THE INFLUENCE OF A SPECIFIC MICROELEMENTAL ENVIRONMENT IN ALGINATE GEL BEADS ON THE COURSE OF PROPIONIC-ACID FERMENTATION

In this work the exchange of calcium, cobalt, iron, magnesium, zinc an d manganese ions between alginate gel beads and casein medium was inve stigated. The high release of calcium ions from alginate to the medium and the biosorption of some metal ions were observed. The pure algina te gel adsorbed all the metal ions examined, from a fermentative mediu m. Gel with immobilized cells of two strains of Propionibacterium freu denreichii subsp, shermanii showed an active ability to adsorb only co balt, iron and zinc ions. In this way, a special microelemental enviro nment was created in the alginate gel. This resulted in an increase of propionic acid production and a decrease of vitamin B-12 biosynthesis .