Genetic and functional characterization of Lactobacillus panis levansucrase.

Exopolysaccharides (EPS) can affect the rheological properties of foods, act as stabilizers or stimulate preferential growth of bifidobacteria in the gut and therefore function as prebiotics. The latter is referred to fructans, which are synthesized from sucrose by fructosyl transferases (FTFs). In this work, the FTF enzyme of Lactobacillus panis TMW1.648 isolated from sourdough was characterized. The coding gene was identified, sequenced and expressed heterologously in E. coli. Enzyme activity was maximal at pH 4.0-4.6, 45 degrees C and a substrate concentration of 300 mmol l(-1). It produced free fructose, a high molecular fructan and the oligosaccharide kestose from sucrose. Calcium ions proved to be essential for the enzymatic activity. In comparison to published data of other FTF enzymes of lactobacilli the described enzyme showed significant differences.