Formation of Levan from Raffinose by Levansucrase of <i>Zymomonas mobilis</i>

Abstract

Abstract Levansucrase (EC 2.4.1.10.) of Zymomonas mobilis 113S can perform the polymerisation of fructose moiety from raffinose to levan concomitantly with a release of non‐catabolised melibiose into the medium. The kinetic parameters of the levansucrase‐catalysed reaction provide even higher reaction velocities on raffinose as compared to sucrose, particularly at low substrate concentrations. A decreased value in the number of the average molecular mass ( M n = 1693 kDa), an increased intrinsic viscosity (η = 49.47 cm 3 /g), and a diminished Huggin's constant ( K ' = 0.67) are intrinsic to the levan synthesis from raffinose, indicating certain structural peculiarities compared to a polysaccharide obtained from sucrose ( M n = 1851 kDa, [η] = 42.47 cm 3 /g, K ' = 1.21).