Purification and biochemical characterization of an extracellular fructosyltransferase-rich extract produced by Aspergillus tamarii Kita UCP1279

The market for prebiotics is gaining strength and is growing greatly in recent years since the consumers demand are changing and are highly influenced by the increasing consumption of healthier products. The fructosyltransferase (FTase) mainly produced by filamentous fungi is responsible for the synthesis of fructooligosaccharides which are widely used as a bioactive ingredient in functional foods. The objectives of this work were to select the best Aspergillus strains fructosyltransferase producer, purify FTase using ion-exchange chromatography coupled to FPLC under Superdex-G75 and to produce fructooligosaccharides. Six strains of Aspergillus sp. were studied, and A. tamarii Kita was highlighted because of the greater fructosyltransferase activity. At the production stage, the maximum activity of crude extract (1629.03 U/gds) was obtained under the following conditions: wheat bran 3.0g, sucrose concentration at 20%, 106 spore/mL, 70% moisture, 12h in the presence of light, at 30 °C for 48h. Superdex-G75 was able to purify the enzyme with high activity, and after SDS-PAGE under zymography conditions, one band of protein was observed at 89.7 kDa. The specific activity of the final purified material was 112,629.03 U/gds with purification ratio of 49 times and yield of 36%. FTase presented optimum temperature at 60 °C and pH 5.0, respectively. Together, these results indicated that the FTase of Aspergillus tamarii Kita is an excellent candidate for the industrial production of FOS. •Extracellular fructosyltransferase (FTase) (~89.7 kDa) from Aspergillus tamarii Kita was purified and characterized.•The purification of FTase was performed at room temperature on a fast protein liquid chromatography system.•The specific activity of the FTase was 112,629.03 U/gds with purification ratio of 49 times and yield of 36%.•FTase purified by A. tamarii presented optimum temperature at 60°C and pH 5.0, respectively.•FTase executed by A. tamarii generate economical production of fructooligosaccharides.