Valorization of crude glycerol from the biodiesel industry to 1,3‐propanediol by Clostridium butyricum DSM 10702: Influence of pretreatment with ion exchange resins

1,3-propanediol (1,3-PD) was biosynthesised with Clostridium butyricum DSM 10702 using crude glycerol as a substrate. The batch fermentation of crude glycerol (70 g/L) without previous purification produced a significant concentration of 1,3-propanediol (35.9 g/L, Y1,3-PD/S = 0.51 g 1,3-PD/g glycerol) at 37 °C and pH 6.5. The maximum tolerance of C. butyricum DSM 10702 to the inhibitory effect of the substrate was 70 g/L. In fed-batch fermentation, the 1,3-PD concentration was similar: 36.1 g/L. Pretreatment processes for biodiesel-based crude glycerol based on ion exchange resins (Lewatit S8528 and Lewatit GF series) were evaluated. For the two different fermentation modes studied (batch and fed-batch systems), the pretreatment slightly improved the results reached in fermentations carried out with untreated crude glycerol, especially 1,3-PD productivity which increased from 0.52 g/(L · h) for crude glycerol to 0.99 g/(L · h) for pretreated glycerol. In batch fermentation of glycerol pretreated with a Lewatit S8528, a concentration of 41.4 g/L of 1,3-PD was reached, similar to that found in fed-batch fermentation.