Integrated in-situ product removal process concept for itaconic acid by reactive extraction, pH-shift back extraction and purification by pH-shift crystallization

A key challenge for the realization of a biobased economy is the processing of diluted aqueous streams from biotechnological conversion processes. Therefore, established methods need to be reviewed in detail and synergies in the overall process design have to be utilized to gain economic competitiveness. In this work, an integrated recovery of itaconic acid (IA) by in-situ product removal (ISPR) and purification from a diluted aqueous fermentation broth to IA in crystalline solid state is shown. Thus, a process concept including reactive extraction, back extraction and crystallization is used. An integration of product recovery, concentration and purification can be achieved using the pH dependent properties of IA. This unique process set-up makes a new crystallization concept for IA via pH-shift crystallization possible. Based on the presented equilibrium and kinetic data, operating windows for each unit operation were determined. Main advantages of the process concept are that the usage of thermal energy is avoided, IA losses are minimized and the fermentation can be performed under optimal pH operating conditions at maximal space-time-yield.