Composite ultrathin membranes for clarification and primary recovery of biobased itaconic acid from fermentation broths

Itaconic acid is a biobased organic acid with clear potential to become a relevant renewable building-block chemical. However, to compete with petrochemical processes, the production cost of biobased processes, particularly the downstream processing contribution, needs to be reduced. In this work, composite membranes comprising ultrathin films of crosslinked poly[(o-cresyl glycidyl ether)-co-formaldehyde] and branched polyethyleneimine on mixed cellulose ester supports were developed for application in the primary recovery of itaconic acid from fermentation broths. In contrast to commercial and literature-reported counterparts, these membranes exhibit low itaconic acid rejections over a wide range of pH, ionic strength, organic acid concentration and operating pressure. Moreover, these membranes can efficiently recover itaconic acid from clarified fermentation broth as well as unclarified fermentation broth of Pichia pastoris cultivations, with average rejections below 15% recorded over 8 hours of operation. Lastly, the performance of these membranes was compared to literature-reported strategies for primary recovery of biobased organic acids. The efficient recovery of itaconic acid from unclarified fermentation broth opens the possibility to perform clarification and primary recovery simultaneously, thus simplifying the downstream processing of biobased itaconic acid considerably.