Clostridium pasteurianum forms acetic and butyric acids in an initial growth phase, which is a typical feature of clostridial acetone-butanol fermentation where an initial accumulation of acids is followed by production of solvents 1-butanol, acetone and ethanol. The initiation of the solvent production coupled with endospore formation leads to decrease of cell-wall thickness; thinner cell wall is more resistant against solvents and dyes. These changes can be observed by the method based on adaptation of Gram staining. The cell wall of G+ bacteria allows the entry of hexidium iodide and rhodamine 123, whereas the outer membrane of G- bacteria does not allow the uptake and therefore G+ bacteria are stained with higher fluorescence intensity than G- bacteria. The ratio of fluorescence intensity (FI) to forward scatter (FSC) was determined to correspond to G+ bacteria when clostridia were producing less solvents. The significant drop of the ratio FI to FSC to the level corresponding to G- bacteria is detected after initiation of solvent production.

Department of Fermentation Chemistry and Bioengineering Institute of Chemical Technology Prague Prague

6th International Symposium of Anaerobic Microbiology (ISAM 2009) held in Liblice (Czech Republic), 18 - 20 June 2009

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