Upgraded medium composition highlights the relevance of iron sulfate for 1,3-propanediol production by a Clostridium beijerinckii strain

Nine medium compositions for obtaining 1,3-PDO from glycerol fermentation by Clostridium beijerinckii Br21 were compared. A partial least squares (PLS) regression analysis revealed that K2HPO4, yeast extract, FeSO4.7H(2)O, MgSO4.7H(2)O, and cysteine affected 1,3-PDO production positively. The three first compounds were investigated. By maintaining the K2HPO(4) concentration at 5 g.L-1 and enhancing yeast extract in the selected medium from 0.5 to 1.0 g.L-1, 1,3PDO concentration increased by 16.2%. A central composite rotatable design (CCRD) revealed that glycerol at 370.7 mmol.L-1 and FeSO4.7H(2)O at 55 mg.L-1 increased 1,3-PDO concentration from 34.9 to 52.7 mmol.L-1. Replacement of FeSO4.7H(2)O with other iron salts revealed that FeSO4.7H(2)O was the most suitable for obtaining 1,3-PDO. The results highlight the importance of iron sulfate for glycerol fermentation to 1,3-PDO by a C. beijerinckii strain.