Recent advances in butanol production by acetone-butanol-ethanol (ABE) fermentation

Butanol can be produced from renewable sources via the acetone-butanol-ethanol (ABE) fermentation route to create biobutanol or from fossil fuel to create petrobutanol. Despite the similar chemical properties of these two forms of butanol, the market penetration of biobutanol is still hindered due to its higher production costs compared to those for petrobutanol. This review article traces the history of the butanol industry and discusses recent advances in butanol production by ABE fermentation, with several novel approaches being highlighted. These approaches include searching for abundant and inexpensive substrates and optimising upstream and downstream processes. As butanol production by ABE fermentation consists of several critical stages, this review article divides the whole process into five significant steps: (1) feedstock selection, (2) upstream, (3) midstream, (4) downstream and (5) final products. Recent progress involving all stages along with their challenges and potential research routes are summarised. Recent progresses in the direct use of ABE as a biofuel are also reviewed in brief. Low butanol yield and end-product toxicity remain the major drawbacks of a typical butanol production by ABE fermentation. For successful biobutanol production, a number of critical issues should be considered. These include the development of clostridial and non-clostridial strains as well as innovative in-situ recovery methods integrated with the ABE fermentation process. Finally, future research direction of butanol production by ABE fermentation is presented in the last section of this article.