Cleavage of beta,beta-carotene to flavor compounds by fungi.
More than 50 filamentous fungi and yeasts, known for de novo synthesis or biotransformation of mono-, sesqui-, tri-, or tetraterpenes, were screened for their ability to cleave beta,beta-carotene to flavor compounds. Ten strains discolored a beta,beta-carotene-containing growth agar, indicating efficient degradation of beta,beta-carotene. Dihydroactinidiolide was formed as the sole conversion product of beta,beta-carotene in submerged cultures of Ganoderma applanatum, Hypomyces odoratus, Kuehneromyces mutabilis, and Trametes suaveolens. When mycelium-free culture supernatants from five species were applied for the conversions, nearly complete degradation of beta,beta-carotene was observed after 12 h. Carotenoid-derived volatile products were detected in the media of Ischnoderma benzoinum, Marasmius scorodonius, and Trametes versicolor. beta-Ionone proved to be the main metabolite in each case, whereas beta-cyclocitral, dihydroactinidiolide, and 2-hydroxy-2,6,6-trimethylcyclohexanone were formed in minor quantities. Using a photometric bleaching test, the beta,beta-carotene cleaving enzyme activities of M. scorodonius were partially characterized.
Zentrum Angewandte Chemie, Institut für Lebensmittelchemie der Universität Hannover, Wunstorfer Strasse 14, 30453 Hannover, Germany. zorn@lci.uni-hannover.de
H
H
Zorn
S
S
Langhoff
M
M
Scheibner
R G
RG
Berger
D000362:Agar; D001487:Basidiomycota / Q000201:enzymology; D001673:Biodegradation, Environmental; D003470:Culture Media; D005421:Flavoring Agents / Q000378:metabolism; D005658:Fungi / Q000145:classification / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D045792:Norisoprenoids / Q000378:metabolism; D010084:Oxidation-Reduction; D014835:Volatilization; D019207:beta Carotene / Q000378:metabolism*
D003470:Culture Media; D005421:Flavoring Agents; D045792:Norisoprenoids; D019207:beta Carotene; D000362:Agar; C008157:beta-ionone