OPTIMIZATION OF MEDIUM COMPOSITION FOR EXTRACELLUAR PROTEASES PRODUCTION BY Pseudomonas sp. IN SUBMERGED FERMENTARION

Abstract

Microbial proteases are the most important group in the enzymes world market, because have several industrial applications. Moreover, they have some advantages respect to proteases produced by other sources, such as to have more stability and to be excreted to fermentation medium. The genus Pseudomonas has been studied as a protease producer of enzymes with industrial potential. Nevertheless, the production is affected by factors such as medium composition and culture conditions, and their optimization lead to reduce costs and increase yield. In this context, medium components that influenced significantly in production of Pseudomonas sp. M211 extracellular proteases in submerged fermentation were determined. In this work, one-factor-at-a-time method was used to assess the effect of different carbon, nitrogen and ions sources in proteases production. The highest level of extracellular proteases was obtained in medium containing carbon sources: glycerol, maltose, galactose or glucose; nitrogen sources: peptone, beef extract, yeast extract or NH4 Cl; and ions: CaCl2 or KCl. Further, these factors were selected to elaborate Plackett-Burman experimental design. The factors were tested at two levels, high (+1) and low (-1), five center points and 33 trials in duplicate. As a result of Plackett-Burman design analysis, yeast extract and peptone were identified with statistically significant effects (p value < 0, 05).