Demonstration of bipolar membrane electrodialysis technique for itaconic acid recovery from real fermentation effluent of Aspergillus terreus

The scientific interest towards itaconic acid (IA) recovery (produced industrially from biomass by fermentation) significantly increased from around the last decade. IA is a value-added chemical with key-role in the production of versatile polymers and is potentially able to replace certain petrochemical-based materials. Typically, multi-step crystallization is used as a downstream process for IA recovery but there are several promising alternatives. One of them is the application of electrodialysis in the concept of integrated fermentation-membrane system. However, there are still limited publications in this topic especially dealing with the processing of real IA fermentation broth. Hence, in this study, the feasibility of IA separation was assessed from fermentation broths (containing 22−25 g/L of IA) produced by Aspergillus terreus using commercialized electrodialysis unit applying mono- and bipolar membranes. The experimental results showed that the IA recovery ratio/current efficiency were 74%/77% and 63%/41% under initial pH of 3.0 and 7.4, respectively. It was also found that higher initial pH resulted in faster IA separation thanks to the presence of additional mobile ions but at the same time, it decreased the current efficiency. Moreover, partial retain of colorants could be attained during the separation. However, the by-products decreased the separation efficiency compared to our previous measurements conducted with model IA solutions.