Application de la biotechnologie à la biosynthèse de molécules : Production de gamma -décalactone par la levure psychrophile Rhodotorula aurantiaca A19

La gamma;-décalactone est un arôme se caractérisant par une odeur fruitée de type pêche. Lalittérature montre que plusieurs levures mésophiles sont capables de produire la gamma;-décalactone enutilisant l’huile de ricin, l’acide ricinoléique et ricinoléate de méthyle comme substrat. Ce travail s’estintéressé à l’optimisation de la production de gamma;-décalactone par une levure psychrophile à partird’huile de ricin. Dans la première partie de notre étude, après avoir comparé la production de gamma;-décalactone de 18 souches psychrophiles, la levure Rhodotorula aurantiaca A19 a été sélectionnée.Cette levure produit 4 lactones différentes : gamma;-octalactone, gamma;-nonalactone, gamma;-décalactone et gamma;-undécalactone. Parmi celles-ci, la gamma;-décalactone est le composant majeur à une concentration de 5,8g/L en fioles alors que les autres lactones ne dépassent pas 10 mg/L. La levure psychrophile A19 a étécomparée à d’autres levures mésophiles du même genre. La levure mésophile 30645 produit 0,06 g/Lde gamma;-décalactone alors que la levure 31354 ne produit aucune lactone. Les effets de plusieursparamètres physico-chimiques comme la température, le pH et la concentration en huile de ricin ontété étudiés en comparant la croissance cellulaire et la production de gamma;-décalactone par les souches A19et 30645. Nous avons également démontré que la forme R de la gamma;-décalactone est prédominante(99,6%). Dans la deuxième partie de ce travail, l’effet inhibiteur de la gamma;-décalactone a été mis enévidence sur sa production ; son précurseur l’acide 4-hydroxydécanoïque est beaucoup moins toxiqueque la gamma;-décalactone à l’égard de la cellule. L’ajout de la gomme tragacanthe (3 g/L) amélioresignificativement la production de gamma;-décalactone en jouant le rôle de piège. La production de gamma;-décalactone par R. aurantiaca a été développée en fermenteurs de 20- et de 100-L, les concentrationsatteintes sont respectivement 6,5 et 4,5 g/L. Les résultats obtenus dans la troisième partie suggèrentque la capacité de la levure psychrophile de produire la gamma;-décalactone est attribuée à la présence del’acyl-CoA oxydase et une thioesterase. Enfin, la gamma;-décalactone produite par R. aurantiaca peut êtreextraite du milieu de culture par adsorption sur trois résines Macronet hydrophobes (MN-100, MN-102 et MN-202)

Production of γ-decalactone by Yarrowia lipolytica : insights into experimental conditions and operating mode optimization

BACKGROUND γ-Decalactone production from ricinoleic acid biotransformation derived from the triglycerides in castor oil by Yarrowia lipolytica, has been widely described in literature in studies concerning lipidic metabolism that leads to lactones production, interactions of cells with the lipid substrate, toxicity of produced metabolites, selection of over-producing mutants and selection of environmental conditions. RESULTS In order to improve technological aspects of γ-decalactone production, oxygen transfer rate (OTR), cell density and oil concentration effects were investigated, in batch and step-wise fed-batch cultures of Yarrowia lipolytica W29. The best γ-decalactone concentration of 5.4 ± 0.5 g L-1 was obtained for batch cultures with 60 g L-1 of cells and substrate concentration. CONCLUSION The direct influence of aeration and agitation rates, thus of OTR, on production of γ-decalactone has been demonstrated. γ-Decalactone productivity of 215 ± 19 mg L-1 h-1 was obtained with 60 g L-1 of cells and castor oil concentration in batch and step-wise fed-batch cultures of Yarrowia lipolytica. The results obtained suggest that these two strategies are good alternatives for industrial production processes.The authors thank the Project 'BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes, REF. NORTE-07-0124-FEDER-000028' co-funded by the Programa Operacional Regional do Norte (ON. 2 - O Novo Norte), QREN, FEDER and Fundacao para a Ciencia e a Tecnologia (FCT) (SFRH/BD/63701/2009 PhD grant to Adelaide Braga) for the financial support provided and FCT Strategic Project PEst-OE/EQB/LA0023/2013

Biotechnological production of γ-decalactone, a peach like aroma, by Yarrowia lipolytica

The request for new flavourings increases every year. Consumer perception that everything natural is better is causing an increase demand for natural aroma additives. Biotechnology has become a way to get natural products. γ-Decalactone is a peach-like aroma widely used in dairy products, beverages and others food industries. In more recent years, more and more studies and industrial processes were endorsed to cost-effect this compound production. One of the best-known methods to produce -decalactone is from ricinoleic acid catalyzed by Yarrowia lipolytica, a generally regarded as safe status yeast. As yet, several factors affecting -decalactone production remain to be fully understood and optimized. In this review, we focus on the aromatic compound -decalactone and its production by Y. lipolytica. The metabolic pathway of lactone production and degradation are addressed. Critical analysis of novel strategies of bioprocess engineering, metabolic and genetic engineering and other strategies for the enhancement of the aroma productivity are presented.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684)

Production d’arômes de type lactone par des levures.

Production of aroma lactones by yeasts. Lactones are widely distributed in foods and beverages as aroma compounds. Their extraction from natural products is very expensive. Most of them can also be obtained in a chemical way, which is not well perceived by consumers. As an alternative, biotechnology proposes to use whole cells or enzymes to produce lactones by biotransformation or bioconversion of fatty acids. Different studies and patents have been conducted on that matter. In most cases, yeasts are the biological agent used. The main concerned lactones are γ- and δ-decalactones, γ-octalactone and γ-dodecalactone. This article describes lactones and their production by yeasts; particular attention will be devoted to the γ-decalactone

Production and toxicity of γ-decalactone and 4-hydroxydecanoic acid from Rhodotorula aurantiaca

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

The utilization of gum tragacanth to improve the growth of Rhodotorula aurantiaca and the production of γ-decalactone in large scale

The production of γ-decalactone and 4-hydroxydecanoic acid by the psychrophilic yeast R. aurantiaca was studied. The effect of both compounds on the growth of R. aurantiaca was also investigated and our results show that γ-decalactone must be one of the limiting factors for its production. The addition of gum tragacanth to the medium at concentrations of 3 and 4 g/l seems to be an adequate strategy to enhance γ-decalactone production and to reduce its toxicity towards the cell. The production of γ-decalactone and 4- hydroxydecanoic acid was significantly higher in 20-l bioreactor than in 100-l bioreactor. By using 20 g/l of castor oil, 6.5 and 4.5 g/l of γ-decalactone were extracted after acidification at pH 2.0 and distillation at 100 °C for 45 min in 20- and 100-l bioreactors, respectively. We propose a process at industrial scale using a psychrophilic yeast to produce naturally γ-decalactone from castor oil which acts also as a detoxifying agent; moreover the process was improved by adding a natural gum

Peroxisomal β-oxidation and Production of γ-decalactone by the Yeast Rhodotorula aurantiaca

γ-Decalactone is a fruity aroma compound resulting from the peroxisomal β-oxidation of ricinoleic acid by yeasts. During the β-oxidation of fatty acids, the acyl-CoA oxidase and thioesterase play an important role. In R. aurantiaca, we demonstrated the presence of partial gene sequences homologous to acyl-CoA oxidase and thioesterase involved in the pathways synthesis of γ-decalactone. This preliminary work is expected to characterize the relationship between the γ-decalactone production and the transcription of these partial gene sequences of R. aurantiaca probably involved in the oxidation of ricinoleic acid.<br /

Peroxisomal β-oxidation and Production of γ-decalactone by the Yeast Rhodotorula aurantiaca

γ-Decalactone is a fruity aroma compound resulting from the peroxisomal β-oxidation of ricinoleic acid by yeasts. During the β-oxidation of fatty acids, the acyl-CoA oxidase and thioesterase play an important role. In R. aurantiaca, we demonstrated the presence of partial gene sequences homologous to acyl-CoA oxidase and thioesterase involved in the pathways synthesis of γ-decalactone. This preliminary work is expected to characterize the relationship between the γ-decalactone production and the transcription of these partial gene sequences of R. aurantiaca probably involved in the oxidation of ricinoleic acid.<br /