Fructooligosaccharides (FOS) are prebiotics that selectively stimulate the growth and activity of lactobacilli and bifidobacteria. These strains metabolize FOS with endogenous beta-fructofuranosidase. In this study, a beta-fructofuranosidase gene from Lactobacillus plantarum ST-Ill designated sacA was cloned into Escherichia coli, and the properties of the recombinant protein (SacA) were examined. The sacA gene encodes a peptide of 501 amino acids with a predicted molecular weight of 56.7 kDa. Sequence alignment revealed the presence of three highly conserved motifs, NDPNG, RDP and EC, indicating that the enzyme belongs to glycoside hydrolase family 32. The predicted three-dimensional structure of the SacA enzyme was similar to beta-fructofuranosidases of bifidobacteria, such that it contained a five-blade beta-propeller module and a beta-sandwich domain with one additional N-terminal a-helix. The optimal reaction temperature and pH of the enzyme were 37 C and 6.0, respectively. Substrate hydrolysis and kinetic parameters demonstrated that beta-fructofuranosidase from L. plantarum ST-III liberated fructosyl residues from the non-reducing terminus of fructans, such as sucrose, FOS, levan or inulin, and FOS was the preferred substrate. The expression of the sacA gene in a non-FOS-fermenting strain, Lactobacillus rhamnosus GG, enabled the recombinant strain to metabolize FOS and sucrose. (C) 2014 Elsevier Ltd. All rights reserved.