Novel resin-based vacuum distillation-crystallisation method for recovery of succinic acid crystals from fermentation broths

In this paper, a novel resin-based crystallisation method was developed for the recovery of succinic acid (SA) crystals from fermentation broths (FB) using Actinobacillus succinogenes. Direct crystallisation of synthetic fermentation broths was firstly investigated and the results indicated that the synthetic fermentation broth consisting of a mixture of organic acids (in the free acid form rather than in the salt form) could significantly benefit in succinic acid recovery. Therefore, a commercially available cation-exchange resin Amberlite IR 120H was employed to convert the fermentation end-products such as succinate, formate, acetate and pyruvate from the salt form into the free acid form. Then, succinic acid was selectively separated from the acid mixture by vacuum evaporation and crystallisation. Highly purified SA crystals were successfully recovered from both synthetic and real fermentation broths using this method. A higher SA crystal purity (99%) and yield (89.5%) were obtained in the direct crystallisation method using an ion-exchange resin as compared to the direct acid addition method (46% and 35%, respectively). The work presented here sets the stage for the development of an efficient resin-based vacuum-distillation and crystallisation system for the recovery of succinic acid crystals from fermentation broths.