Applied and Environmental Microbiology, Apr. 1998, p. 1226-1229
0099-2240/98/$04.00+0
Copyright 1998, American Society for Microbiology Vol. 64, No.
4
Production of the Carotenoids Lycopene, -Carotene, and Astaxanthin in the
Food Yeast Candida utilis
Yutaka Miura, Keiji Kondo, Toshiko Saito, Hiroshi Shimada, Paul
D. Fraser, and Norihiko Misawa
Central Laboratories for Key Technology, Kirin Brewery Co., Ltd.,
1-13-5, Fukuura, Kanazawa-ku, Yokohama-shi, Kanagawa 236-0004, Japan
Received 3 September 1997/Accepted 2 February 1998
The food-grade yeast Candida utilis has been engineered to confer a novel
biosynthetic pathway for the production of carotenoids such as lycopene,
-carotene, and astaxanthin. The exogenous carotenoid biosynthesis genes
were derived from the epiphytic bacterium Erwinia uredovora and the marine
bacterium Agrobacterium aurantiacum. The carotenoid biosynthesis genes were
individually modified based on the codon usage of the C. utilis
glyceraldehyde 3-phosphate dehydrogenase gene and expressed in C. utilis
under the control of the constitutive promoters and terminators derived
from C. utilis. The resultant yeast strains accumulated lycopene,
-carotene, and astaxanthin in the cells at 1.1, 0.4, and 0.4 mg per g (dry
weight) of cells, respectively. This was considered to be a result of the
carbon flow into ergosterol biosynthesis being partially redirected to the
nonendogenous pathway for carotenoid production.
And this is a second entry on yeast. Seems to me that it
would be easy to gut load brine shrimp or Daphnia with this
yeast to deliver the astaxanthin. George
Genetics of the astaxanthin producing yeast Phaffia rhodozyma
PhD-fellow: Jan Wery
Postdoc: Dr. Jan C. Verdoes
Supervisor: Prof. Albert J. J. van Ooyen
Project term: February 1992- May 1997
Sponsor: Gist-brocades NV
Introduction
Phaffia rhodozyma is a red basidiomycetous yeast that produces astaxanthin
as the main carotenoid. Astaxanthin is used as an additive in fish feed for
the coloration of cultivated salmon. In the past research on Phaffia was
mainly limited to the physiology of astaxanthin production. A physiological
approach to elucidate the biosynthesis pathway of astaxanthin has
limitations. Complementairy genetic studies are of great importance to
overcome these limitations.
Aim:
The main objectives of genetic research are obtaining insight in the for
the greater part unknown genetics of Phaffia.
Research:
At this moment a transformation system for Phaffia is developed. In this
system we use the G418 resistance gene as a selectable marker. A plasmid
was constructed in which this gene was placed downstream the Phaffia actin
promoter. (The Phaffia actin gene and promoter were isolated previously) A
part of the Phaffia ribosomal DNA was also cloned in this plasmid as a
stabilizing sequence. Transformation with the plasmid was carried out under
various conditions. Finally the electroporation of linearized plasmid
yielded reproducebly Phaffia transformants. The frequency of transformation
is rather low (1-5 transformants/g plasmid) and there are indications that
the actin promoter works poorly. Transformants carry the plasmid in high
copy number, whereas their resistancy to G418 is rather low. However it can
be concluded that a transformation system for Phaffia has been established.
Although this plasmid is less fit for the construction of a gene library in
Phaffia, it enables us to study t
he regulation of the carotenoid biosynthetic pathway of Phaffia in more
detail. The effect of the introduction of genes from carotenoid
biosynthetic pathways of other microorganisms will be studied. Currently we
are searching for a stronger promoter upstream the G418 resistance marker
to optimize transformation frequencies.
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a.. Wageningen Agricultural University
b.. Department: Department of Food Science, Division of Industrial Microbiology
c.. Address: P.O. Box 8129, 6700 EV Wageningen, The Netherlands
d.. Telephone: +31 (0)317-483393
e.. Telefax: +31 (0)317-484978
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Updated at: 15/11/1996 by MdW
Comments and questions to: Martin de Wit.