Bioprospecção de actinomicetos isolados de solos no Estado da Bahia e seu potencial biotecnológico na produção de enzimas lignocelulolíticas

Abstract

Actinomycetes are Gram-positive bacteria with filamentous growth, usually found in diverse environments, including water, air, composting material, and others, and soil your shell more common. The major industrial interest due to its ability to produce different antibiotics and a variety of enzymes capable of hydrolyzing substrates containing cellulose, hemicellulose and lignin. Annually, farming generates large amounts of organic residues, creating a variety of environmental and social problems, and this situation has encouraged the use of technologies capable of converting lignocellulosic materials into ethanol. Against this backdrop, this study aimed to isolate and select actinomycetes in different soils of Bahia, producing enzymes of industrial interest and evaluate their biotechnological potential. 196 actinomycetes were isolated from five different soil samples, and 111 cellulolytic and 97 xylanolytic strains. The CDPA-01 strain, identified as Streptomyces sp. was selected as the most promising as the production of cellulases. The enzyme production was conducted in Submerged Fermentation, using three different carbon sources (oat bran, carboxymethylcellulose and sugarcane bagasse) under varying concentrations and a single source of nitrogen (Milhocina) by central composite design, CCRD (11 trials). The higher production of cellulase (0.740 U.mL-1) was observed when using 1.6% (w/v) sugarcane bagasse and 1.51% (w/v) of corn steep liquor, 8 in the test, after 5 days of fermentation. After validation, the best activity of the extracts was characterized and the optimum temperature and pH were 60 °C and 4.0, respectively, the enzyme proved to be thermostable at 50 °C and the ions tested did not act as cofactors in enzymatic activity. Thus, the preliminary results of this study indicate that the micro-organism studied and the substrate used has a high potential for production of cellulase.