Bipolar membrane electrodialysis integration into the biotechnological production of itaconic acid: A proof-of-concept study

Itaconic acid is a promising biobased organic acid that can be industrially produced in an eco-friendly way by aerobic fungal fermentation. It has many applications, e.g. in biopolymers, and has the potential to help replace or facilitate the green production of other similar but fossil-based chemicals. Nowadays, its production costs are still relatively high, partly due to the multistep product recovery process from the fermentation broth. In this study, a reduced number of downstream processes were evaluated to recover itaconic acid from model and real fermentation effluents. To the best of our knowledge, this is the first time the whole procedure is presented from the substrates to the solid and pure product, including fermentation, electrodialysis with bipolar membrane, evaporation and optimized crystallization. Based on the fermentation temperature and elevated pH, a synergistic effect was observed that intensified certain mass transfer mechanisms. Consequently, a significant amount of water (400 cm3) and itaconic acid (15 g) was transported into the alkaline concentrate. Moreover, novel outcomes about the condition, decolorization and process enhancements of the membrane (product recovery: 65–80 %, current efficiency: 42–76 %, product purity: 99 %) were recorded. Based on the results, our group is one step closer to the final concept of a continuously operated fermentation-electrodialysis integrated system.