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Thomas A. Mckeon - One of the best experts on this subject based on the ideXlab platform.
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ricinus communis contains an acyl coa synthetase that preferentially activates Ricinoleate to its coa thioester
Lipids, 2007Co-Authors: Grace Q. Chen, Sung T Kang, Thomas A. MckeonAbstract:As part of our effort to identify enzymes that are critical for producing large amounts of Ricinoleate in castor oil, we have isolated three cDNAs encoding acyl-CoA synthetase (ACS) in the castor plant. Analysis of the cDNA sequences reveals that two of them, designated RcACS 2 and RcACS 4, contain complete coding regions corresponding to 694 and 690 amino acids, respectively. The third cDNA, RcACS 1, encodes a truncated gene sequence. The RcACS 2 and RcACS 4 share 77% identity at the amino acid sequence level. Complementation tests showed that both RcACS 2 and RcACS 4 successfully restored growth of a yeast mutant strain (YB525) deficient in ACS. Lysates from yeast cells expressing RcACS 2 and 4 were enzymatically active when using 14C-labeled oleic acid as a substrate. A cell fractionation study indicates that RcACS 2 and 4 are mainly associated with membranes. Substrate specificity assays indicate that the RcACS 2 preferentially activates Ricinoleate, while the RcACS 4 has a preference for nonhydroxy fatty acids.
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The Enzymology of Castor Oil Biosynthesis
2007Co-Authors: Thomas A. Mckeon, Grace Q. Chen, Xiaohua He, Yeh-jin Ahn, J.-t. LinAbstract:The castor plant Ricinus communis L., Euphorbiaceae produces seeds containing a unique oil. Castor oil is the only commodity vegetable oil that contains significant amounts of hydroxy fatty acid. This fatty acid is ricinoleic acid (12-hydroxy oleic acid) (Fig. 1) and it comprises up to 90% of the total fatty acid (FA) content of castor oil. Due to the physical and chemical properties imparted by the mid-chain hydroxy group, the oil has many important industrial uses. However, due to the presence of the toxic protein ricin and hyperallergenic 2S albumins, the production of castor oil is problematic. One logical approach to solving the biohazard problem presented by castor meal is to produce Ricinoleate in plants lacking these noxious components. Several researchers have attempted to produce a Ricinoleate oil by transgenic expression of the oleoyl-12-hydroxylase, the enzyme that is responsible for Ricinoleate biosynthesis. This approach of introducing a single gene to engineer a novel oil composition was pioneered by the Calgene company the in order to develop laurate canola (Voelker et al. 1992). Expression of the cDNA that encodes the oleoyl-12-hydroxylase (or FAH, for fatty acyl hydroxylase), resulted in the accumulation of a low level of hydroxy fatty acids in tobacco and Arabidopsis (Broun and Somerville 1997). These results suggested that the FAH gene by itself is not sufficient to produce high levels of Ricinoleate in plants other than castor (McKeon and Lin 2002). An in vitro system using microsomes isolated from developing castor seed endosperm provided an effective means for following fatty acid hydroxylation and castor oil biosynthesis (McKeon et al. 1997; Lin et al. 1998a). Using metabolic profiling tools for analyzing lipid biosynthetic products (Lin et al. 1998a, 2002), the analysis of radiolabeled products from fatty acids incubated in the microsomal system enabled identification of several enzyme activities that give castor its unique ability to produce a high Ricinoleate oil (McKeon and Lin 2002). Based on these studies, the preferential incorporation of Ricinoleate into triacylglycerol (TG) led us to identify the final step in oil biosynthesis (Fig. 2) as a key step in maintaining high Ricinoleate content while minimizing oleate incorporation into the TG fraction. Table 1 shows that the microsomes incorporate Ricinoleate preferentially by a factor of 6-fold. The diacylglycerol acyltransferase (DGAT) is a transmembrane enzyme that catalyzes the acylation of diacylglycerol (DG) to TG, using acylCoA as the source for the final acyl group. This step has long been considered to be a rate limiting step in oil biosynthesis, and considerable evidence has accumulated to indicate that altered DGAT activity levels dramatically affect the yield of oil (He et al. 2004). AcylCoA synthetases (ACS) produce the acyl-donor
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Incorporation of laurate and hydroxylaurate into phosphatidylcholines and acylglycerols in castor microsomes
Journal of the American Oil Chemists' Society, 2005Co-Authors: J.-t. Lin, Seiji Wani, Tasha Nguyen, Thomas A. MckeonAbstract:Because castor produces oil with a high content of hydroxyl FA (90% Ricinoleate), we were interested in determining the flexibility of castor seed microsomes in incorporating other hydroxyl FA into castor oil. To this end, we incubated the [^14C]-labeled 12:0 FA laurate (La), 11-hydroxylaurate, and 12-hydroxylaurate with castor microsomes that were capable of synthesizing castor oil. The molecular species of PC and acylglycerols (AG) incorporating these nonendogenous FA of castor were identified by reversed-phase C_8 and C_18 HPLC, respectively. [^14C]Laurate was incorporated into the molecular species of PC and AG at levels of 10 and 4%, respectively, that of [^14C]Ricinoleate. Similar to those from the incorporation of six [^14C]FA reported previously [Ricinoleate (R), oleate (O), linoleate (L), linolenate (Ln), stearate (S), and palmitate (P)], the molecular species of PC incorporating [^14C]laureate were LLa-PC>PLa-PC>OLa-PC>LnLa-PC>SLa-PC>RLa-PC. The molecular species of AG incorporating [^14C]laurate were RRLa>LaLa>RLa>RLLa>ROLa>LOLa>LLLa>LLa>LLnLa>RSLa>OOLa. The retention times for lipids incorporating laurate were similar to those of lipids incorporating linolenate, because the equivalent carbon numbers of laurate and linolenate are the same. Relative retention times of the molecular species of PC and AG containing laurate are also reported here. The incorporation of 11-hydroxylaurate and 12-hydroxylaurate into PC and AG was not detected.
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comparison of the incorporation of oleate and Ricinoleate into phosphatidylcholines and acylglycerols in soybean microsomes
Journal of Agricultural and Food Chemistry, 2004Co-Authors: J.-t. Lin, Marc D Ikeda, Thomas A. MckeonAbstract:The incorporations of oleate (endogenous) and Ricinoleate (nonendogenous) into phosphatidylcholine (PC) and acylglycerol (AG) in immature soybean microsomes were compared. [ 14 C]Oleate and [ 14 C]-Ricinoleate were incubated individually with soybean microsomal preparations for up to 4 h, and molecular species of PC and AG incorporated were identified and quantified by HPLC. The activities of acyl CoA:lysoPC acyltransferase and phospholipase A 2 are in general not affected by the fatty acid (FA) chain at the sn-1 position. However, comparison between oleate and Ricinoleate revealed that different FA incorporated at sn-2 of PC showed some different selection of the molecular species of lysoPC. The incorporation of [ 14 C]Ricinoleate into triacylglycerols (TAG) was slightly better than that of [ 14 C]oleate and indicated that soybean was capable of incorporating Ricinoleate into TAG when Ricinoleate can be produced endogenously in a transgenic soybean. The incorporation of FA into TAG in soybean microsomes was much slower than that in castor microsomes.
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simultaneous separation of monoacylglycerols free fatty acids and fatty acid methyl and ethyl esters by reversed phase hplc
Journal of Liquid Chromatography & Related Technologies, 2004Co-Authors: Charlotta Turner, Thomas A. MckeonAbstract:Abstract We have developed a reversed‐phase C18 high performance liquid chromatography (HPLC) method to separate molecular species of monoacylglycerols (MAG), fatty acids, fatty acid methyl esters, and fatty acid ethyl esters, simultaneously. This system also separates the regioisomers, 2‐acyl‐sn‐glycerol and 1‐acyl‐sn‐glycerol, with 2‐acyl‐sn‐glycerol eluting earlier than 1‐acyl‐sn‐glycerol. The elution order of the fatty acid and esters was Ricinoleate, linolenate, linoleate, palmitate, oleate, and stearate. This method is also useful for the identification of radiolabeled metabolites using co‐chromatography.
Jeanmarc Belin - One of the best experts on this subject based on the ideXlab platform.
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impact of surfactants on the biotransformation of methyl Ricinoleate into γ decalactone by yarrowia lipolytica
Journal of Molecular Catalysis B-enzymatic, 2004Co-Authors: M. Aguedo, Yves Waché, Florence Coste, Florence Husson, Jeanmarc BelinAbstract:Surfactants play a key role in the biotechnological degradation of hydrophobic substrates, however this role is often misunderstood. During the biotransformation of methyl Ricinoleate into the aroma compound γ-decalactone by the yeast Yarrowia lipolytica, a direct contact occurs between the surface of the cells and the small droplets of substrate. The impact of a series of surfactants on this process was investigated. Both ionic surfactants tested were toxic towards the yeast. This effect may be linked to a decrease in the cell membrane integrity. The interfacial area of the emulsion varied according to the non-ionic surfactant used, and this factor was correlated with the productivity of the biotransformation. By evaluating the effect of surfactants on the capacity of the cells to adhere to decane (MATH test), it was shown that the adhesion of methyl Ricinoleate on yeast surface is not a rate-limiting point for the process.
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Increased electron donor and electron acceptor characters enhance the adhesion between oil droplets and cells of Yarrowia lipolytica as evaluated by a new cytometric assay.
Journal of Agricultural and Food Chemistry, 2003Co-Authors: M. Aguedo, Yves Waché, Virginie Mazoyer, Anabelle Sequeira-le Grand, Jeanmarc BelinAbstract:The adhesion of methyl Ricinoleate droplets to cells of the yeast Yarrowia lipolytica was investigated. A new cytometric method, relying on the double staining of fatty globules with Nile Red and of cells with Calcofluor, enabled us to quantify methyl Ricinoleate droplet adhesion to cells precultured on a hydrophilic or on a hydrophobic carbon source. In this last case, droplet adsorption was enhanced and a MATS (microbial adhesion to solvents) test revealed that this increase was due to Lewis acid-base interactions and not to an increase in the hydrophobic properties of the cell surface. These preliminary results demonstrate that the developed cytometric method is promising for various applications concerning the study of interactions between microorganisms and an emulsified hydrophobic substrates.
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medium size droplets of methyl Ricinoleate are reduced by cell surface activity in the γ decalactone production by yarrowia lipolytica
Letters in Applied Microbiology, 2000Co-Authors: Yves Waché, J. M. Nicaud, M. Aguedo, K. Bergmark, J. L. Courthaudon, Jeanmarc BelinAbstract:. Size of methyl Ricinoleate droplets during biotransformation into γ-decalactone by Yarrowia lipolytica was measured in both homogenized and non-homogenized media. In non-homogenized but shaken medium, droplets had an average volume surface diameter d32 of 2·5 µm whereas it was 0·7 µm in homogenized and shaken medium. But as soon as yeast cells were inoculated, both diameters became similar at about 0·7 µm and did not vary significantly until the end of the culture. The growth of Y. lipolytica in both media was very similar except for the lag phase which was lowered in homogenized medium conditions.
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presumptive involvement of methyl Ricinoleate β oxidation in the production of γ decalactone by the yeast pichia guilliermondii
Fems Microbiology Letters, 1993Co-Authors: Anne Endrizzi, Abalo Charles Awade, Jeanmarc BelinAbstract:Production of γ-decalactone by yeasts from fatty acids has been reported but little is known about the mechanisms involved in this process. This paper provides information about the mechanisms involved in the production of γ-decalactone by Pichia guilliermondii in the presence of a fatty acid methyl ester. Culturing of P. guilliermondii in media containing methyl Ricinoleate (12(R)-hydroxy-9(Z)-octadecenoic acid) revealed a coordinated induction of β-oxidation activities and γ-decalactone production. However, no γ-decalactone synthesis was noted when methyl Ricinoleate was changed into methyloleate or methyl linoleate, even though these fatty acid methyl esters are able to induce β-oxidation activities in P. guilliermondii. These observations led us to conclude that methyl Ricinoleate is an inducer of β-oxidation and is probably the substrate for γ-decalactone production. The fatty acid ester β-oxidation should be involved, at least in part, in this production.
M. Aguedo - One of the best experts on this subject based on the ideXlab platform.
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impact of surfactants on the biotransformation of methyl Ricinoleate into γ decalactone by yarrowia lipolytica
Journal of Molecular Catalysis B-enzymatic, 2004Co-Authors: M. Aguedo, Yves Waché, Florence Coste, Florence Husson, Jeanmarc BelinAbstract:Surfactants play a key role in the biotechnological degradation of hydrophobic substrates, however this role is often misunderstood. During the biotransformation of methyl Ricinoleate into the aroma compound γ-decalactone by the yeast Yarrowia lipolytica, a direct contact occurs between the surface of the cells and the small droplets of substrate. The impact of a series of surfactants on this process was investigated. Both ionic surfactants tested were toxic towards the yeast. This effect may be linked to a decrease in the cell membrane integrity. The interfacial area of the emulsion varied according to the non-ionic surfactant used, and this factor was correlated with the productivity of the biotransformation. By evaluating the effect of surfactants on the capacity of the cells to adhere to decane (MATH test), it was shown that the adhesion of methyl Ricinoleate on yeast surface is not a rate-limiting point for the process.
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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 γ- and δ-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, γ-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 γ-decalactone. When appropriate, information from the lipid metabolism of other yeast species is presented.
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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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Increased electron donor and electron acceptor characters enhance the adhesion between oil droplets and cells of Yarrowia lipolytica as evaluated by a new cytometric assay.
Journal of Agricultural and Food Chemistry, 2003Co-Authors: M. Aguedo, Yves Waché, Virginie Mazoyer, Anabelle Sequeira-le Grand, Jeanmarc BelinAbstract:The adhesion of methyl Ricinoleate droplets to cells of the yeast Yarrowia lipolytica was investigated. A new cytometric method, relying on the double staining of fatty globules with Nile Red and of cells with Calcofluor, enabled us to quantify methyl Ricinoleate droplet adhesion to cells precultured on a hydrophilic or on a hydrophobic carbon source. In this last case, droplet adsorption was enhanced and a MATS (microbial adhesion to solvents) test revealed that this increase was due to Lewis acid-base interactions and not to an increase in the hydrophobic properties of the cell surface. These preliminary results demonstrate that the developed cytometric method is promising for various applications concerning the study of interactions between microorganisms and an emulsified hydrophobic substrates.
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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.
Yves Waché - One of the best experts on this subject based on the ideXlab platform.
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impact of surfactants on the biotransformation of methyl Ricinoleate into γ decalactone by yarrowia lipolytica
Journal of Molecular Catalysis B-enzymatic, 2004Co-Authors: M. Aguedo, Yves Waché, Florence Coste, Florence Husson, Jeanmarc BelinAbstract:Surfactants play a key role in the biotechnological degradation of hydrophobic substrates, however this role is often misunderstood. During the biotransformation of methyl Ricinoleate into the aroma compound γ-decalactone by the yeast Yarrowia lipolytica, a direct contact occurs between the surface of the cells and the small droplets of substrate. The impact of a series of surfactants on this process was investigated. Both ionic surfactants tested were toxic towards the yeast. This effect may be linked to a decrease in the cell membrane integrity. The interfacial area of the emulsion varied according to the non-ionic surfactant used, and this factor was correlated with the productivity of the biotransformation. By evaluating the effect of surfactants on the capacity of the cells to adhere to decane (MATH test), it was shown that the adhesion of methyl Ricinoleate on yeast surface is not a rate-limiting point for the process.
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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 γ- and δ-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, γ-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 γ-decalactone. When appropriate, information from the lipid metabolism of other yeast species is presented.
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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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Increased electron donor and electron acceptor characters enhance the adhesion between oil droplets and cells of Yarrowia lipolytica as evaluated by a new cytometric assay.
Journal of Agricultural and Food Chemistry, 2003Co-Authors: M. Aguedo, Yves Waché, Virginie Mazoyer, Anabelle Sequeira-le Grand, Jeanmarc BelinAbstract:The adhesion of methyl Ricinoleate droplets to cells of the yeast Yarrowia lipolytica was investigated. A new cytometric method, relying on the double staining of fatty globules with Nile Red and of cells with Calcofluor, enabled us to quantify methyl Ricinoleate droplet adhesion to cells precultured on a hydrophilic or on a hydrophobic carbon source. In this last case, droplet adsorption was enhanced and a MATS (microbial adhesion to solvents) test revealed that this increase was due to Lewis acid-base interactions and not to an increase in the hydrophobic properties of the cell surface. These preliminary results demonstrate that the developed cytometric method is promising for various applications concerning the study of interactions between microorganisms and an emulsified hydrophobic substrates.
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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.
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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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 γ- and δ-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, γ-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 γ-decalactone. When appropriate, information from the lipid metabolism of other yeast species is presented.
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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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Medium-size droplets of methyl Ricinoleate are reduced by cell-surface activity in the gamma-decalactone production by Yarrowia lipolytica.
Letters in Applied Microbiology, 2000Co-Authors: Yves Waché, J. M. Nicaud, M. Aguedo, K. Bergmark, J. L. Courthaudon, J. M. BelinAbstract:Size of methyl Ricinoleate droplets during biotransformation into gamma-decalactone by Yarrowia lipolytica was measured in both homogenized and non-homogenized media. In non-homogenized but shaken medium, droplets had an average volume surface diameter d32 of 2.5 microm whereas it was 0.7 microm in homogenized and shaken medium. But as soon as yeast cells were inoculated, both diameters became similar at about 0.7 microm and did not vary significantly until the end of the culture. The growth of Y. lipolytica in both media was very similar except for the lag phase which was lowered in homogenized medium conditions.
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Production of 6-pentyl-α-pyrone byTrichoderma harzianum from 18∶n fatty acid methyl esters
Biotechnology Letters, 1992Co-Authors: L. Serrano-carreon, Y. Hathout, M. Bensoussan, J. M. BelinAbstract:Biosynthesis of 6-pentyl-α-pyrone by Trichoderma harzianum in two different media was evaluated. Best yields were found in nitrogen deficient medium (C/N=60). Limited growth seems to favour the production of this lactone. When fungal cells, precultured in low nitrogen medium, were incubated on methyl Ricinoleate (10 g/l, C/N=60) an increase in 6-pentyl-α-pyrone production was observed in comparison with the media containing methyl oleate or methyl linoleate.
