Developing a coculture for enhanced butanol production by Clostridium beijerinckii and Saccharomyces cerevisiae

Developing a coculture using different microorganisms to produce biofuels by taking advantages of their specific metabolic capacities is of great interest. In this study, a novel coculture of a butanol-resistant Clostridium beijerinckii F-6 and S. cerevisiae was proposed and experimentally achieved. Results showed that the butanol concentration and productivity reached 12.75 g/L and 0.454 g/L^• h in the coculture when S. cerevisiae was added at 0. 02 g/L after 12 h fermentation of C. beijerinckii F-6 at initial pH of 7.0, which were 203% and 155% higher, respectively, than the monoculture without S. cerevisiae addition. Moreover, the glucose consumption, butanol ratio and energy conversion efficiency reached 47.23 g/L, 0.75, and 62.47% respectively, which were 12.7%, 4.2%, and 177.4% higher than those in the control. The measurements of amino acids during fermentation demonstrated an adequate addition of yeast could promote butanol synthesis by accelerating the accumulation of aromatic and aspartic acids.