microorganisms to be exploited for improvements in the development of biotechnological products. By utilising a metagenomic approach, we identified a new gene related to biosurfactant production and hydrocarbon degradation. Environmental DNA was extracted from soil samples collected on the banks of the Jundiaí River (Natal, Brazil), and a metagenomic library was constructed. Functional screening identified the clone 3C6, which was positive for the biosurfactant protein and revealed an open reading frame (ORF) with high similarity to sequences encoding a hypothetical protein from species of the family Halobacteriaceae. This protein was purified and exhibited biosurfactant activity. Due to these properties, this protein was named metagenomic biosurfactant protein 1 (MBSP1). In addition, E. coli Rosetta tM (DE3) strain cells transformed with the MBSP1 clone showed an increase in aliphatic hydrocarbon degradation. In this study, we described a single gene encoding a protein with marked tensoactive properties that can be produced in a host cell, such as Escherichia coli, without substrate dependence. Furthermore, MBSP1 has been demonstrated as the first protein with these characteristics described in the Archaea or Bacteria domains.Surfactants are amphipathic compounds that have a hydrophobic moiety that is directed towards the surface and a hydrophilic portion that is directed towards the solution 1 . These amphiphilic molecules can reduce surface tension at air/water and oil/water interfaces 2,3 . Surfactants produced by organisms are called biosurfactants, which are extracellular products or components within the cell membranes of prokaryotes and eukaryotes 1,4,5 . Biosurfactants are classified into four major categories: glycolipids, fatty acids, lipopeptides, and polymeric types. These categories are represented by amphipathic polysaccharides, lipopolysaccharides, lipoproteins, fatty acids, or complex mixtures of these biopolymers. In general, the synthesis of biosurfactants involves elaborate genetic systems, including operons, non-ribosomal peptide synthetases, and/or multiprotein assembly complexes 6-9 .The synthesis of biosurfactants occurs in the presence of different substrates as a carbon source. To reduce production costs, cheaper substrates have been used. The most commonly used substrates for biosurfactant production are agro-industrial products such as molasses, marc, or vegetable oils 6-8 . Rhamnolipids and surfactin are among the best studied biosurfactants. Rhamnolipids are glycolipids first discovered in Pseudomonas aeruginosa, which are formed by the bonding between a rhamnose moiety and a 3-(3-hydroxyalkanoyloxy)alkanoic acid (HAA) fatty acid tail. The essen...
