Partial Purification and Characterization of Extracellular Fructofuranosidase with Transfructosylating Activity from Candida sp.

The present work was carried out with the aim to investigate some properties of an extracellular fructofuranosidase enzyme, with high transfructosylating activity, from Candida sp. LEB-I3 (Laboratory of Bioprocess Engineering, Unicamp, Brazil). The enzyme was produced through fermentation, and after cell separation from the fermented medium, the enzyme was concentrated by ethanol precipitation and than purified by anion exchange chromatography. The enzyme exhibited both fructofuranosidase (FA) and fructosyltransferase (FTA) activities on a low and high sucrose concentration. With sucrose as the substrate, the data fitted the Michaellis-Menten model for FA, showing rather a substrate inhibitory shape for fructosyltransferase activity. The K (m) and v (max) values were shown to be 13.4 g L-1 and 21.0 mu mol mL(-1) min(-1) and 25.5 g L-1 and 52.5 mu mol mL(-1) min(-1) for FA and FTA activities, respectively. FTA presented an inhibitory factor K (i) of 729.8 g L-1. The optimum conditions for FA activity were found to be pH 3.25-3.5 and temperatures around 69 A degrees C, while for FTA, the optimum condition were 65 A degrees C (+/- 2 A degrees C) and pH 4.00 (+/- 0.25). Both activities were very stable at temperatures below 60 A degrees C, while for FA, the best stability occurred at pH 5.0 and for FTA at pH 4.5-5.0. Despite the strong fructofuranosidase activity, causing hydrolysis of the fructooligosaccharides (FOS), the high transfructosilating activity allows a high FOS production from sucrose (44%).