Effective separation of bio-based alpha-ketoglutaric acid from post-fermentation broth using bipolar membrane electrodialysis (EDBM) and fouling analysis

In this study bipolar membrane electrodialysis (EDBM) was used in the main process of separation of bio-based alpha-ketoglutaric acid from actual post-fermentation broth. In the first part of this study, simulated broths were used to determine the optimum duration of EDBM process. The effect of pre-treatment of actual postfermentation broth on EBDM process was also investigated. Simultaneous effective separation of alphaketoglutarate from the actual post-fermentation broth (after pre-treatment procedure) and conversion to alpha-ketoglutaric acid form were carried out. The results presented in this paper indicate that the applied EDBM process allows almost total removal of alpha-ketoglutarate from actual post-fermentation broth with high current efficiency (64 %) and low energy consumption (1.1 kW h/kg). Furthermore, the low initial pH (2.4-2.7) of diluate solution inhibits the migration of lactate and acetate through the anion exchange membrane and reduces the scaling phenomena. Preliminary costs analysis of the electrodialytic recovery of AKG from fermentation broth (including the energy as well as fixed cost) showed that the total fixed cost per 1 kg of AKG was low and about 1.2$.