Salting-out as a Fast and Simple Method for First-Step Separation of Biobased 1,3-Propanediol

Abstract

The cost of 1,3-propanediol (1,3-PDO) microbial production is very much dependent on the separation of 1,3-PDO from the fermentation broth. The use of byproducts as nutrient sources has significant economic and environmental advantages. This specific molecule can be produced from the fermentation of raw glycerol. Crude glycerol is a primary byproduct in the biodiesel production process, and its large surplus blocks the development of the biodiesel industry. This study focused on separating 1,3-PDO through salting-out extraction (SOE), employing ethanol and 2propanol, along with five different salts, for screening. Subsequently, an experimental design was implemented to determine optimal alcohol and salt concentrations, maximizing key variables such as the partition coefficient and recovery yield. The entire quantity of 1,3-PDO was successfully recovered in the ethanolic phase, exhibiting a selectivity of 4.87 concerning glycerol. This achievement was realized by using 39 wt % KH 2 PO 4 and 19 wt % ethanol. According to the remarkable results, salting-out extraction based on ethanol and K 2 HPO 4 can be considered as an alternative and efficient platform for separating 1,3-PDO from glycerol, selectively obtaining two compounds with a high added value.