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Lepiz-Aguilar L.,University of Costa Rica | Rodriguez-Rodriguez C.E.,Food and Water Microbiology Laboratory | Arias M.L.,Food and Water Microbiology Laboratory
Journal of Microbiology and Biotechnology | Year: 2013

Cassava constitutes an abundant substrate in tropical regions. The production of butanol in ABE fermentation by Clostridium beijerinckii BA101 using cassava flour (CF) was scaled-up to bioreactor level (5 L). Optimized fermentation conditions were applied; that is, 40°C, 60 g/l CF, and enzymatic pretreatment of the substrate. The batch fermentation profile presented an acidogenic phase for the first 24 h and a solventogenic phase afterwards. An average of 37.01 g/l ABE was produced after 83 h, with a productivity of 0.446 g/l/h. Butanol production was 25.71 g/l with a productivity of 0.310 g/l/h, high or similar to analogous batch processes described for other substrates. Solvent separation by different combinations of fractioned and azeotropic distillation and liquid-liquid separation were assessed to evaluate energetic and economic costs in downstream processing. Results suggest that the use of cassava as a substrate in ABE fermentation could be a cost-effective way of producing butanol in tropical regions. © 2013 by The Korean Society for Microbiology and Biotechnology. Source


Lepiz-Aguilar L.,University of Costa Rica | Rodriguez-Rodriguez C.E.,Food and Water Microbiology Laboratory | Rodriguez-Rodriguez C.E.,Autonomous University of Barcelona | Arias M.L.,Food and Water Microbiology Laboratory | Ulate W.,University of Costa Rica
World Journal of Microbiology and Biotechnology | Year: 2011

Cassava flour (CF), a cost-effective source of starch, was employed as a substrate for successful acetone-butanol-ethanol (ABE) production by batch-fermentation with Clostridium beijerinckii. The effect of temperature, initial concentration of CF and chemical/enzymatic hydrolysis were studied in a 2 3 factorial design. Results revealed that temperature and initial concentration of substrate exert a significant effect on ABE production, as well as interactions of temperature with the other variables. Solvent production was maximized when working at 40°C, 60 g l -1 CF and enzymatic pretreatment. An average of 31.38 g l -1 ABE was produced after 96 h, with a productivity of 0.33 g l -1 h -1. A posterior randomized block design (3 × 2) showed that enzymatic hydrolysis (with saccharification periods of 6 h at 60°C) enhances both reducing sugar and solvent production if compared to chemical pretreatments. Average ABE production in this case was 27. 28 g l -1, with a productivity of 0.28 g l -1 h -1. Results suggest that CF may be a suitable substrate for industrial ABE production. © 2010 Springer Science+Business Media B.V. Source

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