This is a Concerted Action, set up to enable the various groups interested in production and use of Crambe to meet, exchange information and coordinate their work. This is an interesting crop, producing an oil with a high erucic acid content (53 to 67%). The most abundant triglyceride in the oil is 1,3 erucyl, 2-acyl glycerol. The symmetrical structure enables it to be treated with 1,3, specific lipases to give preparations containing around 90% erucic acid. This can be used as a building block for polymers. It can also be derivatised to produce material suitable for use as an adjuvant in herbicides and fungicides in order to reduce the pesticide dose. The crude oil, which is biodegradable, provides an alternative to mineral oil in many applications, such as use as a lubricant for chain saws. The crop also contains a glycosinolate (epi-progoitrine).
Glycosinolates are anti-nutritional compounds which may also find other uses since they have biocidal activity. This particular compound produces chiral cyanides which could be used for producing intermediates for fine chemicals, or be polymerised to form yarn to produce textiles of natural origin. The hull, which contains about 20% fibre, can be used for speciality paper or other sheet or film materials in combination with derived polymeric material. The realisation of these opportunities require the combined interest and expertise of breeders, agronomists, chemists and manufacturers. This continuing activity has already provided the means of extending knowledge in a number of areas as summarised below.
Crambe Abyssinica is a Cruciferae which was grown on 25.000 ha in the USA in 1993 with the aim of selling it in the future on the European market. Experiments mainly in the Netherlands (300 ha) have demonstrated that it can also be cultivated as a spring crop in Western Europe. Sowing dates and rates, plant depth and harvest practices are now well determined. However, pest and weed control are still under evaluation. Other trials will be conducted to increase the cultivation of this new crop especially on marginal and on set-aside lands. New varieties adapted to these situations are under evaluation.
Crambe appears to be a promising crop because of the many possible uses of its seed (pharmaceuticals, detergents, cosmetica, ceramics etc.).
In the concerted action, the interest will be focused on oil glucosinolate and fibre.
1. the oil has a higherucic acid (53-67 %) content.The most abundant triglyceride is 1,3- erucyl, 2-acyl glycerol. This symmetric structure allows the use of 1,3- specific lipases: and we aim to produce preparations containing about 90 % erucic acid. Erucic acid will be used as a building block for polymers. It will also be derivatized and the products will be tested as adjuvants for herbicides and fungicides in order to reduce pesticide doses. The crude oil which is biodegradable provides an alternative to mineral oils in many industrial applications. Its lubricating efficacy will be tested on chain saws. As it has a high smoke point, it will also be tested to harden special steels.
2. The only glucosinolate present is epi-progoitrine which will be tested biocidal activity against certain phytopathogenic insects and fungi.Upon hydrolysation, epi-progoitrine gives chiral cyanides (HBC) which have a high potential in organic chemistry and biotechnology for producing (1) intermediates for fine chemicals, (2) polymers for textile materials of natural origin. Different systems of bio reactors will be built up for optimization HBC production.
3. The hull which is about: 20 % rich in fibre will be used alone or with HBC polymers, for special papers and other materials.
Crambe abyssinica is a cruciferous plant which is already quite widely grown in the USA. It can be grown as a spring crop in the EU, although available varieties may not be optimised for European climates. Sowing dates and rates for seeding, cultivation and harvesting are established, but pest and weed control still require trials. The crop produces oil with a high erucic acid content, as well as containing a glycosinolate which can be used as a precursor of fine chemicals and polymers, and generating a residue (the hulls) which can be used as a source of cellulose pulp. At present improvements are required in yield and more work needs to be done on utilisation. The purpose of this project is to bring people with relevant experience and interest together in order to increase the exploitation of this non-food crop in the EU. A workshop on the subject is planned for Spring 1997.
Much of the seed used in Europe comes from the United States and may not be adapted to European climatic conditions.
Selection trials are being carried out, mainly in the Netherlands where 12 advanced genotypes are being assessed in comparison with the standard variety BelAnn. These showed large variations in emergence, plant development, infection by the fungus Alternaria, oil content and fatty acid composition.
Two genotypes were found to possess a low content of nervonic acid in the seed oil, as demanded for the production of erucamide. Infection by Alternaria was found to be a serious problem in growing Crambe. However, within the set of genotypes evaluated, some less susceptible genotypes were found. After two generations of self pollination, fully fertile plants were obtained from the interspecific cross between C.abyssinica and C. hispanica. Crossed plants were selected for a DNA content comparable to that of C. hispanica but with seeds retaining characteristics of C. abyssinica. These genotypes are probably suitable for introduction of the seed retaining characteristic into C. hispanica. Steps are being taken to register the variety "Mario".
It seems that the best area for Crambe cultivation is the Po Valley in Italy. Experiments are required to establish new areas suited to this crop.
At the moment, the quantities of seeds are not large enough to supply an oil mill. Hence, oil is extracted on the small scale by pressure.
The composition of the hull indicates that, in comparison with other lignocellulosic materials, the alpha-cellulose and ash content of the hulls are higher, whereas the hemicelluloses are lower. The lignin content was comparable to that of annual plants. A steam explosion process was very effective in the separation of cellulose, hemicellulose and lignin. Cellulose properties after steam explosion are promising for dissolving and derivatising and for use in paper production.
Oil in mechanical industries:
Contacts have been made with Italian and French companies involved in mechanical processes. Test have been encouraging, using oil in lubrication as well as in mixtures with petrol for two stroke engines.
Oils as an adjuvant in plant protection:
Crambe oil per se had no effect on spray retention by plant foliage, although formulated oil enhanced retention thanks to an associated emulsifier. Methyl erucate (the most abundant compound in methylated Crambe oil) performed slightly better than methyl oleate (methylated rapeseed oil) in enhancing the foliar penetration of pherimedipharm into barley. Formulated Crambe oil proved to be as efficient as Actipron, a reference mineral oil, in enhancing the efficacy of the herbicide quizalofop ethyl towards several graminaceous weeds. Crambe oil increased the penetration of the fungicide propiconazole into wheat leaves and influenced positively its translocation in the plant. In spite of trials dealing with 35 herbicides, no compound proved to be efficient in controlling volunteer rapeseed in the Crambe crop.
Tyrosinase catalysed hydrolysis of epi progoitrin at neutral pHs produces 5-vinyl oxazolidine 2 thione (VOT) as a derivative of the correspondent isothiocyanate by cyclisation. At acid pHs in the presence of Fe2+, the formation of nitrile (ENI) and epithionitrile is favoured. The latter, however, requires the presence of an epithiospecifer protein (ESP) which can also be isolated from Crambe seeds. Sufficient amounts of enantiomerically pure VOT and NI were prepared by immobilised myrosinase for carrying out tests in various fields of possible utilisation. Finally, VOT and NI were tested as anti-fungal compounds, as well as starting material for synthesising new bioactive molecules. VOT was also tested as an anti-tumour compound.
Funding SchemeCON - Coordination of research actions
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