Resumo

The mangroves are distributed widely in tropical and subtropical regions of the whole planet, occupying 60 to 75% of this area. Positioned at the interface between marine and terrestrial, are located in flood plains and have a great variation of salinity situated between 5 to 30 %. Its ecological importance consists in: keep the food chain, prevent soil erosion by tides, reduce the silting up of harbors and reduce the impacts resulting from the leaching of chemical compounds. The mangroves have high levels of organic matter, and the microbial activity are responsible for turning this dead vegetation in sources of nitrogen, phosphorus and other nutrients that may be used by plants. In general, the microorganisms present in this ecosystem have the capacity to degrade lignocellulosic biomass. Cellulases and xylanases are important enzymes capable of transforming the cellulose and hemicellulose, respectively, molecules that can be used to generate value-added products. These enzymes are widely used in the food industry, pharmaceutical, agriculture and production of second generation fuels. Environments such as the mangroves may represent a promising source and unexplored for the screening of cellulases and xylanases microbial with biotechnological potential. In this context, we conducted a prospecting of these enzymes in a metagenomic library (12,960 clones) constructed from DNA retrieved from mangrove sediment samples. For screening of the clones producing the cellulase and xylanase we used the minimal medium supplemented with 1% CMC and 0.2% xylan as the sole carbon source. The plates were incubated for 4 days at 37° C. The enzyme activity was evidenced by the addition of a solution of iodine (2.0 g of KI and 1.0 g iodine in 300 ml of distilled water). The presence of clearly zone around the colony indicated production and secretion of cellulases and xylanase. Using this method it was possible to identify and two clones a clone xilanolíticos cellulolytic. Future studies will be conducted to characterize the enzymatic activity of these positive clones.