Continuous itaconic acid production by immobilized biocatalysts.

The continuous itaconic acid production from sucrose with Aspergillus terreus TKK 200-5-3 mycelium immobilized on polyurethane foam cubes was optimized in column bioreactors using statistical experimental design and empirical modelling. The highest itaconic acid product concentration calculated on the basis of the obtained model was 15.8 g l-1 in the investigated experimental area, when sucrose concentration was 13.5%, aeration rate 150 ml min-1 and residence time 178 h. From sucrose with immobilized A. terreus TKK 200-5-3 mycelium itaconic acid production was stable for at least 4.5 months in continuous column bioreactors. In comparison, using glucose as substrate and immobilized A. terreus TKK 200-5-1 mycelium as biocatalyst similar stability was obtained with higher product concentration. The omission of copper sulphate from the production medium gave the highest itaconic acid product concentration (26 g l-1) from 9% glucose with 0.25% ammonium nitrate and 0.095% magnesium sulphate.