New method for making dextran, dextran solution and uses

A method of producing a microbiologically dextran solution that was inoculated with a preculture of a bacterial strain capable of producing dextran, a culture medium containing sucrose and then directly retrieves the dextran solution obtained in after fermentation, without subsequent concentration step, characterized in that: - before inoculation, the culture medium contains at least 10% by mass of sucrose, - after inoculation, again added sucrose under conditions such that the quantity total sucrose in the medium, including that present prior to inoculation or at least 16% by mass, - the obtained dextran solution contains at least 10% by weight of dextran. native dextran solution obtained and using the solution as a flocculating agent