beta-fructofuranosidase (EC 3.2.1.26) from Aspergillus sp 27H isolated from soil was investigated for production of fructooligosaccharides (FOS) using whole cells. It possesses hydrolytic and transfructosylating activities that can be altered by modifying the reaction conditions. The optimal conditions for the transfructosylating activity occur in the pH range 5.5-6.0 and at 60 degreesC, while hydrolytic activity was highest at pH 4.0 and 55 degreesC. At low sucrose concentration (10 g dm(-3)) there was rapid conversion of sucrose to glucose and fructose and very low concentrations of FOS were obtained. However, at sucrose concentrations higher than 216 g dm(-3) the concentrations of hydrolysis products were reduced. Under the following conditions: pH 5.5, temperature 40 degreesC, sucrose concentration 615 g dm(-3) and enzyme concentration 20beta-fructofuranosidase units g(-1) of sucrose, the FOS concentration reached a maximum value of 376 g dm(-3) (234 g dm(-3) 1-kestose and 142 g dm(-3) nystose) and the proportion of FOS in the solids in the reaction mixture was 600-620 g kg(-1) at 6 h. These results suggest that beta-fructofuranosidase from Aspergillus sp 27H could be an appropriate enzyme for the commercial production of FOS. (C) 2004 Society of Chemical Industry.