Down-Processing of 1,3-Propanediol

Recovery and purification of 1,3-PD from complex and dilute fermentation broth meet severe challenges, which is mainly attributed to its low volatility, great affinity for water, and the presence of residual glycerol, macromolecules (e.g., proteins, nucleic acids, polysaccharides), salts, and some by-products (e.g., 2,3-BD, ethanol, acetate, lactate, succinate) (Xiu and Zeng, 2008). This becomes the bottleneck of the commercialization of 1,3-PD from renewable resources. 

Considerable progress has been made in the separation of 1,3-PD, including evaporation, distillation, membrane filtration, pervaporation, molecular sieves, chromatography, liquid-liquid extraction, reactive extraction, and salting-out extraction (SOE). However, all these methods have some limitations. 

Electrodialysis membrane has been employed for desalination before evaporation (Gong et al., 2004 Wu et al 2011). About 90% of the organic acid salts were successMly removed by electrodialysis. However, the loss of 1,3-PD due to diffusion, membrane fouling, high investment, and operational cost make this process undesirable. 

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