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A Bories

Publications and source records attributed to A Bories.

9 recordsLinked to original sources
PubMed2000

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.

Butylene Glycols↗
PubMed2000

Propionic acid fermentation of glycerol and glucose by Propionibacterium acidipropionici and Propionibacterium freudenreichii ssp. shermanii.

A comparative study was carried out in anaerobic batch cultures on 20 g/l of either glycerol or glucose using two propionibacteria strains, Propionibacterium acidipropionici and Propionibacterium freudenreichii ssp. shermanii. In all cases, fermentation end-products were the same and consisted of propionic acid as the major product, acetic acid as the main by-product and two minor metabolites, n-propanol and succinic acid. Evidence was provided that greater production of propionic acid by propionibacteria was obtained with glycerol as carbon and energy sources. P. acidipropionici showed higher efficiency in glycerol conversion to propionic acid with a faster substrate consumption (0.64 g l(-1) h(-1)) and a higher propionic acid production (0.42 g l(-1) h(-1) and 0.79 mol/mol). The almost exclusive production of propionic acid from glycerol by this bacterium suggested an homopropionic tendency of this fermentation. Acetic acid final concentration was two times lower on glycerol (2 g/l) than on glucose (4 g/l) for both micro-organisms. P. freudenreichii ssp. shermanii exhibited a glycerol fermentation pattern typical of non-associated glycerol-consumption-product formation. This could indicate a particular metabolism for P. freudenreichii ssp. shermanii oriented towards the production of other specific components. These results tend to show that glycerol could be an excellent alternative to conventional carbon sources such as carbohydrates for propionic acid production.

Culture Media↗
PubMed1998

Uncoupled glycerol distribution as the origin of the accumulation of 3-hydroxypropionaldehyde during the fermentation of glycerol by enterobacter agglomerans CNCM 1210

Batch fermentation of glycerol to 1,3-propanediol (1,3PPD) by Enterobacter agglomerans CNCM 1210 showed the lethal accumulation of 3-hydroxypropionaldehyde (3-HPA) when performed under initial substrate content higher than 40 g/L. Assigned to the inhibition by the NAD/NADH ratio of the 3-HPA converting enzyme: 1,3PPD dehydrogenase, intracellular assays were conducted in an attempt to identify the metabolic mechanisms involved in the increase of that ratio. An overflow metabolism through the 1,3PPD formation pathway was established, while a catabolic limitation in the oxidative branch at the level of glyceraldehyde-3-phosphate dehydrogenase occurred. Uncoupled activities of synthesis and consumption of reducing equivalents are thus suspected to provoke the increase of the NAD/NADH ratio and the subsequent accumulation of 3-HPA. Copyright 1998 John Wiley & Sons, Inc.

Journal Article↗
PubMed1997

Sensitivity to pH, product inhibition, and inhibition by NAD+ of 1,3-propanediol dehydrogenase purified from Enterobacter agglomerans CNCM 1210.

Because of its key role in the metabolism of glycerol during fermentation, 1,3-propanediol dehydrogenase (EC 1.1.1.202) of Enterobacter agglomerans CNCM 1210 was purified to homogeneity and studied with respect to its sensitivity to pH and to nucleotide and 1,3-propanediol concentrations. Enzyme activity was optimal at pH 7.8. The enzyme was competitively inhibited by NAD+ (Ki of 0.29 mM), and 1,3-propanediol exerted a strong inhibitory effect according to a mixed-type inhibition with a Ki of 13.7 mM and an a-factor of 9.0. It is proposed that these dehydrogenase properties be extended to the dehydrogenases of Citrobacter freundii and Klebsiella pneumoniae, which exhibited numerous similar physical properties.

Alcohol Dehydrogenase↗
PubMed1997

[Subungueal exostosis of fingers in hereditary multiple exostosis. 3 cases].

INTRODUCTION: The multiple exostosis syndrome is a rare disease transmitted by autosomal dominant inheritance. Bone growth projecting outward from the long bones is observed in multiple localizations during growth. Prognosis of this benign disease is worsened by the possibility of chondrosarcoma. We report three cases of subungueal exostoses observed in children revealing hereditary exostosis. CASE REPORTS: Clinical examination evidenced progressive deformation of several fingers. In all three patients. There was subungueal tumefaction raising a fissured nail with longitudinal crests. In two cases there were also skeletal deformations. Radiograms showed multiple exostoses of the long bones in all three cases and in one a tumefaction of the scapula in addition to visualizing the subungueal exostoses. There was a family history of such manifestations in all cases. DISCUSSION: Subungueal exostosis is frequent in young adults, usually located in the large toe. These three observations were particularly interesting due to the subungueal localization during the first decade of life. Such localization are rare and usually concern several fingers.

Adolescent↗
PubMed1996

3-Hydroxypropionaldehyde, an inhibitory metabolite of glycerol fermentation to 1,3-propanediol by enterobacterial species.

Glycerol fermentation by Enterobacter agglomerans revealed that both growth and 1,3-propanediol production ceased after consumption of about 430 mM glycerol, irrespective of the initial glycerol content. This phenomenon was assigned to the production of 3-hydroxypropionaldehyde, which was identified by proton nuclear magnetic resonance and which showed a bacteriostatic effect. The accumulation during glycerol fermentation was also observed with two other enterobacterial species, i.e., Klebsiella pneumoniae and Citrobacter freundii.

Aldehydes↗
PubMed1990

Effects of sulfate on lactate and C2-, C3- volatile fatty acid anaerobic degradation by a mixed microbial culture.

The effects of sulfate on the anaerobic degradation of lactate, propionate, and acetate by a mixed bacterial culture from an anaerobic fermenter fed with wine distillery waste water were investigated. Without sulfate and with both sulfate and molybdate, lactate was rapidly consumed, and propionate and acetate were produced; whereas with sulfate alone, only acetate accumulated. Propionate oxidation was strongly accelerated by the presence of sulfate, but sulfate had no effect on acetate consumption even when methanogenesis was inhibited by chloroform. The methane production was not affected by the presence of sulfate. Counts of lactate- and propionate-oxidizing sulfate-reducing bacteria in the mixed culture gave 4.5 X 10(8) and 1.5 X 10(6) viable cells per ml, respectively. The number of lactate-oxidizing fermentative bacteria was 2.2 X 10(7) viable cells per ml, showing that sulfate-reducing bacteria outcompete fermentative bacteria for lactate in the ecosystem studied. The number of acetoclastic methanogens was 3.5 X 10(8) viable cells per ml, but only 2.5 X 10(4) sulfate reducers were counted on acetate, showing that acetotrophic methanogens completely predominated over acetate-oxidizing sulfate-reducing bacteria. The contribution of acetate as electron donor for sulfate reduction in the ecosystem studied was found to be minor.

Acetates↗
PubMedDate not supplied

Relationship between the physiology of Enterobacter agglomerans CNCM 1210 grown anaerobically on glycerol and the culture conditions.

In a preliminary study, levels of activity of enzymes involved in anaerobic glycerol catabolism by Enterobacter agglomerans grown in batch cultures regulated in a pH range of 6.5-8.0 were monitored. That study showed that activities of key enzymes of the downstream metabolism of glycerol--glyceradehyde-3-phosphate dehydrogenase (GAP-DH), lactate dehydrogenase and pyruvate formate lyase--were strongly dependent on the culture pH. To investigate the influence of pH on the physiology of the strain, E. agglomerans was grown anaerobically in a continuous culture supplied with glycerol as the sole carbon source and regulated at pH 8. A complete biochemical analysis was performed and was compared with that previously described for the continuous culture regulated at pH 7. A limitation of the glycolytic flux at the level of GAP-DH was demonstrated at high dilution rate, resulting in an overflow metabolism through the 1,3-propanediol formation pathway. Increasing the specific rate of glycerol consumption also resulted in enhanced lactate production due to limitation by the pyruvate decarboxylation step. Finally, changing the culture pH significantly modified the enzymatic profile of E. agglomerans, and it enabled the stability of the culture to be increased by preventing the accumulation in the fermentation broth of 3-hydroxypropionaldehyde, an inhibitory metabolite, when the glycerol supply was suddenly increased.

Acetyltransferases↗