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GENETIC ENGINEERING OF CAROTENOID METABOLISM: A NOVEL ROUTE TO VITAMINS, COLORS AND AROMAS FOR THE EUROPEAN MARKET

Objective



Carotenoid market, uses and health benefits
Carotenoids are terpenoid pigments very widespread in nature. They are industrially
used as highly safe colourants of food and cosmetic preparations. In addition,
beta-caroten is the dietary precursor of vitamin A. The market for purified
carotenoids is growing rapidly and it already exceeds 100 million US$/yr. Over
90 % of the market is covered by expensive, chemically synthesized carotenoids,
the remainder being obtained through fermentation of fungi or extraction from
plants (e.g. paprika extract).

Carotenoid metabolites play also a role in aroma : the flavour of many plant
products, such as tomato and saffron, is due to volatile derivatives of the
xanthophyll oxidative metabolism. Consumers are becoming more
health-conscious, increasing the potential consumption of antioxidant carotenoids
in the diet. USDA and the US National Cancer Institute recommend a daily intake
of 4-6 mg/day beta-carotene. In developed countries we eat between 1 and 1,5
mg/day (Lachance, 1988), and in some third world countries this figure is below
0.5 mg/day. For the above reasons, the biotechnological production of carotenoid
metabolites has a high potential impact on the market of speciality products. The
same approach could solve the severe carotene shortages in some countries.

Measurable objectives
1. To enlarge the repertoire of available genes encoding specialized steps in
carotenoid metabolism, that would allow the engineering in crops or
microorganisms of high value compounds;
2. To produce, by genetic engineering of widely cultivated crops and
filamentous fungi (tomato, Phycomyces), high added value carotenoid
metabolites involved in food colour and aroma (zeaxanthin, astaxanthin,
crocetin, picrocrocin). To improve, by genetic engineering, the beta-carotene
(provitamin A) content of main crops (potato, rice);
3. To preliminarily assess the nutritional and agronomic qualities of the
engineered crops and fungi.

State of the art
Great progress has been made recently in the isolation of plant genes controlling
carotenoid biosynthesis (Bartley et al., 1994) (Fig. 1). All genes controlling the
synthesis of beta-carotene have been cloned and their regulation is under study.
Considerable part of this progress has been achieved under a current, EU-financed,
Biotechnology project which involves several world leading groups studying
carotenoid biosynthesis, including 5 of the 8 partners in the present proposal.
Techniques for the transformation of the proposed plants and fungi are well
developed. Preliminary modification of carotenoid metabolism in tomato, rice and
Phycomyces through genetic engineering has been achieved by some the partners.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Ente per le Nuove Tecnologie l'Energia e l'Ambiente (ENEA)
Address
Via Anguillarese 301
00100 Santa Maria Di Galeria Roma
Italy

Participants (7)

ALBERT-LUDWIG-UNIVERSITÄT FREIBURG
Germany
Address
Schänzlestr., 1
79104 Freiburg
C.N.R.S.
France
Address
Rue Du General Zimmer, 12
67000 Strasbourg
D.J. VAN DER HAVE B.V.
Netherlands
Address
Van Der Haveweg, 2
4411 RB Rilland-bath
ROYAL HOLLOWAY AND BEDFORD NEW COLLEGE
United Kingdom
Address
Egham Hill
TW20 0EX Egham, Surrey
SWISS FEDERAL INSTITUTE OF TECHNOLOGY ( ETH ZÜRICH)
Switzerland
Address
Universitätstraße, 2
Zürich
UNIVERSIDAD DE SEVILLA
Spain
Address
Apartado 1095
41080 Sevilla
UNIVERSITÄT HOHENHEIM
Germany
Address
Fruwirthstr., 12
70599 Stuttgart