Acetic acid production using xylose and corn steep liquor by thermoaceticum strain

Acetic acid production from xylose by Clostridium thermoaceticum (ATCC 49707) requires adaptation of the strain to xylose medium. It preferentially consumes xylose over glucose using a mixture of glucose and xylose as a carbon source. The initial concentration of xylose in the medium affects the final concentration and the yield of acetic acid. Batch fermentation of 20 g/L of xylose with 5 g/L of yeast extract (YE) as a nitrogen source results a maximum acetate concentration of 15.2 g/L and yield of 0.76 g acid/g xylose. Corn steep liquor (CSL) is a good substitute for yeast. extract and results in similar fermentation profiles. The organism consumes fructose, xylose and glucose when from a mixture of sugars in batch fermentation. Arabinose, man-nose and galactose are consumed only slightly. This organism loses viability upon fed-batch operation even with supplementation of all the required nutrients. In fed-batch fermentation with CSL supplementation, D-xylulose (an intermediate in the xylose metabolic pathway) accumulates in large quantities.