Cleaner production and downstream processing of bio-based 2,3-butanediol: A review

Bio-based 2,3-butanediol (2,3-BD) has attracted more and more attention due to the relatively high cost of its petro-based production and the emerging economic advantages of bio-based 2,3-BD production processes. 2,3-BD has wide applications in the chemical, food, cosmetics, agriculture, pharmaceutical, and aerospace area, especially producing the monomer of the polybutadiene synthetic rubber. Thus, recent advances on the properties, production, and application of bio-based 2, 3-BD were critically reviewed. With great efforts in the screening of 2, 3-BD producing bacteria and factors affecting the productivity of 2,3-BD, the concentration of 2,3-BD in the fermentation broth can be greater than 150 g/L, even up to 178 g/L. On the other hand, the high boiling point and high hydrophilicity of 2,3-BD and the complex composition and low product concentration in the fermentation broth made the conventional distillation extremely challenging for the industrial production of 2.3-BD by the biological method. It is crucial to develop an efficient and low-cost separation process for 2,3-BD. The recent advances in the development of separation processes for the in-situ or ex-situ recovery of 2, 3-BD from the fermentation broth or aqueous solutions are thoroughly reviewed. Some emerging separation technologies, including vacuum evaporation/distillation, solvent extraction, reactive extraction, adsorption, salting-out extraction, salting-out, sugaring-out extraction, and pervaporation, were developed to simplify the separation process. After the techno-economic evaluation of the hybrid process with the emerging techniques, it is demonstrated that the novel methods can greatly reduce energy consumption(up to 54.8%) and downstream separation cost(25.8–61.2%).