Exopolysaccharide production by Propionibacterium acidi-propionici on milk microfiltrate
2001
Gorret, N. | Maubois, J.L. | Ghoul, M. | Engasser, J.M.
Aims: The aims of this work were to evaluate growth and exopolysaccharide (EPS) production properties of Propionibacterium acidi-propionici DSM 4900 on milk permeate. Methods and Results: Anaerobic growth on milk permeate was only possible if supplemented with yeast extract (YE). Fermentation capacities of the strain were significantly improved by further increasing the supplemented YE. At 5 g l(-1) YE, consumption of 45 g l(-1) lactose to produce 9 g l(-1) biomass, 34 g l(-1) organic acids and 0.65 g l(-1) EPS was observed. From a kinetic point of view, EPS production occurred during the bacteria growth phase. At the excreted polysaccharide level, the medium showed shear-thinning behaviour with a relatively high apparent viscosity of up to 30 mPa.s (milli.Pascal.second) at a shear rate of 17 s(-1). Conclusions: EPS production by P. acidi-propionici DSM 4900 on milk permeate showed promising rheological behaviour of the milk-derived medium obtained, even at a low production level. Significance and Impact of the Study: A kinetic study on EPS production by a food-grade bacterium that could be used in situ in alimentation was carried out.
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