Isolation of mesophilic solvent-producing clostridia from Colombian sources: physiological characterization, solvent production and polysaccharide hydrolysis

One hundred and seventy-eight new butanol-acetone producing bacteria relate d to saccharolytic clostridia were isolated from agricultural sources in Co lombia and their fermentation potential was evaluated. Thirteen isolates pr oduced more total solvents from glucose than Clostridium acetobutylicum ATC C 824. The isolates with the highest single solvent production were IBUN 12 5C and IBUN 18A with 0.46 mol butanol and 0.96 mol ethanol formed from 1 mo l glucose, yielding 25.2 and 29.1 g 1(-1) total solvents, respectively, whi ch is close to the maximum values described to date. Most of the new isolat es produced exoenzymes for the hydrolysis of starch, carboxymethyl cellulos e, xylan, polygalacturonic acid, inulin and chitosan. Together with the hig h efficiency of solvent production, these hydrolytic isolates may be useful for the direct fermentation of biomass. According to their physiological p rofile, the most solvent-productive isolates could be classified as strains of C. acetobutylicum, Clostridium beijerinckii, and Clostridium NCP262. (C ) 2000 Elsevier Science B.V. All rights reserved.