Review on the Downstream Purification of the Biologically Produced 1,3-Propanediol

Abstract

The blooming of biodiesel, oleochemical, and agricultural industries gives rise to the spiking availability of fermentable carbon sources for 1,3-propanediol (1,3-PDO) production from their by-products. Despite the availability of such sustainable feedstocks, the downstream process of bio-based 1,3-PDO which contributed to 50-70% of the total production cost remained a key bottleneck towards economic viability. Judging from the complex and aqueous content of the fermented broth, low volatility, and polar nature of 1,3-PDO, one-step refining is unachievable to obtain highly purified 1,3-PDO as required by the market. Herein, the purification of fermented 1,3-PDO involves multiple steps which include solids removal, flocculation, desalination, recovery, and final thermal separation step. This article gives an overview of the downstream processes with a main focus on dissecting resin adsorption and ion-exchange chromatography as the main polishing steps. Despite high efficiency, chromatography methods are impeded by their complicated procedures and the involvement of expensive resins, which are among the challenges to commercialization.