Bioproduction of Natural Carotenoids by Dietzia maris and Rhodococcus opacus
Authors
Søbye, Anders ; Lund, Marie-Louise Knop
Term
4. term
Education
Publication year
2018
Abstract
This thesis investigates bioproduction of natural carotenoids, focusing on canthaxanthin from Dietzia maris DSM 43672 and astaxanthin from Rhodococcus opacus DSM 43250. Motivated by demand for natural pigments and concerns about chemical synthesis, the project tests a two-organism biosynthesis in which canthaxanthin is produced first and serves as a precursor to astaxanthin. Production and extraction were assessed using chloroform and edible sunflower oil, as well as a water-based sonication procedure; analytical methods included MS, NMR, NTA, and TLC. Sunflower oil extraction was unsuccessful. In contrast, sonication of D. maris cells in water generated vesicles (mean diameter 255.79 nm) that encapsulated canthaxanthin, achieving extraction yields of 152.72 µg/g. These canthaxanthin vesicles were fed to R. opacus, but no astaxanthin was detected during 24 hours of incubation. The findings suggest that water extraction of xanthophylls could offer a high-yield, solvent-free approach, provided the pigments can be separated from the vesicles.
Dette speciale undersøger bioproduktion af naturlige carotenoider med fokus på canthaxanthin fra Dietzia maris DSM 43672 og astaxanthin fra Rhodococcus opacus DSM 43250. Baggrunden er stigende efterspørgsel efter naturlige pigmenter og kritik af kemisk syntese. Projektet afprøver en to-organismes biosyntese, hvor canthaxanthin produceres først og fungerer som forløber for astaxanthin. Produktion og ekstraktion blev undersøgt med både kloroform og spiselig solsikkeolie samt en vandbaseret sonikationsprocedure; analyseteknikker omfattede MS, NMR, NTA og TLC. Solsikkeolie-ekstraktion var ikke succesfuld. Under sonikering i vand dannede D. maris derimod vesikler (middeldiameter 255,79 nm), som indkapslede canthaxanthin og gav udbytter på 152,72 µg/g. De producerede canthaxanthin-vesikler blev fodret til R. opacus, men der blev ikke detekteret astaxanthin inden for 24 timers inkubation. Resultaterne peger på, at vandbaseret ekstraktion af xanthophyller kan være en lovende, opløsningsmiddelfri metode, hvis pigmenterne efterfølgende kan frigøres fra vesiklerne.
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