Metabolic and technological control of the exopolysaccharide-biosynthesis by mesophilic and thermophilic lactic acid bacteria to improve their production and stability.

Project Details


Many food processes and products are dependent on stable complex interactions between different functional polymers, with polysaccharides (gums of plant origin, animal hydrocolloids, microbial xanthan, etc.) occupying a key role. The production of functional polysaccharides from lactic acid bacteria is a promising alternative. Lactic acid bacteria can produce various exopolysaccharides which may find applications as food viscosifiers or texturizers, particularly in fermented milks. The chemical composition of heteropolysaccharides from lactic acid bacteria is still controversial. Furthermore, these strains produce less slime and the polymer synthesis is very unstable. The varying slime production is disadvantageous for the food industry to guarantee a uniform, te~tural quality of the fermented end product. Finally, almost no quantitative data are available concerning the exopolysaccharide production by lactic acid bacteria, the influence of fermentation conditions on exopolymer biosynthesis and on the subsequent, rheological properties of fermented milk systems. This project aims at the isolation of mesophilic and thermophilic, stable, exopolysaccharide producing lactic acid bacterial strains, and the elucidation of the factors that determine the yield and instability of their exopolymer biosynthesis. This study will also aim to quantify and model the exopolysaccharide production. Hence, it must be possible to better understand the fermentation process for its optimisation and monitoring. All this will contribute to the use of natural, microbial polysaccharides as viscosifier and texturizer, and to an expanded application of starter cultures for the in situ production of desirable phenotypic properties
Effective start/end date1/01/9731/12/97


  • microbiology

Flemish discipline codes

  • Mechanical and manufacturing engineering