Inhibition of Clostridium butyricum by 1,3-propanediol and diols during glycerol fermentation.
1,3-Propanediol inhibition during glycerol fermentation to 1,3-propanediol by Clostridium butyricum CNCM 1211 has been studied. The initial concentration of the 1,3-propanediol affected the growth of the bacterium more than the glycerol fermentation. mu(max) was inversely proportional to the initial concentration of 1,3-propanediol (0-65 g l(-1)). For glycerol at 20 g l(-1), the growth and fermentation were completely stopped at an initial 1,3-propanediol concentration of 65 g l(-1). However, for an initial 1,3-propanediol concentration of 50 g l(-1) and glycerol at 70 g l(-1), the final concentration (initial and produced) of 1,3-propanediol reached 83.7 g l(-1)(1.1 M), with complete consumption of the glycerol. Therefore, during the fermentation, the strain tolerated a 1,3-propanediol concentration higher than the initial inhibitory concentration (65 g l(-1)). The addition of 1,2-propanediol or 2,3-butanediol (50 g l(-1)) in the presence of glycerol (50-100 g l(-1)), showed that 2-diols reduced the mu(max) in a similar way to 1,3-propanediol. The measurement of the osmotic pressure of glycerol solutions, diols and diol/glycerol mixtures did not indicate any differences between these compounds. The hypothesis of diol inhibition was discussed. Taking into account the strain tolerance of highly concentrated 1,3-propanediol during fermentation, the fermentation processes for optimising production were considered.
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Laboratoire de Microbiologie Industrielle et Génétique des Micro-organismes, INRA, Gruissan, France.
Bories
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Moulin
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D002072:Butylene Glycols / Q000494:pharmacology; D003013:Clostridium / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media; D005285:Fermentation; D005990:Glycerol / Q000378:metabolism*; D019946:Propylene Glycol / Q000494:pharmacology; D011409:Propylene Glycols / Q000378:metabolism* / Q000494:pharmacology*
D002072:Butylene Glycols; D003470:Culture Media; D011409:Propylene Glycols; C026978:2,3-butylene glycol; C041787:1,3-propanediol; D019946:Propylene Glycol; D005990:Glycerol