Solid culture medium for micro-organisms and eukaryotic cells and the production method of same

A solid culture medium which is intended, in particular, for micro-organisms and eukaryotic cells. The medium includes, by way of a gelling base, a polysaccharide having a reproduction unit including a side chain and six neutral sugars, including glucose and galactose, and an acid sugar, pyruvate substituents and acetates being present. A solution in water or a saline solution having a concentration of the polysaccharide which is greater than or equal to 2 g/l forms an elastic transparent gel.