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

Abstract

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.