Microbial Fructosyltransferase: Production by Submerged Fermentation and Evaluation of pH and Temperature Effects on Transfructosylation and Hydrolytic Enzymatic Activities

Abstract

Fructosyltransferases (FTase, E.C. 2.4.1.9) are enzymes that catalyze transfructosylation reactions obtaining, as final product, fructose oligomers. In terms of industrial production, the use of microbial enzymes is interesting, especially those produced by Aspergillus sp. The aim of the work was to study the production of FTase by submerged fermentation and evaluation of pH and temperature effects on fructosyltransferase activity. The enzyme was produced by Aspergillus oryzae IPT 301 in a 10-liter bioreactor with growth medium containing sucrose as main carbon source. The assay was performed at 800 rpm, 30 °C, 0.75 vvm and pH 4.5. Transfructosylation (At) and hydrolytic (Ah) activities were determined in the temperature range from 35 to 65 °C and pH range from 3.5 to 6.0. It was observed that mycelial is increases with temperature, holding the maximum value at 50 – 65 oC, while the optimum pH value were 5.0. The optimum temperature for extracellular At ranged from 55 to 65 °C and the optimum pH ranged from 5.0 to 6.0. Furthermore, the optimum temperature for mycelial Ah was 65 °C and optimum pH 4.5 – 5.0. For extracellular Ah, the optimum temperature and optimum pH were 55 to 65 °C and 3.5 to 6.0, respectively.