An influence of ethanol and temperature on products formation by different preparations of Zymomonas mobilis extracellular levansucrase

Abstract

The ethanol and temperature effects on the ratio between Zymomonas mobilis 113S extracellular levansucrase activities were studied using fermentation broth supernatant, "levan-levansucrase" sediment precipitated by ethanol and highly purified enzyme. The fructooligosaccharide (FOS) production at different temperatures in the presence of ethanol was investigated. An ethanol increases FOS biosynthesis activity part of levansucrase. Especially, this effect was pronounced at lower temperatures (35-40 °C) and using purified levansucrase. The inverse relationship between temperature and ratio synthetic activity/total activity of levansucrase was found. The FOS composition containing mostly 1-kestose, 6-kestose, and neokestose obtained in the presence of different ethanol concentrations was found relative constant, while the changes in the sucrose concentration and temperature gave slight changes in the ratio between 1-kestose and 6-kestose.