Eco‐efficient recovery of non‐volatile products from fermentation broth: aliphatic diols

Fermentation can be used to obtain a wide variety of valuable high‐boiling components. Among these components, microorganisms can produce aliphatic diols (e.g. propanediols, butanediols, etc.) in significant concentrations (e.g. 5–15 wt.%). Nonetheless, the high boiling points of these components, presence of microorganisms, and formation of by‐products complicate recovery after fermentation. Hence, this perspective offers valuable insights into downstream processing options. A novel methodology was developed for recovering high‐boiling components from dilute aqueous solutions, whereby both light and heavy impurities are present. The main steps in the proposed methodology are heat pump‐assisted preconcentration and final purification in a dividing‐wall column. These steps allow effective separation of high‐purity product from water, light and heavy impurities. Furthermore, processes for recovery of 1,3‐propanediol, 2,3‐, 1,4‐ and 1,3‐butanediol, designed according to the proposed methodology, were compared. Downstream processing performance is mainly determined by the product concentration in the fermentation broth, but is also influenced by the amount of impurities in the broth.