Etude comparative du catabolisme de l'acide ricinoléique chez les levures du genre Sporidiobolus : mise en évidence et caractérisation du système béta-oxydant impliqué

*INRA Centre de Dijon (FRA) Diffusion du document : INRA Centre de Dijon (FRA) Diplôme : Dr. d'Universit

Etude comparative du catabolisme de l'acide ricinoléique chez les levures du genre Sporidiobolus : mise en évidence et caractérisation du système béta-oxydant impliqué

*INRA Centre de Dijon (FRA) Diffusion du document : INRA Centre de Dijon (FRA) Diplôme : Dr. d'Universit

Etude comparative du catabolisme de l'acide ricinoléïque chez les levures du genre Sporidiolus (mise en évidence et caractérisation du système béta-oxydant impliqué)

Les levures du genre Sporidiobolus sont utilisées pour la production de g-C10 (arôme pêche) par dégradation d'acide ricinoléique. Parmi 4 espèces du genre, seules 2 produisent la g-C10 en forte quantité, alors que toutes dégradent le substrat. Nous avons recherché les intermédiaires de la ß-oxydation du RCoA sur extraits de Sporidiobolus in vitro. Des différences métaboliques ont été mises en évidence entre ces levures. Sp. Ruinenii et Sp. Pararoseus ont été prises comme modèles pour lier ces résultats à l'organisation des enzymes impliquées. Ainsi, la protéine (PMF) portant deux activités de la b-oxydation (énoyl-CoA hydratase et 3-hydroxyacyl-CoA déshydrogénase) a été partiellement purifiée et se localise dans les peroxysomes et le cytosol de Sp. Ruinenii. Chez Sp. Pararoseus outre une PMF similaire, un complexe portant l'acyl-CoA déshydrogénase, la thiolase et une 3-hydroxyacyl-CoA déshydrogénase serait impliqué dans la b-oxydation. La localisation de ce système est discutée.The yeast of the genus Sporidiobolus are used for g-C10 (peach flavour) production through ricinoleic acid degradation. Among 4 species in the genus, only 2 produce important quantity of g-C10, whereas all degrade the substrate. We searched for RcoA b-oxidation intermediates by extracts of Sporidiobolus in vitro. Metabolic differences were shown between the yeast. Sp. ruinenii and Sp. pararoseus were chosen as models for trying to link these results to the organisation of involved enzymes. The protein (MFP) bearing two ß-oxidative activities (enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase) was partially purified and is located into sp. ruinenii peroxysomes and cytosol. in sp. pararoseus in addition to a similar mfp, a complex exhibiting acyl-coa dehydrogenase, thiolase and a 3-hydroxyacyl-CoA dehydrogenase activities would be involved in b-oxidation. The localisation of this complex is discussed.DIJON-BU Sciences Economie (212312102) / SudocSudocFranceF

Microbial production of flavors for the food industry. A case study on the production of gamma-decalactone, the key compound of peach flavor, by the yeast Sporidiobolus sp

International audienc

Microbial production of 4-hydroxybenzylidene acetone, the direct precursor of raspberry ketone

International audienceAims: To investigate the enzymatic aldol reaction between acetone as a donor and 4-hydroxybenzaldehyde as a receptor to generate 4-(4-hydroxyphenyl)-but-3-ene-2-one or 4-hydroxybenzylidene acetone, the direct precursor of 4-(4-hydroxyphenyl)-butan-2-one or raspberry ketone, using different species of filamentous fungi and bacteria. Methods and Results: Different classes of micro-organisms were tested in a medium containing mainly acetone and 4-hydoxybenzaldehyde. Of the micro-organisms tested, only bacteria were able to synthesize significant amounts of 4-hydroxybenzylidene acetone, ranging from 15 to 160 mg l(-1) after 21 h of bioconversion, as a function of the bacteria tested. Conclusions: The biological production of 4-hydroxybenzylidene acetone has been described with bacteria possessing 2-deoxyribose-5-phosphate aldolase (DERA, EC 4.1.2.4). This result suggests that DERA is involved in the catalytic aldolization of precursors for the production of 4-hydroxybenzylidene acetone. Significance and Impact of the Study: Raspberry ketone or frambinone represents a total market value of between e6 million and e10 million. The possibility of producing its direct precursor through a simple process using bacteria is of considerable interest to the flavour market and the food industry as a whole. This paper broadens the spectrum for the use of aldolase to achieve the biological synthesis of compounds of interest

Advantages and limitations of online communities of patients for research on health products

International audienc