The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Laurent Dufosse - One of the best experts on this subject based on the ideXlab platform.
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In Situ Detoxification of the Fermentation Medium during γ‐Decalactone Production with the Yeast Sporidiobolus salmonicolor
Biotechnology progress, 1999Co-Authors: Laurent Dufosse, Alain Latrasse, Gilles Feron, I. Souchon, H. E. SpinnlerAbstract:gamma-Decalactone (gamma-C10) is known to be highly toxic for the microorganims used for its production. In this work, three techniques were studied in order to overcome this toxicity during a bioconversion process using ricinoleic acid as precursor of the lactone: in situ trapping in oily phases, in porous hydrophobic sorbents and in beta-cyclodextrins. Oily phases added to the media (olive, Miglyol, tributyrin, and paraffin) had a protective effect on Sp. salmonicolor, and they improved the lactone production. beta-cyclodextrins, which have a hydrophobic cavity that can trap molecules such as gamma-C10, have been used to protect the yeasts. The results showed insufficient preservation of cell viability. Some sorbents (activated carbon and polystyrene-based sorbents) were successfully tested during bioconversion. In all cases viability exceeded the reference one. Nevertheless the aroma production was 30% lower than the reference. All of these solutions led to some enhancement of the cell viability during bioconversion of methyl ricinoleate to gamma-C10. For improvement of the lactone production, the oil trapping method seemed to be the best with the experimental conditions tested.
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in situ detoxification of the fermentation medium during γ decalactone production with the yeast sporidiobolus salmonicolor
Biotechnology Progress, 1999Co-Authors: Laurent Dufosse, Alain Latrasse, Gilles Feron, I. Souchon, H. E. SpinnlerAbstract:gamma-Decalactone (gamma-C10) is known to be highly toxic for the microorganims used for its production. In this work, three techniques were studied in order to overcome this toxicity during a bioconversion process using ricinoleic acid as precursor of the lactone: in situ trapping in oily phases, in porous hydrophobic sorbents and in beta-cyclodextrins. Oily phases added to the media (olive, Miglyol, tributyrin, and paraffin) had a protective effect on Sp. salmonicolor, and they improved the lactone production. beta-cyclodextrins, which have a hydrophobic cavity that can trap molecules such as gamma-C10, have been used to protect the yeasts. The results showed insufficient preservation of cell viability. Some sorbents (activated carbon and polystyrene-based sorbents) were successfully tested during bioconversion. In all cases viability exceeded the reference one. Nevertheless the aroma production was 30% lower than the reference. All of these solutions led to some enhancement of the cell viability during bioconversion of methyl ricinoleate to gamma-C10. For improvement of the lactone production, the oil trapping method seemed to be the best with the experimental conditions tested.
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Production, Identification, and Toxicity of (gamma)-Decalactone and 4-Hydroxydecanoic Acid from Sporidiobolus spp.
Applied and environmental microbiology, 1996Co-Authors: Gilles Feron, Laurent Dufosse, Pascal Bonnarme, E Pierard, J L Quere, H. E. SpinnlerAbstract:During the bioconversion of ricinoleic acid to (gamma)-decalactone under controlled pH conditions, Sporidiobolus salmonicolor produced only the lactone form, while Sporidiobolus ruinenii produced both the lactone form and a precursor. By using gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared analysis techniques, the precursor was identified as 4-hydroxydecanoic acid. The levels of production in the presence of high concentrations of ricinoleic acid methyl ester differed in the two Sporidiobolus species. This difference was due on the one hand to the high sensitivity of S. salmonicolor to the lactone and on the other hand to the high level of 4-hydroxydecanoic acid produced by S. ruinenii. 4-Hydroxydecanoic acid is much less toxic to the microorganisms than the lactone. In contrast to S. ruinenii, S. salmonicolor is not able to catabolize 4-hydroxydecanoic acid.
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Chirality of the γ‐lactones formed by Fusarium poae INRA 45
Chirality, 1993Co-Authors: Alain Latrasse, Elisabeth Guichard, Catherine Piffaut, Nicole Fournier, Laurent DufosseAbstract:A filamentous fungus, Fusarium poae INRA 45, was grown in two liquid Czapek-type media (a Czapek medium, and a yeast extract plus casaminoacids-enriched Czapek medium). Eight Gamma-Lactones, i.e., gamma-penta-, gamma-octa-, gamma-nona-, gamma-deca-, and gamma-dodecalactone, (6Z)-gamma- and (6E)-gamma-dodecenolactones, and a di-unsaturated gamma-dodecalactone, were tentatively, or conclusively, identified by capillary gas chromatography (GC) and coupled GC-MS, in the volatile fractions of the cultures. Kinetics of the formation of gamma-dodecalactone, (6Z)-gamma- and (6E)-gamma-dodecenolactones, (three major lactones), and gamma-dodecalactone (a minor lactone) were quantitatively studied by computerized GC integration. Variations of the (R/S) ratios of the lactone enantiomers were quantitatively studied by computerized multidimensional gas chromatography (MDGC) integration. The levels of the lactones were superior in the enriched Czapek-type medium to those of the Czapek medium, but the compositions of these media did not influence significantly the (R/S) ratios of these lactones. Formation of the enantiomers is discussed in terms of metabolism of potential precursors.
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chirality of the γ lactones formed by fusarium poae inra 45
Chirality, 1993Co-Authors: Alain Latrasse, Elisabeth Guichard, Catherine Piffaut, Nicole Fournier, Laurent DufosseAbstract:A filamentous fungus, Fusarium poae INRA 45, was grown in two liquid Czapek-type media (a Czapek medium, and a yeast extract plus casaminoacids-enriched Czapek medium). Eight Gamma-Lactones, i.e., gamma-penta-, gamma-octa-, gamma-nona-, gamma-deca-, and gamma-dodecalactone, (6Z)-gamma- and (6E)-gamma-dodecenolactones, and a di-unsaturated gamma-dodecalactone, were tentatively, or conclusively, identified by capillary gas chromatography (GC) and coupled GC-MS, in the volatile fractions of the cultures. Kinetics of the formation of gamma-dodecalactone, (6Z)-gamma- and (6E)-gamma-dodecenolactones, (three major lactones), and gamma-dodecalactone (a minor lactone) were quantitatively studied by computerized GC integration. Variations of the (R/S) ratios of the lactone enantiomers were quantitatively studied by computerized multidimensional gas chromatography (MDGC) integration. The levels of the lactones were superior in the enriched Czapek-type medium to those of the Czapek medium, but the compositions of these media did not influence significantly the (R/S) ratios of these lactones. Formation of the enantiomers is discussed in terms of metabolism of potential precursors.
Shoji Nakamori - One of the best experts on this subject based on the ideXlab platform.
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Total synthesis of the antitumor acetogenin mosin B: desymmetrization approach to the stereodivergent synthesis of threo/trans/erythro-type acetogenins.
Chemistry - A European Journal, 2003Co-Authors: Naoyoshi Maezaki, Naoto Kojima, Atsunobu Sakamoto, Chuzo Iwata, Tetsuaki Tanaka, Hiroaki Tominaga, Morito Monden, Bazarragchaa Damdinsuren, Shoji NakamoriAbstract:A total synthesis of the threo/trans/erythro-type acetogenin mosin B and one of its diastereomers has been achieved. The carbon skeleton is assembled in a convergent fashion from two segments (a THF ring segment and a Gamma-Lactone segment) through the Nozaki-Hiyama-Kishi reaction. The THF ring segment was stereoselectively constructed by a stereodivergent synthesis starting from a common intermediate (4-cyclohexene-1,2-diol) based on a desymmetrization strategy. The Gamma-Lactone segment was synthesized by coupling a triflate and a chiral alpha-sulfenyl Gamma-Lactone. By virtue of these synthetic results, we suggest that the absolute configuration of natural mosin B is 1 a. Antiproliferative effects of 1 a and 1 b were also investigated.
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total synthesis of the antitumor acetogenin mosin b desymmetrization approach to the stereodivergent synthesis of threo trans erythro type acetogenins
Chemistry: A European Journal, 2003Co-Authors: Naoyoshi Maezaki, Naoto Kojima, Atsunobu Sakamoto, Chuzo Iwata, Tetsuaki Tanaka, Hiroaki Tominaga, Morito Monden, Bazarragchaa Damdinsuren, Shoji NakamoriAbstract:A total synthesis of the threo/trans/erythro-type acetogenin mosin B and one of its diastereomers has been achieved. The carbon skeleton is assembled in a convergent fashion from two segments (a THF ring segment and a Gamma-Lactone segment) through the Nozaki-Hiyama-Kishi reaction. The THF ring segment was stereoselectively constructed by a stereodivergent synthesis starting from a common intermediate (4-cyclohexene-1,2-diol) based on a desymmetrization strategy. The Gamma-Lactone segment was synthesized by coupling a triflate and a chiral alpha-sulfenyl Gamma-Lactone. By virtue of these synthetic results, we suggest that the absolute configuration of natural mosin B is 1 a. Antiproliferative effects of 1 a and 1 b were also investigated.
Jean-pierre Lepoittevin - One of the best experts on this subject based on the ideXlab platform.
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chronic actinic dermatitis to sesquiterpene lactones 2 2 photoreaction toward thymidine of and α methylene hexahydrobenzofuranone with a cis ring junction
Photochemistry and Photobiology, 2010Co-Authors: Sébastien Fuchs, Valérie Berl, Jean-pierre LepoittevinAbstract:(+) and (-) alpha-methylene-hexahydrobenzofuranone derivatives with a stereochemically pure cis ring junction were used as models of sesquiterpene lactones to study their photoreactivity toward thymidine. After 313 nm irradiation of a deoxygenated acetone solution of lactone models and thymidine, six [2+2] photoadducts were isolated for each enantiomer and fully characterized by a combination of NMR experiments. A common syn regioselectivity and exo stereoselectivity were observed for photoadducts. This high photoreactivity of alpha-methylene-gamma-butyrolactone ring toward thymidine could be an explanation of the progressive evolution of allergic contact dermatitis toward chronic actinic dermatitis.
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Chronic Actinic Dermatitis to Sesquiterpene Lactones: [2+2] Photoreaction Toward Thymidine of (+) and (−) α‐Methylene‐Hexahydrobenzofuranone with a cis Ring Junction
Photochemistry and Photobiology, 2010Co-Authors: Sébastien Fuchs, Valérie Berl, Jean-pierre LepoittevinAbstract:(+) and (-) alpha-methylene-hexahydrobenzofuranone derivatives with a stereochemically pure cis ring junction were used as models of sesquiterpene lactones to study their photoreactivity toward thymidine. After 313 nm irradiation of a deoxygenated acetone solution of lactone models and thymidine, six [2+2] photoadducts were isolated for each enantiomer and fully characterized by a combination of NMR experiments. A common syn regioselectivity and exo stereoselectivity were observed for photoadducts. This high photoreactivity of alpha-methylene-gamma-butyrolactone ring toward thymidine could be an explanation of the progressive evolution of allergic contact dermatitis toward chronic actinic dermatitis.
J. M. Belin - One of the best experts on this subject based on the ideXlab platform.
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Catabolism of hydroxyacids and biotechnological production of lactones by Yarrowia lipolytica.
Applied Microbiology and Biotechnology, 2003Co-Authors: Yves Waché, J. M. Nicaud, M. Aguedo, J. M. BelinAbstract:The gamma- and delta-lactones of less than 12 carbons constitute a group of compounds of great interest to the flavour industry. It is possible to produce some of these lactones through biotechnology. For instance, gamma-decalactone can be obtained by biotransformation of methyl ricinoleate. Among the organisms used for this bioproduction, Yarrowia lipolytica is a yeast of choice. It is well adapted to growth on hydrophobic substrates, thanks to its efficient and numerous lipases, cytochrome P450, acyl-CoA oxidases and its ability to produce biosurfactants. Furthermore, genetic tools have been developed for its study. This review deals with the production of lactones by Y. lipolytica with special emphasis on the biotransformation of methyl ricinoleate to gamma-decalactone. When appropriate, information from the lipid metabolism of other yeast species is presented.
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Mechanisms underlying the toxicity of lactone aroma compounds towards the producing yeast cells.
Journal of Applied Microbiology, 2003Co-Authors: M. Aguedo, Yves Waché, Laurent Beney, J. M. BelinAbstract:AIMS: To study the fundamental mechanisms of toxicity of the fruity aroma compound gamma-decalactone, that lead to alterations in cell viability during its biotechnological production by yeast cells; Yarrowia lipolytica that is able to produce high amounts of this metabolite was used here as a model. METHODS AND RESULTS: Lactone concentrations above 150 mg l-1 inhibited cell growth, depolarized the living cells and increased membrane fluidity. Infrared spectroscopic measurements revealed that the introduction of the lactone into model phospholipid bilayers, decreased the phase transition temperature. Moreover, the H+-ATPase activity in membrane preparations was strongly affected by the presence of the lactone. On the other hand, only a slight decrease in the intracellular pH occurred. CONCLUSIONS: We propose that the toxic effects of gamma-decalactone on yeast may be initially linked to a strong interaction of the compound with cell membrane lipids and components. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings may enable the elaboration of strategies to improve yeast cell viability during the process of lactones bioproduction.
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Role of beta-oxidation enzymes in gamma-decalactone production by the yeast Yarrowia lipolytica.
Applied and Environmental Microbiology, 2001Co-Authors: Yves Waché, J. M. Nicaud, M. Aguedo, A. Choquet, I. L. Gatfield, J. M. BelinAbstract:Some microorganisms can transform methyl ricinoleate into gamma-decalactone, a valuable aroma compound, but yields of the bioconversion are low due to (i) incomplete conversion of ricinoleate (C(18)) to the C(10) precursor of gamma-decalactone, (ii) accumulation of other lactones (3-hydroxy-gamma-decalactone and 2- and 3-decen-4-olide), and (iii) gamma-decalactone reconsumption. We evaluated acyl coenzyme A (acyl-CoA) oxidase activity (encoded by the POX1 through POX5 genes) in Yarrowia lipolytica in lactone accumulation and gamma-decalactone reconsumption in POX mutants. Mutants with no acyl-CoA oxidase activity could not reconsume gamma-decalactone, and mutants with a disruption of pox3, which encodes the short-chain acyl-CoA oxidase, reconsumed it more slowly. 3-Hydroxy-gamma-decalactone accumulation during transformation of methyl ricinoleate suggests that, in wild-type strains, beta-oxidation is controlled by 3-hydroxyacyl-CoA dehydrogenase. In mutants with low acyl-CoA oxidase activity, however, the acyl-CoA oxidase controls the beta-oxidation flux. We also identified mutant strains that produced 26 times more gamma-decalactone than the wild-type parents.
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Involvement of acyl coenzyme A oxidase isozymes in biotransformation of methyl ricinoleate into gamma-decalactone by Yarrowia lipolytica.
Applied and Environmental Microbiology, 2000Co-Authors: Yves Waché, J. M. Nicaud, M. Aguedo, C. Laroche, K. Bergmark, C. Møller-andersen, M. T. Le Dall, H. Wang, J. M. BelinAbstract:We reported previously on the function of acyl coenzyme A (acyl-CoA) oxidase isozymes in the yeast Yarrowia lipolytica by investigating strains disrupted in one or several acyl-CoA oxidase-encoding genes (POX1 through POX5) (H. Wang et al., J. Bacteriol. 181:5140-5148, 1999). Here, these mutants were studied for lactone production. Monodisrupted strains produced similar levels of lactone as the wild-type strain (50 mg/liter) except for Deltapox3, which produced 220 mg of gamma-decalactone per liter after 24 h. The Deltapox2 Deltapox3 double-disrupted strain, although slightly affected in growth, produced about 150 mg of lactone per liter, indicating that Aox2p was not essential for the biotransformation. The Deltapox2 Deltapox3 Deltapox5 triple-disrupted strain produced and consumed lactone very slowly. On the contrary, the Deltapox2 Deltapox3 Deltapox4 Deltapox5 multidisrupted strain did not grow or biotransform methyl ricinoleate into gamma-decalactone, demonstrating that Aox4p is essential for the biotransformation.
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Peroxisomal beta-oxidation activities and gamma-decalactone production by the yeast Yarrowia lipolytica.
Applied Microbiology and Biotechnology, 1998Co-Authors: Y. Pagot, Yves Waché, J. M. Nicaud, A. Le Clainche, J. M. BelinAbstract:gamma-Decalactone is a peachy aroma compound resulting from the peroxisomal beta-oxidation of ricinoleic acid by yeasts. The expression levels of acyl-CoA oxidase (gene deletion) and 3-ketoacyl-CoA thiolase activities (gene amplification on replicative plasmids) were modified in the yeast Yarrowia lipolytica. The effects of these modifications on beta-oxidation were measured. Overexpression of thiolase activity did not have any effect on the overall beta-oxidation activity. The disruption of one of the acyl-CoA oxidase genes resulted in an enhanced activity. The enhancement led to an increase of overall beta-oxidation activity but reduced the gamma-decalactone production rates. This seemed to indicate a non-rate-limiting role for beta-oxidation in the biotransformation of ricinoleic acid to gamma-decalactone by the yeast Yarrowia lipolytica. All strains produced and then consumed gamma-decalactone. We checked the ability of the different strains to consume gamma-decalactone in a medium containing the lactone as sole carbon source. The consumption of the strain overexpressing acyl-CoA oxidase activity was higher than that of the wild-type strain. We concluded that peroxisomal beta-oxidation is certainly involved in gamma-decalactone catabolism by the yeast Y. lipolytica. The observed production rates probably depend on an equilibrium between production and consumption of the lactone.
Alain Latrasse - One of the best experts on this subject based on the ideXlab platform.
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In Situ Detoxification of the Fermentation Medium during γ‐Decalactone Production with the Yeast Sporidiobolus salmonicolor
Biotechnology progress, 1999Co-Authors: Laurent Dufosse, Alain Latrasse, Gilles Feron, I. Souchon, H. E. SpinnlerAbstract:gamma-Decalactone (gamma-C10) is known to be highly toxic for the microorganims used for its production. In this work, three techniques were studied in order to overcome this toxicity during a bioconversion process using ricinoleic acid as precursor of the lactone: in situ trapping in oily phases, in porous hydrophobic sorbents and in beta-cyclodextrins. Oily phases added to the media (olive, Miglyol, tributyrin, and paraffin) had a protective effect on Sp. salmonicolor, and they improved the lactone production. beta-cyclodextrins, which have a hydrophobic cavity that can trap molecules such as gamma-C10, have been used to protect the yeasts. The results showed insufficient preservation of cell viability. Some sorbents (activated carbon and polystyrene-based sorbents) were successfully tested during bioconversion. In all cases viability exceeded the reference one. Nevertheless the aroma production was 30% lower than the reference. All of these solutions led to some enhancement of the cell viability during bioconversion of methyl ricinoleate to gamma-C10. For improvement of the lactone production, the oil trapping method seemed to be the best with the experimental conditions tested.
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in situ detoxification of the fermentation medium during γ decalactone production with the yeast sporidiobolus salmonicolor
Biotechnology Progress, 1999Co-Authors: Laurent Dufosse, Alain Latrasse, Gilles Feron, I. Souchon, H. E. SpinnlerAbstract:gamma-Decalactone (gamma-C10) is known to be highly toxic for the microorganims used for its production. In this work, three techniques were studied in order to overcome this toxicity during a bioconversion process using ricinoleic acid as precursor of the lactone: in situ trapping in oily phases, in porous hydrophobic sorbents and in beta-cyclodextrins. Oily phases added to the media (olive, Miglyol, tributyrin, and paraffin) had a protective effect on Sp. salmonicolor, and they improved the lactone production. beta-cyclodextrins, which have a hydrophobic cavity that can trap molecules such as gamma-C10, have been used to protect the yeasts. The results showed insufficient preservation of cell viability. Some sorbents (activated carbon and polystyrene-based sorbents) were successfully tested during bioconversion. In all cases viability exceeded the reference one. Nevertheless the aroma production was 30% lower than the reference. All of these solutions led to some enhancement of the cell viability during bioconversion of methyl ricinoleate to gamma-C10. For improvement of the lactone production, the oil trapping method seemed to be the best with the experimental conditions tested.
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chirality of the γ lactones formed by fusarium poae inra 45
Chirality, 1993Co-Authors: Alain Latrasse, Elisabeth Guichard, Catherine Piffaut, Nicole Fournier, Laurent DufosseAbstract:A filamentous fungus, Fusarium poae INRA 45, was grown in two liquid Czapek-type media (a Czapek medium, and a yeast extract plus casaminoacids-enriched Czapek medium). Eight Gamma-Lactones, i.e., gamma-penta-, gamma-octa-, gamma-nona-, gamma-deca-, and gamma-dodecalactone, (6Z)-gamma- and (6E)-gamma-dodecenolactones, and a di-unsaturated gamma-dodecalactone, were tentatively, or conclusively, identified by capillary gas chromatography (GC) and coupled GC-MS, in the volatile fractions of the cultures. Kinetics of the formation of gamma-dodecalactone, (6Z)-gamma- and (6E)-gamma-dodecenolactones, (three major lactones), and gamma-dodecalactone (a minor lactone) were quantitatively studied by computerized GC integration. Variations of the (R/S) ratios of the lactone enantiomers were quantitatively studied by computerized multidimensional gas chromatography (MDGC) integration. The levels of the lactones were superior in the enriched Czapek-type medium to those of the Czapek medium, but the compositions of these media did not influence significantly the (R/S) ratios of these lactones. Formation of the enantiomers is discussed in terms of metabolism of potential precursors.
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Chirality of the γ‐lactones formed by Fusarium poae INRA 45
Chirality, 1993Co-Authors: Alain Latrasse, Elisabeth Guichard, Catherine Piffaut, Nicole Fournier, Laurent DufosseAbstract:A filamentous fungus, Fusarium poae INRA 45, was grown in two liquid Czapek-type media (a Czapek medium, and a yeast extract plus casaminoacids-enriched Czapek medium). Eight Gamma-Lactones, i.e., gamma-penta-, gamma-octa-, gamma-nona-, gamma-deca-, and gamma-dodecalactone, (6Z)-gamma- and (6E)-gamma-dodecenolactones, and a di-unsaturated gamma-dodecalactone, were tentatively, or conclusively, identified by capillary gas chromatography (GC) and coupled GC-MS, in the volatile fractions of the cultures. Kinetics of the formation of gamma-dodecalactone, (6Z)-gamma- and (6E)-gamma-dodecenolactones, (three major lactones), and gamma-dodecalactone (a minor lactone) were quantitatively studied by computerized GC integration. Variations of the (R/S) ratios of the lactone enantiomers were quantitatively studied by computerized multidimensional gas chromatography (MDGC) integration. The levels of the lactones were superior in the enriched Czapek-type medium to those of the Czapek medium, but the compositions of these media did not influence significantly the (R/S) ratios of these lactones. Formation of the enantiomers is discussed in terms of metabolism of potential precursors.
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Chiral Gamma-Lactones from Fusarium poae: enentiomeric ratios and sensory differentiation of cis-6-gamma-dodecenolactone enantiomers
Zeitschrift für Lebensmitteluntersuchung und -Forschung A, 1991Co-Authors: Elisabeth Guichard, Alain Latrasse, Armin Mosandl, Angelika Hollnagel, Robert HenryAbstract:Chiral Gamma-Lactones from Fusarium poae: enentiomeric ratios and sensory differentiation of cis-6-gamma-dodecenolactone enantiomers
