[Synthesis of microbial exopolysaccharide ethapolan on ethanol and molasses mix]

A possibility to change glucose, when cultivating exopolysaccharide (EPS) producer etapolan Acinetobacter sp. B-7005 on a mix of C2-C6-compounds, by the inexpensive substrate--molasses has been shown. The highest indices of EPS synthesis were observed under the conditions of preliminary hydrolysis of molasses, availability of growth factors (yeast autholisate and calcium pantothenate) in the medium, lack of the mineral source of nitrogen nutrition and use of inoculation material grown on acetate. In such conditions of cultivation of bacteria on the mix of ethanol (0.75% in volume) and molasses (0.75 wt. % as to carbohydrates) the amount of synthesized EPS reached 10 g/l, EPS-synthesizing capacity--5 g of EPS/g of biomass, the EPS yield from substrate--74% that is 1.3-1.5 times more than in cultivation on molasses. The increase of EPS synthesis on molasses, as well as on etanol and molasses mix with the use of inoculate grown on C2--substrates (compared with the use of inoculate obtained on the medium with molasses) is determined by the induction of gluconeogenesis that was evidenced by the decrease of isocytrate dehydrogenase activity, increase of activity of enzymes of glyoxylate cycle and key enzyme of gluconeogenesis of phosphoenolpyruvate synthetase.