For the conversion of polysaccharides, microbial enzymes play a leading role. Enzyme production starts from pure cultures of a defined stain and is carried out under nearly sterile conditions. The productivity is influenced by choice of nutrition and growth conditions (pH‐value, temperature). Separation, purification and formulation of the enzyme product depends on its intended purpose. Among the naturally occuring polysaccharides degradable by enzymes, starch plays a dominant role in industry. The degree of decomposition of the starch molecule depends on the choice of enzyme (α‐amylase, glucoamylase, etc.) and the process conditions. Beyond that the starch, distilling, brewing and fruit juice industry benefit from the action of cellulases, hemicellulases and pectinases.