The present invention relates to genetically modified microorganisms capable of producing beta-glucans, characterized in that the genetically modified microorganism overexpresses (i) a polynucleotide encoding a polypeptide having 1,3-β-D-glucan synthase-activity, and/or (ii) a polypeptide having 1,3-β-D-glucan synthase-activity, compared to a corresponding non-modified control microorganism of the same strain. The present invention also relates to the use of a polynucleotide encoding a polypeptide having 1,3-β-D-glucan synthase-activity or the use of such a polypeptide for producing β-glucans. Furthermore, the present invention relates to methods for producing β-glucans comprising the introduction of a promoter upstream of a polynucleotide encoding a polypeptide having 1,3-β-D-glucan synthase-activity thereby increasing the expression of the polynucleotide, or a polynucleotide encoding a polypeptide having 1,3-β-D-glucan synthase-activity into a microorganism being able to synthesize β-glucans.