P Galzy

Ecole Nationale Supérieure de Chimie de Montpellier, Montpelhièr, Languedoc-Roussillon, France

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Publications (291)356.4 Total impact

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    ABSTRACT: The exocellular enzyme β-glucosidase of Candida molischiana was studied. This strain is able to ferment soluble cellodextrins. The enzyme was partially purified by ion-exchange chromatography and gel filtration. The molecular weight of this enzyme was 120 000; its optimum pH was between 4 and 4.5 and its optimum temperature was 60 °C. This enzyme was active against different soluble glucosides and was inhibited by p-chloromercuribenzoate, gluconolactone, and glucose. A "glucosyltransferase" activity appeared in the presence of ethanol. The biosynthesis of the enzyme was constitutive but repressed by glucose.
    Canadian Journal of Biochemistry and Cell Biology. 04/2011; 63(11):1160-1166.
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    ABSTRACT: During the process of sporulation, the oxidation rate of exogenous carbon source, acetic acid, is high during a period lasting from 1 to 4 h. Then it falls rapidly and the metabolism of acetic acid seems to be deflected. Endogenous oxidation rate rises rapidly at the beginning of the process and reaches its maximum after a 12- to 16-h contact with the sporulation medium. Then it falls regularly.
    Canadian Journal of Microbiology 02/2011; 17(9):1179-1184. · 1.20 Impact Factor
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    ABSTRACT: Mutants of Brevibacterium sp. R312 were isolated for the production of adipic acid from adiponitrile. One mutant (Ad) with a modified cell wall showed activity against adipamide 3 times greater than the wild type. Another mutant (ACV2) derived from the Ad strain had 30 times more activity on cyano-5-valeric acid, and 7 times more on adipamide, than the wild type. The presence of an amidase acting on amide intermediates in the hydrolysis of dinitriles to organic acids was demonstrated in these mutants.
    Canadian Journal of Microbiology 02/2011; 39(5):524-528. · 1.20 Impact Factor
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    ABSTRACT: Through mutagenesis by nitrous acid a mutant was obtained which differed from the wild strain by two independent characters. The mutant gave smooth colonies on a solid medium containing lactic acid; the wild type yielded rough colonies on the same medium. The smooth colony character was unstable during vegetative growth. The mutant was homothallic. This character was stable during vegetative growth but it was not segregated through meïosis. This mutation inducing homothallism is not controlled by a gene.
    Canadian Journal of Microbiology 02/2011; 17(3):425-428. · 1.20 Impact Factor
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    ABSTRACT: The effect of different compounds on the enzymic action of the nitrile-hydratase used for the bioconversion of nitriles was studied. An excess of acrylonitrile as a substrate was shown to inhibit the activity of the enzyme. This inhibition occurred only at relatively high substrate concentrations (0.2 mol/l or more). The nitrile bioconversion products (acrylamide, propionamide) and their structural analogues (acrylic acid, thioacetamide) were shown to inhibit the enzyme competitively. The most important inhibition found was that of cyanide (Ki= 0.004 mol/l), a break down product of some nitriles. By using an acetamidase-negative mutant, amides were shown to inhibit biosynthesis of nitrile-hydratase. An identical result was obtained with thioacetamide, a non-substrate compound for acetamidase. This compound repressed the biosynthesis of nitrile-hydratase by both the wild type and the acetamidase-negative mutant to the same extent.
    Journal of Applied Microbiology 03/2008; 57(1):183 - 190. · 2.20 Impact Factor
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    ABSTRACT: Five different Micrococcus spp. were isolated from the surface of Roquefort cheese: M. roseus, M. sedentarius, M. lylae, M. luteus and M. varians. During culture on synthetic medium these bacteria produced acetic acid as the main volatile fatty acid and propanol as the main alcohol. On a complex medium these isolates synthesized additional volatile fatty acids. Studies were made of the effect of pH, of water activity adjusted with sodium chloride or sorbitol, and of temperature on growth rates. All five isolates were inhibited at a pH lower than 5.5 and grew at temperatures from 4° to 44°C; they were halotolerant and multiplied at NaCl concentrations up to 20%, corresponding to a water activity of 0.884.
    Journal of Applied Microbiology 03/2008; 76(6):546 - 552. · 2.20 Impact Factor
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    ABSTRACT: An alcohol dehydrogenase HUADHII was purified 43.2-fold from Hanseniaspora uvarum K5. The enzyme was trimeric with subunits of mol. wt 42 kDa. The N-terminal amino acid sequence of HUADHII has between 45 and 75% identity with part of the sequence of isoenzymes related to group I from Saccharomyces cerevisiae and Kluyveromyces lactis. C2–C4 alcohols and aldehydes were the preferred substrates. The presence of an’’double bond increased the enzyme activity both for alcohols and aldehydes. It was significantly inhibited by metal-binding agents and thiol reagents. Kinetic studies suggested that HUADHII catalyses the oxidation of ethanol by a random sequential mechanism. It appears that HUADHII, a cytoplasmic fermentative enzyme, is structurally and functionally similar to members of the group I alcohol dehydrogenases.
    Journal of Applied Microbiology 03/2008; 79(1):79 - 86. · 2.20 Impact Factor
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    ABSTRACT: A yeast strain isolated in the laboratory was studied and classified as a Zygosaccharomyces bailii. Both intracellular and extracellular β-glucosidases of this yeast were purified by ion-exchange chromatography, gel filtration and hydroxylapatite (only for the intracellular enzyme). The tetrameric structure of the two β-glucosidases was determined following treatment of the purified enzyme with dodecyl sulphate. The intracellular β-glucosidase exhibited optimum activity at 65°C and pH 5.5. The extracellular enzyme exhibited optimum catalytic activity at 55°C and pH 5. The molecular mass of purified intracellular and extracellular β-glucosidases, estimated by gel filtration, was 440 and 360 kDa, respectively. Both enzymes are active against glycosides with (1 → 4)-β, (1 → 6)-β and (1 → 4)- linkage configuration. The intracellular enzyme possesses (1 → 6)--arabinofuranosidase activity and extracellular enzyme (1 → 6)--rhamno-pyranosidase activity. The two β-glucosidases are competitively inhibited by glucose and by D-gluconic-acid-lactone and a slight glucosyl transferase activity is observed in the presence of ethanol. Since the glycosides present in wine and fruit juices represent a potential source of aromatic flavour, the possible use of the yeast β-glucosidases for the liberation of the bound aroma is discussed.
    Journal of Applied Microbiology 03/2008; 78(3):270 - 280. · 2.20 Impact Factor
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    ABSTRACT: The β-glucosidase of Hanseniaspora vineae was purified by ion-exchange chromatography and gel filtration. Its molecular weight was 295000 PT 15000, its optimum pH was between 6 and 6–5, and its optimum temperature was 55°C. The enzyme was active against different soluble glucosides with β(1–2), β(1–3), β(1–4), β(1–6) and even aP(1–4) configurations. A glucosyltransferase activity appeared in the presence of ethanol. The enzyme was constitutive but its synthesis was repressed by glucose.
    Journal of Applied Microbiology 03/2008; 66(4):271 - 279. · 2.20 Impact Factor
  • Hélène Boze, Guy Moulin, Pierre Galzy
    03/2008: pages 166 - 220; , ISBN: 9783527620920
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    ABSTRACT: Flavor compounds synthesis by biotechnological processes today plays an increasing role in the food industry. This is the result of scientific advances in biological processes, making use of microorganisms or enzymes as an alternative to chemical synthesis, combined with recent developments in analytical techniques, such as HPLC, gas chromatography (GC), IR, or mass spectrometry. The study of the aromatic potential of some fruits, such as passion fruit, apple, and grapes as well as their fermentation products (juice, wine), has revealed that in addition to a free fraction of volatile terpenols, there exist naturally nonodorous and nonvolatile aroma precursors, which represent an important source of fragant compounds (1–3). An important part of this aromatic pool is composed of terpenylglycosides, whose terpenic residue is β-glucosidically bound to disaccharide glucosides. The sugar moieties have been identified as β-D-glucose, 6-O-α-L-rhamnopyranosyl-β-D-glucopyranose, 6-O-α-L-arabinofuranosyl-β-D-glucopyranose, and 6-O-β-D-apiofuranosyl-β-D-glucopyranose. The aglycon part is frequently formed of terpenols, principally linalool, nerol, and geraniol with in some cases linalool oxides, terpenes diols, and triols (4–6). The presence of a β-glucosidic bond between the terpenic residue and the saccharide has suggested a possible liberation of terpenic molecules by enzymatic catalysis using a β-glucosidase. Such an enzyme has a great potential in the wine and fruit juices industry, since the quantities of bound monoterpenes in most fruit juices and wines are usually relatively high.
    02/2008: pages 323-331;
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    ABSTRACT: Biotransformation of Lmalic acid into Llactic acid was studied in a fluidised bed reactor using cells of Lactobacillus sp. 89 and Leuconostoc oenos ATCC 23278 immobilised in a calcium alginate matrix. The reactor was used in a batch or a continuous manner under a non-oxidising atmosphere. It was shown that 3 mm diameter beads loaded with 6 and 30 mg dry matter per gram of gel were the best operating conditions for Leuconostoc and Lactobacillus respectively. The optimal working conditions were as follows: pH = 3.0–5.0, temperature = 30°C for Lactobacillus and pH = 3.0, temperature = 25°C for Leuconostoc. No inhibition due to lactic acid was observed and the internal diffusional effects were negligible. The short catalyst life that was initially observed with both strains resulted from a depletion in NAD and Mn2+, two basic cofactors for malolactic enzymes. To prevent this detrimental effect, a regeneration process for biocatalyst was proposed.
    Journal of Chemical Technology & Biotechnology 04/2007; 51(1):81 - 95. · 2.50 Impact Factor
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    ABSTRACT: The action of pH on respiratory metabolism, evolution of carbohydrate, and sporulation are studied. Experiments have been made with cells harvested during the early log phase or during the late log phase.Carbohydrate reserves are synthesized from the acetate only when there is sporulation.At the end of the sporulation, glycogen is very abundant in asci. Physiological state, pH, and sporulation are discussed.
    Journal of Basic Microbiology 01/2007; 13(2):99-106. · 1.20 Impact Factor
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    ABSTRACT: Le métabolisme respiratoire de Kluyveromyces fragilis présente des differénces importantes avec celui de Saccharomyces cerevisiae.L'effect glucose qui est très important chez S. cerevisiae (Ephrussi 1966) est inexistant chez les Kluyveromyces. La concentration en glucose n'a pratiquement pas d'influence sur l'activité respiratoire.Le métabolisme fermentaire des Kluyveromyces est moins actif que celui des Saccharomyces. Il est sensible à l'action inhibitrice de l'air. Cependant l'effet Pasteur est moins important que chez S. cerevisiae.Le métabolisme respiratoire est généralement plus actif que le métabolisme fermentaire (Q) Chez les Kluyveromyces.
    Journal of Basic Microbiology 01/2007; 13(3):193-199. · 1.20 Impact Factor
  • G. Moulin, P. Galzy
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    ABSTRACT: The synthesis of amylolytic enzymes by Pichia burtonii strain CBS 6141 requires the presence of etarch, maltose, and saccharose. Glucose exerts a strong repression which completely inhibited snzyme induction.Dans un précédent article (MOULIN et GALZY 1978) nous avons décrit les propriétés générales d'une α amylase présente dans la paroi de Pichia burtoniiBOIDIN. Nous étudierons ici quelques aspects de la régulation de la biosynthèse de cet enzyme.
    Journal of Basic Microbiology 01/2007; 18(5):329-333. · 1.20 Impact Factor
  • Journal of Basic Microbiology 01/2007; 24(3):151-159. · 1.20 Impact Factor
  • G. Pons, J. Guiraud, P. Galzy
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    ABSTRACT: Candida utilis has a strong fermentative metabolism, that is more important than respiratory activity. This species is characterized for a strong PASTEUR effect and for absence of glucose effect.
    Journal of Basic Microbiology 01/2007; 16(5):377-383. · 1.20 Impact Factor
  • G. Moulin, P. Galzy
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    ABSTRACT: La présence d'une α amylase pariétale de Pichia burtoniiBOIDIN est étudiée. Deux formes ont été trouvées. Une fraction facilement extractible au moyen d'un tampon phosphate 20 mM et une fraction fortement liée à la paroi. Le pH optimum est 6,2.L'activité enzymatique n'est pas modifiée par les ions K+, Na+, NH4+. Elle est fortement inhibée par EDTA et les métaux lourds.
    Journal of Basic Microbiology 01/2007; 18(4):269-274. · 1.20 Impact Factor
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    ABSTRACT: The purification of the lipase from Candida curvata CBS 570 was achieved steps. Its optimum pH is 6 and its optimum temperature range is Iff C to 60°C. This enzyme is thermoresistant and only loses 20% of its activity when heated at 50°C during 30 minutes. Its activation energy is 144 kcal/mole and its inactivation energy 22 kcal/mole. Its molecular weight was determined to be 195000. EDTA, p-chloromercuri benzoate, N-ethyl- and iodoacetamide have no influence on the activity of this enzyme, whereas Cu++ and Zn++ show strong inhibitory effects. The lipase activity is induced by the presence of triglycerides and inhibited by the presence of glucose. This enzyme strongly attacks triolein and trilinolein molecules, however it only hydrolyzes a little tristearin and trilinolenin.Reinigung und Charakterisierung einer Lipase aus Candida curvata Lodder und Kreger-van Rij CBS 570Die Reinigung einer Lipase aus Candida curvata CBS 570 wurde in drei Schritten erreicht. Ihr optimaler pH-Wert betrgt 6 und ihre optimale Temperatur liegt zwischen 50° und 60°C. Dieses Enzym ist thermoresistent und verliert nur 20% seiner Aktivitt, wenn as 30 Minuten lang auf 50°C erhitzt wird. Seine Aktivierungsenergie betrgt 14.4 kcal/Mol und seine Inaktivierungsenergie 22 kcal/Mol. Sein Molekulargewicht wurde mit 195000 bestimmt. EDTA, p-Chloromercuribenzoat, N-Athylmaleimid und Jodacetamid haben keinen Einfluß auf die Aktivitt dieses Enzyms, whrend Cu++ und Zn++ starke Hemmwirkungen zeigen. Die Lipaseaktivitt wird durch die Anwesenheit von Triglyceriden induziert und durch Glukoseanwesenheit gehemmt. Dieses Enzym hydrolysiert Triolein- und Trilinoleinmoleküle sehr stark, Tristearin und Trilinolenin jedoch nur geringfügig.
    Chemische Revue über die Fett- und Harz-Industrie 10/2006; 87(5):181 - 185.
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    ABSTRACT: The exocellular β-glucosidases of Candida molischiana and Candida wickerhamii are able to hydrolyse geranyl, neryl, citronellyl, linalyl and α-terpinyl-β-D-glucopyranosides. The nature of the aglycone residue greatly affects the rate of hydrolysis. Glucosides with a tertiary alcohol as aglycone residue are more slowly hydrolysed than those with a primary alcohol. The β-glucosidase from C molischiana is also able to hydrolse α-L-arabinofuranosides. This results in the release of monoterpenols from a glycoside extract from grape juice.
    Journal of the Science of Food and Agriculture 09/2006; 50(4):499 - 506. · 1.76 Impact Factor

Publication Stats

2k Citations
356.40 Total Impact Points

Institutions

  • 1973–2008
    • Ecole Nationale Supérieure de Chimie de Montpellier
      Montpelhièr, Languedoc-Roussillon, France
  • 1974–2007
    • Université Montpellier 2 Sciences et Techniques
      • Département des Sciences et Technologies des Industries Alimentaires (STIA)
      Montpelhièr, Languedoc-Roussillon, France
  • 1971–2007
    • French National Institute for Agricultural Research
      Lutetia Parisorum, Île-de-France, France
  • 1991
    • Pierre and Marie Curie University - Paris 6
      • Centre de génétique moléculaire (CGM) - FRE 3144
      Paris, Ile-de-France, France