Recovery of biobased 2,3-butanediol from fermentation broths by liquid-phase adsorption onto phenylboronate polymers

Abstract

In recent years, 2,3-butanediol (BDO) has been recognized as a valuable platform molecule suitable for production of bulk and fine chemicals. BDO can be efficiently produced biotechnologically in high titer. Recovery of high-boiling and highly polar BDO from the fermentation broths presents the major challenge. In this study, we propose adsorption of BDO onto polymers bearing phenylboronate groups as a method for selective and efficient recovery. We optimized the adsorption parameters, such as NaOH concentration and the dilution factor, using solutions of commercially available BDO. Under the optimized conditions, nearly quantitative complexation of phenylboronates occurs, which corresponds to a loading of 250 mgBDO gPolymer−1. Desorption of BDO into acidic and neutral solutions was efficient. Most importantly, an 80%EtOH/20%H2O mixture can be used to recover BDO with up to 93% desorption efficiency. Two fermentation broths obtained with Bacillus licheniformis DSM 8785 were applied for adsorption studies. The material capacities upon adsorption from the fermentation broths were as high as from the model solutions. BDO uptake from the fermentation broth was very selective, with only negligible co-adsorption of other components, such as acetoin, lactate or succinate. Utilization of the polymer in three adsorption and two desorption cycles proved recyclability of the material. 1H, 11B, and 13C MAS NMR were used to monitor the adsorption and desorption processes. This work shows a high potential of the polymers bearing phenylboronate functionalities for adsorptive recovery of BDO from fermentation broths.

Keywords

• Downstream processing
• 2,3-butanediol
• Adsorption
• Phenylboronic acid
• Functional polymers