Produção de proteases por bacillus sp. sob cultivo submerso na presença de resíduos agroindustriais

Abstract

The reuse of agro-industrial waste as sources of carbon and nitrogen has been investigated in biotechnology for the production of enzymes by microorganisms. Among the microbial enzymes imported into Brazil, the proteases are applied in technological processes in the fields of detergents, pharmaceuticals, cosmetics, food, among others. The aim of this work was to produce proteases by submerged cultivation in the presence of agro-industrial waste. The determination of proteolytic activity was in the presence of 0.2 % azocasein. Submerged cultivation of Bacillus sp. strains isolated were carried out in Erlermeyer flasks. The maximum protease activity was determined in the presence of corn steep liquor. The concentration of the liquid metabolic by ultrafiltration of the metabolic liquid with proteolytic activity retained 80% of the activity. A factorial experimental design was carried out to investigate the stability of the metabolic liquid. The maximum proteolitic activity of the liquid metabolic cell-free (196 U/mL) was determined in the presence of 0.5 % sodium sorbate, 0.5 % calcium chloride, and 7.5 % of glycerol and polyethyleneglycol-200. The enzyme extract formulated retained 68 % of the proteolytic activity after 10 days at storage at room temperature (28 ˚C). The retentate with proteolytic activity showed optimum pH 9 and 11 and retention 90 - 100 % of the activity for 90 min at optimum pH; the optimum temperature was 50 ˚C e the maximum thermal stability was at 40 ˚C for 30 min at pH 11. The formulation of metabolic liquid concentrate with proteolytic activity which has thermal stability at alkaline pH is a bioproduct which can be used as an additive in detergents.