FAIR-CT96-1946 Brassica carinata: The outset of a new crop for biomass and industrial non-food oil - CARINATA

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Final Report

Source: Final Report, March 2000

Consortium: The project was co-ordinated by Koipesol Semillas S.A., Sevilla (Spain) in partnership with Centro de Investigaciones Energdticas Medioambientales y Tecnologicas. Instituto de Energias Renovables. (CIEMAT), Madrid ( Spain), The Instituto Tecnico de Gestion Agricola S.A., Pamplona (Spain), ENEA Departamento Innovacione, Settore Biotecnologie e Agricoltura, Roma (Italy), Centre for Renewable Energy Sources, Biomass Department, Pikermi-Attiki (Greece), Croda Universal Ltd, Hull (United Kingdom), NOVAOL S.r.l., Milano (Italy). Universidad Politecnica de Madrid. Departamento de Produccion Vegetal, Botanica y Proteccion Vegetal, Madrid (Spain) and Consejo Superior de Investigaciones Cientificas, Instituto de Agricultura Sostenible, Cordoba (Spain).

Introduction

Rapeseed has become the third most important source of vegetable oil in the world. Modification of the fatty acid composition is currently an important objective, of plant breeding of this crop. Rapeseed oil has several advantages over petrochemical oils. These include homogenous composition, freedom from contaminants and biodegradability. Seed oils containing a high percentage of erucic acid is detrimental to food quality, but is a valuable feedstock for many industrial applications. Primary sources of erucic acid are the seed of traditional cultivars of rapeseed (Brassica napus).

Ethiopian mustard (Brassica carinata) has several desirable agronomic characteristics, such as resistance to a wide range of diseases and pests, which makes it a suitable candidate for semiarid regions. In fact, cultivars known as Mediterranean rapeseed types have been developed, which do not require cold for flowering and, in addition, they bloom in short day length conditions, allowing fall planting in the dry, warm Mediterranean climate.

The main objective of this project is the development of B. carinata as a new source of non-food raw material either for biomass to be processed into energy or oil from seeds which could be transformed in liquid biofuels or erucic acid derivatives for the plastic industry. Because of the special characteristic of this species, its production may serve for the diversification of the agricultural systems of cereals in the Mediterranean region of the European Union.

Objectives

The project has three main objectives.

• Evaluation of B. carinata as a source of non-food raw material for biomass and oil industrial uses. This objective has been divided in two research areas. The first one has been the evaluation of B. carinata biomass in thermal processes, for which the biomass storage conditions, the biomass preparations and the quality of this biomass have been studied. The second one, consisted of the evaluation of different types of oil found in B. carinata ( high and low erucic acid) to be used either in the production of biodiesel or as a plastic additive.
• Adaptation and productivity of B. carinata in Mediterranean agriculture. This activity included genotype evaluation and the identification of suitable regions and crop management for the production of B. carinata in the Mediterranean basin
• Plant breeding and seed production of B. carinata. It includes the selection of the genotypes for various purposes such as: Biomass reduction, oil production, oil type and low glucosinolate content. Among the breeding disciplines used are: classical breeding, mutagenesis, in vitro haplo-diploidisation and the development of hybrid cultivars.

Activities

The post harvest management study and characterisation of B. carinata biomass as a source for energy in thermal processes was analysed. The storage conditions of B. carinata biomass were studied, in comparison with B. napus biomass, in the experimental parcel sites where heaps were formed with biomass packs after harvesting of both crops. Different storage conditions of the heaps (uncovered, covered with plastic) have been tested. The analytical results of stored B. carinata and B. napus biomass, showed that biomass of both species has characteristics adequate for use in energetic processes after one year of storage. Heating values of the stored biomass did not significantly vary during the storage. Some microbial degradation (composting) occurred when the biomass water content was above 20% on a wet basis.

B. carinata, as a member of the Cruciferae, has a high sulphur content as compared to most forms of biomass. The average sulphur content in the samples studied has been around 0.5% on a dry basis. This can create a problem of S0₂ gas emissions above the normal levels found in the combustion of the biomass. The sulphur of B. carinata is significantly higher that of the varieties of B. napus studied.

The chlorine content has been found to be very variable in the samples analysed, varying from 0.1 to 1.3 % on a dry basis. In general, it can be considered that levels of this element in the fuel 0.8% can cause corrosion problems in the parts of the combustion installation, due to the formation of chlorine gas.

A tendency toward fouling and slagging by the B. carinata ash has been found to be linked to the high content of alkali elements, and to the ratio (R) of (Ca+Mg) to (K+Na). It has also been observed that the tendency at 950· C is low for values of R>one.

B. carinata biomass does not present particular problems for the pre-treatment operations prior to combustion. Comminution of the biomass if was needed, can be affected in a standard biomass hammermill with energy consumption that is significantly lower than that for woody biomass. Biomass chipping requires about 10-15 k Wt biomass. Storage of biomass outdoors for one year reduces very significantly the energy consumption at this stage.

The biodiesel study considered two important characteristics to identify its possible use in sectors where biodiesel is an alternative to heating and vehicle fuel. Two types of oil from B. carinata have been studied for the production of methyl esters by transesterification. One was characterised by a high content of erucic acid and the other was a low erucic acid type (LEAR).

The presence of unsaturated fatty acids affects negatively the oxidation stability of biodiesel. Of the two B. carinata oil samples the behaviour of the low erucic acid oil (LEAR) was significantly worse than that of the rapeseed methyl esters. In contrast, the high erucic oil (HEAR) was similar in behaviour to the rapeseed methyl ester, with a lower iodine number, despite a different lipid profile.

As far as the cold performance of the two methyl-esters is concerned, the LEAR variety is similar to rapeseed oil. The HEAR variety does not perform as well as rapeseed oil and in any case requires larger doses of additive in order to partially overcome this. In terms of a global rating, both products are of limited interest as a replacement to rapeseed oil especially as biodiesel is usually produced from rapeseed and sunflower oil blends, and sunflower oil in itself has poor stability vis-a-vis oxidisation and cold performance levels.

The oil BRK 121 line of B. carinata has been the best in comparison to HERO (high erucic rapeseed oil) for the production of the plastic additive crucamide. It is comparable in most respects with the erucic acid content at >50% being higher by about 10% than in HERO. In addition the contents of the sulphur and phosphorous amount found in the oil of some high erucic B. carinata lines grown in 6 locations is not a limitation for the use of B. carinata oil by the plastic additives industry.

The amide processing of the B. carinata oil progressed with no particular problem, yielding a product of equal quality in most respects with that erucamide currently being produced. The erucamide made from B. carinata oil was found to behave in a very similar way to standard Crodamide ER in terms of slip (reduction in the co-efficient of friction between two surfaces) and anti-blocking (unwanted adhesion between two film surfaces) performance in low density polyethylene (LPDE).

The most important point not in favour of the B. carinata oil being a ready substitute for rapeseed oil in the erucamide production, is the presence of higher amounts of polyunsaturated fatty acid with the subsequent reduced colour stability of the product due to the increased tendency to oxidation. Further study of the colour stability of the amide is required before a definitive statement can be made concerning the viability of B. carinata as an industrial feedstock for plastics additive manufacture.

The genotype evaluation and the identification of suitable regions for the production of R carinata has included several field trials in Spain, Italy and Greece both for biomass and seed production. From the evaluations made during 3 seasons, it was clear that Central and Southern Italy, Southern Spain and dry areas of Central and North of Spain and Central Greece, could be defined as an agroclimatic area where the growth of B. carinata shows a better adaptability than the rapeseed with respect to seed production.

This adaptability can be explained by the lack of silique shattering, a good drought tolerance and a high yield potential. Similarly the results indicated that Spain, Italy and Greece are an agroclimatic area where B. carinata shows a better adaptability than rapeseed also for biomass production.

Conclusions

From the studies carried out covering various factors that are involved in the agrononomic practices, the following conclusions can be drawn:

• Both for biomass production and seed yield, the optimum sowing date for B. carinata is in autumn, from middle September to middle October in wet and cool areas and from October to middle November in dry and hot areas of the Mediterranean basin.
• B. carinata is a very flexible species as refers to the number of plant/M² necessary to attain the highest yield. Nevertheless, the most suitable rate of sowing would appear to be around 8 kg/ha, to optimise the yield in all the climatic conditions.
• B. carinata is not particularly demanding in terms of nitrogen and sulphur, because, thanks to its tap root, it makes good uses of fertiliser remaining from pervious crops.
• B. carinata is a very interesting preceding crop for a cropping system of cereal, well adapted to soil with lower nutritional levels.

As a result of the plant breeding studies carried out during the last three years, it has been possible to increase the variability of B. carinata as far as biomass production and the specific fatty acid composition of the oil is concerned. In this way, some lines have been selected, that bloom late, and have a biomass yield of about 16 t/ha in wet areas and 10 t/ha in dry areas. Similarly new high erucic lines that have the special lipid profile required by the plastic industry have been obtained.

On the other hand, it has been impossible to obtain of low erucic acid lines with an oil content similar to rapeseed. An efficient system of microspore culture and mutagenesis ( ultraviolet light and ethylmethanesulfonate) has been established for B. carinata. This permits rapid identification of mutant lines, which is of great value for speeding up breeding programs.

The use of gamma irradiation of dry seed and UV and EMS in microspores of Brassica carinata induced genetic variants with reduced content of glucosinolates in the meal. In addition, individual plants with reduced glucosinolate content have been obtained by conventional breeding in segregant lines that came from inter-specific crosses among B. carinata, B. napus and B. juncea. The stability of this trait, both in segregant and in mutant plants, will be confirmed in the next generations.

The hybrid vigour potential among different crosses of B. carinata lines has been studied in two locations. The heterosis as regards grain and biomass yield and oil content is not present in all the crosses, indicating that this species does not have a good general combining ability for these traits. However, a high specific combining ability in some hybrid combinations was found both for biomass and for grain yield; this indicates that exploitation of hybrid vigour would be possible in B. carinata.

The development of B. carinata cytoplasmic male sterile has been carried out with different cytoplasm sources, such as Ogura, Ogura-INRA, Polima and Anand cytoplasms. Some lines have been converted in cytoplasmic male steriles. So far development of a fertility restorer is not completed.

As far as glucosinolate determination by HPLC is concerned, it has been found that control of the concentration of enzyme used is essential in order to obtain results that can be reproduced. Such problems may explain different results from different official laboratories. The use of glucotropeoline as internal standard is responsible for some discrepancy in the values obtained, that may be in some cases almost around 10 to 15%.