Dextransucrase is an important clas

Dextransucrase is an important class of extracellular enzymes with great industrial importance. Dextransucrase synthesizes the high
molecular weight glucose polymer dextran by transferring D-glucosyl moieties to a growing glucan chain. Keeping in view the potential
of dextransucrase, bench scale production of Acetobacter tropicalis cells with high dextransucrase activity was carried out in laboratory
fermenter at 7 L scale. The growth of A. tropicalis has been affected by the supply of oxygen during the fermentation. Therefore, the
optimum combination of aeration rate and agitation speed for dextransucrase production from A. tropicalis was found to be 0.5 vvm
and 450 rpm. The volumetric oxygen transfer coefficient, KLa values were found to affect the growth of A. tropicalis and production of
dextransucrase. In the present study, the growth and dextransucrase production increased with increase in KLa upto an optimum limit
and then started decreasing with increase in KLa. Maximum biomass (1.41 mg/ml) and maximum dextransucrase activity (15.8 U/ml)
was obtained at KLa value of 0.28 min-1. The maximum dextransucrase activity obtained in laboratory fermenter was 15.8 U/ml which
was greater than the enzyme level obtained at shake flask level (11.6 U/ml).