Butanol production from wheat straw by simultaneous saccharification and fermentation using Clostridium beijerinckii: Part II—Fed-batch fermentation

In these studies, Clostridium beijerinckii P260 was used to produce butanol (acetone–butanol–ethanol, or ABE) from wheat straw (WS) hydrolysate in a fed-batch reactor. It has been demonstrated that simultaneous hydrolysis of WS to achieve 100% hydrolysis to simple sugars (to the extent achievable under present conditions) and fermentation to butanol is possible. In addition to WS, the reactor was fed with a sugar solution containing glucose, xylose, arabinose, galactose, and mannose. The culture utilized all of the above sugars. It was noticed that near the end of fermentation (286–533 h), the culture had difficulties utilizing xylose. As a result of supplemental sugar feed to the reactor, ABE productivity was improved by 16% as compared with previous studies. In our previous experiment on simultaneous saccharification of WS and fermentation to butanol, a productivity of 0.31 g L−1 h−1 was observed, while in the present studies a productivity of 0.36 g L−1 h−1 was observed. It should be noted that a productivity of 0.77 g L−1 h−1 was observed when the culture was highly active. The fed-batch fermentation was operated for 533 h. It should be noted that C. beijerinckii P260 can be used to produce butanol from WS in integrated fermentations.