Co-fermentation of glycerol and sugars by Clostridium beijerinckii: Enhancing the biosynthesis of 1,3-propanediol

Sustainable biosynthesis of 1,3-propanediol (1,3-PD) from glycerol is limited by the need for an efficient strain, high cost of the fermentation medium, and substrate inhibition. To address these limitations, the optimal operational conditions for C. beijerinckii CCIC 22954 were determined using a single factor optimization approach. Batch fermentation was done using a cheap medium containing 7.5 g/L of corn steep liquor instead of yeast extract and glycerol, which led to 14.3 g/L of 1,3-PD with a 0.48 g/g yield and 0.3 g/L.h productivity. To further increase the yield, the co-fermentation of glycerol and individual sugars (arabinose, glucose, sucrose, and xylose) was studied. A maximum 23.3 g/L of 1,3-PD was obtained from the co-fermentation of glycerol (30 g/L) and glucose (10 g/L), with 0.78 g/g yield and 0.49 g/L.h productivity. These results showed the feasibility of cofermentation technology in the sustainable biomanufacturing of 1,3-PD by generally recognized as safe (GRAS), C. beijerinckii.