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See detailPeroxisomal β-oxidation and Production of γ-decalactone by the Yeast Rhodotorula aurantiaca
Alchihab, Mohamed ULg; Dubois Dauphin, Robin ULg; Aguedo, Mario ULg et al

in Notulae Botanicae Horti Agrobotanici Cluj-Napoca (2010), 2

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See detailThe use of Macronet resins to recover decalactone produced by Rhodotorula aurantiaca from the culture broth
Alchihab, Mohamed ULg; Aldric, Jean-Marc ULg; Aguedo, Mario ULg et al

in Journal of Industrial Microbiology & Biotechnology (2010), 37(2), 167-172

During the biotransformation of castor oil into -decalactone, R. aurantiaca produced both the lactone form and its precursor (4-hydroxydecanoic acid). After six days of culture, a maximum yield of ... [more ▼]

During the biotransformation of castor oil into -decalactone, R. aurantiaca produced both the lactone form and its precursor (4-hydroxydecanoic acid). After six days of culture, a maximum yield of -decalactone of 6.5 g/l was obtained. The parameters of -decalactone adsorption on three Macronet resins (MN-202, MN-102 and MN-100) were investigated in water. Adsorption isotherms of -decalactone for the three Macronet resins were linear. The trapping of -decalactone produced by R. aurantiaca on these resins was then carried out. -Decalactone was eVectively retained by all the studied Macronet resins. The resin MN-202 trapped -decalactone more eYciently than MN-102 and MN-100. The percentages of -decalactone adsorbed on the resins MN-202, MN-102 and MN-100 were, respectively, 85, 75 and 81%, whereas around 70% of the adsorbed -decalactone was then desorbed. We propose an industrial process that uses Macronet resins to extract -decalactone from culture broth of R. aurantiaca. [less ▲]

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See detailRecovery of γ-decalactone produced by Rhodotorula aurantiaca from the culture broth using Macronet resins
Alchihab, Mohamed; Aldric, Jean-Marc ULg; Aguedo, Mario ULg et al

in New Biotechnology (2009, September), 25S

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See detailProduction of 3-hydroxy-γ-decalactone, the precursor of two decenolides with flavouring properties, by the yeast Yarrowia lipolytica
Escamilla Garcia, E.; Aguedo, Mario ULg; Gomes, N. et al

in Journal of Molecular Catalysis B : Enzymatic (2009), 57(1-4), 22-26

3-Hydroxy-γ-decalactone is the precursor of dec-2 and dec-3-en-4-olides which are valuable aroma compounds not yet produced. To promote the accumulation of this lactone, the yeast Yarrowia lipolytica was ... [more ▼]

3-Hydroxy-γ-decalactone is the precursor of dec-2 and dec-3-en-4-olides which are valuable aroma compounds not yet produced. To promote the accumulation of this lactone, the yeast Yarrowia lipolytica was placed in different environmental conditions aiming at altering β-oxidation fluxes. The concentration of substrate, pH, aeration and dissolved oxygen level were modified. We observed an important accumulation at low aeration (0.40 molar yields) and, to a lesser extent, at lower pH (0.15). As oxygen played a key-role, we evaluated its effect at fixed dissolved oxygen and at the pH which was the most favourable to the biotransformation (pH 4.5). At 5% and 30% dissolved oxygen, yields reached 0.50. β-Oxidation fluxes are very dependent on the presence of oxygen and conditions of accumulation of 3-hydroxy-γ-decalactone with very high yields were identified. These results are an important step in the production of the two decenolides. Moreover, they show the high dependence of β-oxidation fluxes on environmental conditions and relate these conditions to the accumulation of intermediates, results that are of interest to all the processes using yeast on lipids or alkanes. © 2008 Elsevier B.V. All rights reserved. [less ▲]

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See detailThe use of olive mill wastewater by wild type Yarrowia lipolytica strains: Medium supplementation and surfactant presence effect
Lopes, M.; Araújo, C.; Aguedo, Mario ULg et al

in Journal of Chemical Technology and Biotechnology (2009), 84(4), 533-537

Background: The aim of this work was to study the ability of two different wild type strains of the yeast Yarrowia lipolytica to grow on olive mill wastewater (OMW) and their potential to produce high ... [more ▼]

Background: The aim of this work was to study the ability of two different wild type strains of the yeast Yarrowia lipolytica to grow on olive mill wastewater (OMW) and their potential to produce high-value products such as lipases. Factors that affect cellular growth and OMW degradation were studied, such as nitrogen supplementation, cells concentration and surfactant addition. Results: Both strains, W29 and IMUFRJ 50682, were able to grow in OMW with 19 g L-1 of COD and approximately 800 mg L-1 of total phenols concentration. The strain W29 presented the highest potential for extracellular lipase production in OMW medium. Lipase productivity was improved by the medium supplementation with ammonium sulphate up to 6 g L-1, leading to 80% of COD degradation and 70% of total phenols reduction. The surfactant Tween 80 enhanced cell growth and COD degradation, but had a negative effect on lipase activity. Conclusions: Y. lipolytica has a great potential for OMW valorisation by its use as culture medium for biomass and enzymes production. The operating conditions that favoured lipase production differ from the conditions that improve COD reduction. © 2008 Society of Chemical Industry. [less ▲]

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See detailInteresterification of rapeseed oil with anhydrous milk fat and its stearin fraction. II. Modifications of melting properties
Giet, Jean-Michel ULg; Aguedo, Mario ULg; Hanon, Emilien ULg et al

in GCIRC Bulletin (2009), 25

Chemical and/or physical modification of oils and fats are commonly used by food industry to widen their range of applications (1,2). Lipase-catalysed interesterification of anhydrous milk fat (AMF) and ... [more ▼]

Chemical and/or physical modification of oils and fats are commonly used by food industry to widen their range of applications (1,2). Lipase-catalysed interesterification of anhydrous milk fat (AMF) and various vegetable oils is now a well documented procedure (3-7). The purpose of this technique is to produce original structured fats with properties different from a simple blending, that may be used as spreads or introduced into pastry. The new fats contain higher amounts of polyunsaturated fatty acids (PUFA) than butter, which provides health benefits (8,9). To our knowledge only a few authors associated AMF fractionation with blending and interesterification (10,11), although this combination may be used to increase the ratio of vegetable oil in blends and thus the PUFA content of the product. The compositional changes occurring during the lipase-catalysed interesterification of AMF/rapeseed oil (RO) and AMF stearin fraction (AMFSF)/RO blends were described in the first part of this study. In the present and second part are reported the resulting changes in physical properties, especially the melting behaviour through solid fat content (SFC), dropping point (DP) and fusion profiles by differential scanning calorimetry (DSC). [less ▲]

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See detailIntersterification of rapessed oil with anhydrous milk fat and its stearin fraction. I. Modifications of composition
Aguedo, Mario ULg; Giet, Jean-Michel ULg; Hanon, Emilien ULg et al

in GCIRC Bulletin (2009), 25

Milk fat in human diet is associated with cardiovascular diseases due to its high content in saturated fatty acids and cholesterol. Most vegetable oils are much healthier as they are rich in unsaturated ... [more ▼]

Milk fat in human diet is associated with cardiovascular diseases due to its high content in saturated fatty acids and cholesterol. Most vegetable oils are much healthier as they are rich in unsaturated fatty acids (1,2). Lipase-catalysed interesterification of oils and fats has arisen as an alternative to hydrogenation or chemical processes to produce margarine and shortenings (3), notably because they do not give rise to undesirable trans fatty acids (4). The enzyme exchanges fatty acids from one triglyceride to another, resulting in a redistribution of fatty acids species. For such a reaction, the lipase of Thermomyces lanuginosa was shown to be an efficient tool in solvent-free fat blends batches and micro-aqueous conditions (5). Enzymatic interesterification can thus be used to enrich “hard” fats with unsaturated fatty acids (6,7). As an illustration, rapeseed oil (RO) (a choice source of unsaturation-rich residues) was used in the present study to enrich anhydrous milk fat (AMF) with unsaturated C18 fatty acids (FA) (oleic, linoleic and linolenic acids). Comparatively, one “harder” fraction of AMF underwent the same reaction. The physico-chemical properties modifications induced by the reaction were followed. The compositional changes are reported in this first part and the consequent physical modifications are presented in a second part. [less ▲]

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See detailProduction of γ-Decalactone by a Psychrophilic and a Mesophilic Strain of the Yeast
Alchihab, Mohamed ULg; Destain, Jacqueline ULg; Aguedo, Mario ULg et al

in Applied Biochemistry and Biotechnology (2009), 158

Among 18 psychrophilic strains isolated near the Antarctic Station, the psychrophilic <br />strain Rhodotorula aurantiaca A19 was selected for its ability of growth and γ- <br />decalactone production at ... [more ▼]

Among 18 psychrophilic strains isolated near the Antarctic Station, the psychrophilic <br />strain Rhodotorula aurantiaca A19 was selected for its ability of growth and γ- <br />decalactone production at low temperatures. The effects of temperature, initial pH, and castor <br />oil concentration on the growth and γ-decalactone production by a psychrophilic and a <br />mesophilic strain of R. aurantiaca were investigated. The highest γ-decalactone production <br />in flasks (5.8 g/l) was obtained with the strain A19 at 14 °C and initial pH 7.0 in medium <br />containing 20 g/l castor oil. On the other hand, these factors did not affect the production of <br />γ-decalactone by the mesophilic strain. In fermentor, a γ-decalactone concentration of 6.6 g/l <br />was reached with the strain A19, whereas a maximum of 0.1 g/l was obtained with the <br />mesophilic strain. Our results suggest that the ability to synthesize γ-decalactone is a <br />particularity of the strain A19, since the mesophilic strain (no. 30645) produced small amounts, <br />and the other (no. 31354) did not exhibit this property. It is, to our knowledge, the first report of γ-decalactone production by R. aurantiaca and furthermore by a psychrophilic yeast strain. <br />Moreover, the amount of γ-decalactone obtained in fermentor with the strain 19 was on the <br />order of concentrations usually described in patents. [less ▲]

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See detailEnzymatic interesterification of anhydrous milk fat with rapeseed and/or linseed oil: oxidative stability
Giet, Jean-Michel ULg; Aguedo, Mario ULg; Danthine, Sabine ULg et al

in Journal of Agricultural and Food Chemistry (2009), 57(15), 6787-6794

Blends of anhydrous milkfat (AMF) and linseed oil (70/30), and AMF, rapeseed oil (RO) and linseed oil (LO), 70/20/10, were submitted to enzymatic interesterification. The oxidative stability of the blends ... [more ▼]

Blends of anhydrous milkfat (AMF) and linseed oil (70/30), and AMF, rapeseed oil (RO) and linseed oil (LO), 70/20/10, were submitted to enzymatic interesterification. The oxidative stability of the blends, the interesterified (IE) blends and IE blends with 50 ppm -tocopherol added as antioxidant were studied. Samples were stored in open flasks at 60°C, 25°C and 4°C, and periodically submitted to peroxide, p-anisidine, TBA value determination and UV measurement at 232 and 268 nm. The analysis of volatile compounds was carried out by SPME for the samples stored at 60°C. Peroxides appeared to be the only significant oxidation products after 12 weeks storage at 4°C. As expected, the binary blends (BB) were more sensitive to oxidation than the ternary blends (TB). The BB were associated with increased volatile emission compared to TB. Interesterification led to variable effects on the oxidation of fat mixtures, depending on composition and temperature (beneficial effect on BB, at both 25°C and 60°C, and a rather neutral effect on TB). The IE blends exhibited higher volatile release prior to ageing. A pro-oxidant effect of -tocopherol addition was observed at 25°C on both BB and TB. At 60°C, an antioxidant effect was observed on TB. [less ▲]

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See detailThe use of Macronet resins to recover γ-decalactone produced by Rhodotorula aurantiaca from the culture broth
Alchihab, Mohamed ULg; Destain, Jacqueline ULg; Aguedo, Mario ULg et al

Poster (2009)

The objective of this study was to recover the γ-decalactone produced by R. aurantiaca from the culture broth using three Macronet resins (MN-100, MN-102 and MN-202).

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See detailProduction and toxicity of γ-decalactone and 4-hydroxydecanoic acid from Rhodotorula aurantiaca
Alchihab, Mohamed ULg; Destain, Jacqueline ULg; Aguedo, Mario ULg et al

Poster (2009)

The objective of this study was to compare the production of γ- decalactone in different scales and to study the effects of 4- hydroxydecanoic acid and γ-decalactone on the growth of R. aurantiaca. The ... [more ▼]

The objective of this study was to compare the production of γ- decalactone in different scales and to study the effects of 4- hydroxydecanoic acid and γ-decalactone on the growth of R. aurantiaca. The effect of gum tragacanth on the production of γ-decalactone by R. aurantiaca was evaluated. [less ▲]

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See detailInteresterification of rapeseed oil with anhydrous milk fat and its stearin fraction
Aguedo, Mario ULg; Giet, Jean-Michel ULg; Hanon, Emilien ULg et al

Poster (2009)

Rapeseed oil (RO) (a choice source of unsaturation-rich residues) was used in the present study to enrich anhydrous milk fat (AMF) with unsaturated C18 fatty acids (FA) (oleic, linoleic and linolenic ... [more ▼]

Rapeseed oil (RO) (a choice source of unsaturation-rich residues) was used in the present study to enrich anhydrous milk fat (AMF) with unsaturated C18 fatty acids (FA) (oleic, linoleic and linolenic acids). Comparatively, one “harder” fraction of AMF underwent the same reaction. The physico-chemical properties modifications induced by the reaction were followed. The compositional changes are reported in this first part and the consequent physical modifications are presented in a second part. [less ▲]

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See detailInteresterification of rapeseed oil with anhydrous milk fat and its stearin fraction
Giet, Jean-Michel ULg; Aguedo, Mario ULg; Hanon, Emilien ULg et al

Poster (2009)

The compositional changes occurring during the lipase-catalysed interesterification of AMF/rapeseed oil (RO) and AMF stearin fraction (AMFSF)/RO blends were described in the first part of this study. In ... [more ▼]

The compositional changes occurring during the lipase-catalysed interesterification of AMF/rapeseed oil (RO) and AMF stearin fraction (AMFSF)/RO blends were described in the first part of this study. In the present and second part are reported the resulting changes in physical properties, especially the melting behaviour through solid fat content (SFC), dropping point (DP) and fusion profiles by differential scanning calorimetry (DSC). [less ▲]

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See detailEnrichment of Anhydrous Milk Fat in Polyunsatured Fatty Acid Residues
Aguedo, Mario ULg; Hanon, Emilien ULg; Danthine, Sabine ULg et al

Poster (2009)

Lipozyme TL IM was used in a solvent-free batch, microaqueous system for enzymatic interesterification of anhydrous milkfat (AMF) with linseed oil (LO) in binary blends and with rapeseed oil (RO) in one ... [more ▼]

Lipozyme TL IM was used in a solvent-free batch, microaqueous system for enzymatic interesterification of anhydrous milkfat (AMF) with linseed oil (LO) in binary blends and with rapeseed oil (RO) in one ternary blend. [less ▲]

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See detailCalorimetric study of milk fat/rapeseed oil blends and their interesterification products
Aguedo, Mario ULg; Giet, Jean-Michel ULg; Hanon, Emilien ULg et al

in European Journal of Lipid Science and Technology [=EJLST] (2009), 111(4), 376-385

Milk fat (MF) and rapeseed oil (RO) blends were analyzed by differential scanning calorimetry (DSC). It was shown that peak and onset temperatures can be used to determine the percentage of each fat in ... [more ▼]

Milk fat (MF) and rapeseed oil (RO) blends were analyzed by differential scanning calorimetry (DSC). It was shown that peak and onset temperatures can be used to determine the percentage of each fat in the blend and that the relative enthalpy of one peak assigned to low-melting triacylglycerols (TAG) can also be used to determine the percentage of RO in the blend. A linear relation was also established between IMF content of the blend and its dropping point (DP), indicating that DP can be linearly related with the above DSC data. A blend of MF/RO 70 : 30 (wt/wt) was then chosen as a model system for enzymatic interesterification (EIE). The applicability of DSC analyses to EIE products was checked and a correct correlation could be established between DSC values and the interesterification degree and DP. Among the data from the DSC profiles, the peak associated with low-melting TAG was the best indicator of the reaction course. In the same way, a high-melting MF stearin fraction was interesterified. with RO. In that case, onset temperatures and peak "a" were better reaction indicators than for the interesterified MF/RO blend. We therefore suggest that values from DSC endotherms could be used to monitor EIE of fat blends. [less ▲]

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See detailInteractions between bacterial surfaces and milk proteins, impact on food emulsions stability
Ly, M. H.; Aguedo, Mario ULg; Goudot, S. et al

in Food Hydrocolloids (2008), 22(5), 742-751

Bacteria possess physicochemical surface properties such as hydrophobicity, Lewis acid/base and charge which are involved in physicochemical interactions between cells and interfaces. Moreover, food ... [more ▼]

Bacteria possess physicochemical surface properties such as hydrophobicity, Lewis acid/base and charge which are involved in physicochemical interactions between cells and interfaces. Moreover, food matrices are complex and heterogeneous media, with a microstructure depending on interactions between the components in media (van der Waals, electrostatic or structural forces, etc.). Despite the presence of bacteria in fermented products, few works have investigated how bacteria interact with other food components. The objective of the present study was to determine the effects of the surface properties of lactic acid bacteria on the stability of model food emulsions. The bacteria were added to oil/water emulsions stabilized by milk proteins (sodium caseinate, whey proteins concentrate or whey proteins isolate) at different pH (from 3 to 7.5). The effect of bacteria on the emulsions stability depended on the surface properties of strains and also on the characteristics of emulsions. Flocculation and aggregation phenomena were observed in emulsion at pHs for which the bacterial surface charge was opposed to the one of the proteins. The effects of bacteria on the stability of emulsion depended also on the concentration of cations present in media such as Ca2+. These results show that the bacteria through their surface properties could interact with other compounds in matrices, consequently affecting the stability of emulsions. The knowledge and choice of bacteria depending on their surface properties could be one of the important factors to control the stability of matrices such as fermentation media or fermented products. © 2007 Elsevier Ltd. All rights reserved. [less ▲]

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See detailOlive mill wastewater valorization : use by non-conventional yeasts.
Gonçalves, C.; Lopes, M.; Aguedo, Mario ULg et al

in Nzihou, Ange; Lyberatos, Gerasimos (Eds.) Proceedings of the 2nd International Conference on Engineering for Waste Valorisation (2008)

The ability of the strains Yarrowia lipolytica and Candida rugosa to grow on Olive Mill Wastewater (OMW) based medium and to produce high-value compounds from OMW (such as enzymes), while degrading this ... [more ▼]

The ability of the strains Yarrowia lipolytica and Candida rugosa to grow on Olive Mill Wastewater (OMW) based medium and to produce high-value compounds from OMW (such as enzymes), while degrading this waste, was tested. Factors affecting cellular growth and OMW degradation were also studied, such as OMW composition, dilution and supplementation. OMW collected from 3-phase olive mill of the north region of Portugal were used and characterized chemical and biochemically. OMW with COD ranging from 100 g·L-1 to 200 g·L-1 were supplemented with yeast extract and ammonium chloride proportionally to its organic composition. Preliminary studies of OMW consumption were carried out in batch cultures of Y. lipolytica W29 and C. rugosa PYCC 3238. The strains were able to grow in the OMW used without dilution, to consume almost all of the sugars present in the media and to significantly reduce COD. Y. lipolytica W29 was less affected by operating conditions changes such as, stirring rate variation and OMW medium supplementation. [less ▲]

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See detailDevelopment of bioprocesses based in biphasic media involving the yeast Yarrowia lipolytica
Gomes, N.; Gonçalves, C.; Lopes, M. et al

in Ferreira, E.C.; Mota, M. (Eds.) Proceedings of the International Chemical and Biological Engineering Conference (2008)

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