Direct fermentation of sweet sorghum juice by Clostridium acetobutylicum and Clostridium tetanomorphum to produce bio-butanol and organic acids

Single- and co-culture clostridial fermentation was conducted to obtain organic alcohols and acids from sweet sorghum juice as a low cost feedstock. Different inoculum concentrations of single cultures (3, 5, 10 v/v %) as well as different ratios of C. acetobutylicum to C. tetanomorphum (3:10, 10:3, 6.5:6.5, 3:3, and 10:10 v/v %, respectively) were utilized for the fermentation. The maximum butanol concentration of 6.49 g/L was obtained after 96 h fermentation with 10 % v/v C. acetobutylicum as a single culture. The fermentation with 10% v/v C. tetanomorphum resulted in more than 5 g/l butyric acid production. Major organic acid concentration (lactic acid) of 2.7 g/L was produced when an inoculum ratio of 6.5: 6.5 %v/v C. acetobutylicum to C. tetanomorphum was used

n-Butanol derived from biochemical and chemical routes: A review

Traditionally, bio-butanol is produced with the ABE (Acetone Butanol Ethanol) process using Clostridium species to ferment sugars from biomass. However, the route is associated with some disadvantages such as low butanol yield and by-product formation (acetone and ethanol). On the other hand, butanol can be directly produced from ethanol through aldol condensation over metal oxides/ hydroxyapatite catalysts. This paper suggests that the chemical conversion route is more preferable than the ABE process, because the reaction proceeds more quickly compared to the fermentation route and fewer steps are required to get to the product