PRODUCTION AND IMPROVEMENT OF HYDROCARBONS IN LATICIFER PLANTS
PRODUCTION AND IMPROVEMENT OF HYDROCARBONS IN LATICIFER PLANTS V1A.66 A. Kumar, V.R. Kumar, S. Parveen, V.P.S. Shekhawat, A. Kotiya Department of Botany, University of Rajasthan, Jaipur – 302 004, INDIA Phone : 0141-2711654 (Off.) 0141-2654100 (Resi.) E-mail : email@example.com Biomass currently supplies about a third of the developing countries’ energy varying from about 90% in countries like Uganda, Rawanda and Tanzania, to 45 percent in India, 30 percent in China and Brazil and 10-15 percent in Mexico and South Africa. The crucial questions are whether the two billion or more people who are now dependent on biomass for energy will increase. The fact that 90 percent of the worlds population will reside in developing countries by about 2050 probably implies that biomass energy will e with us forever. Tropical deforestation is currently a significant environment and development issue. At the global level, according to recent estimates by FAO the annual tropical deforestation rate for the decade 1981 to 1990 was about 15.4 million h (Mha) (Anonymous 1995). According to the latest data published in 1994, for the assessment period 1989-1991, the total area under forests is 64.01 Mha accounting for 19.5 percent of India’s geographic area (Anonymous, 1995). At present there is hardly 0.4 percent forest below 25cm rainfall zone and 1.3 percent above 30 cm rainfall zone. There is rapid depletion of forest products and in order to provide alternative energy sources a change is needed in conventional forestry management. Four broad categories of biomass use can be distinguished – a) basic, e.g. food, fiber, etc.; b) energy, e.g. domestic and industrial; c) materials, e.g. construction and d) environmental and cultural, e.g. the use of the fire. Biomass use through the course of history has varied considerably, greatly influenced by two main factors population size and resource availability. Since the annual photosynthetic production of biomass is about eight times the world’s total energy use and this energy can be produced and used in an environmentally sustainable manner, while emitting net CO2, there can be little doubt that this potential source of stored energy must be carefully considered in any discussion of present and future energy supplies. The fact that nearly 90 percent of the worlds population will reside in developing countries by a bout 2050 probably implies that biomass energy will be with us forever unless there are drastic changes in the world energy trading pattern. Planting of more trees in forest reserves for reducing global warming has been universally accepted, the idea being that carbon-dioxide absorption would continue until the trees mature say for 40 to 100 years. Although it is recognized that this is not a permanent solution this “carbon sequestration” strategy buy time to develop alternative energy sources. The impact of biomass utilization on the energy flow of ecosystems The measure most widely used to characterize the energy flow of ecosystem is net primary production (NPP). The NPP is the biomass production of green plants in the certain region within one year. Societies greatly influence the amount of NPP actually available for ecosystem processes on their territory : (1) They influence the productivity, i.e. the NP per m and year of ecosystems, e.g. construction of buildings roads etc. and thus preventing NPP altogether, but also by agriculture and forestry and (2) they harvest a significant proportion of the biomasswhich annually grows on their territory. Biomass use however, tends to increase the societal appropriation of net primary production (NPP) and thus leads to major disturbances of the natural energy flow of ecosystem. These two processes can be appraised with a single indicator which is called “appropriation of NPP”. Empirical studies show that current level of NPP appropriation is significant. Scientists have estimated the worldwide appropriation of NPP to fall within the interval of 25 to 40 percent. NPP appropriation may be defined as the difference between the NPP of the potential natural vegetation (NPPo, i.e. the vegetation that would prevail in the absence of human interference) and the amount of biomass currently available in ecological cycles (NPP1). For appraisals of NPP appropriation of following conventions are useful : The NPP of the actual vegetation is denoted as NPP act harvest as NPP h Total appropriation can be calculated with the formula : NPP a = NPPo-Npp1 with NPP1 = NPP act – NPPh Two processes contribute to appropriation; (1) human induced changes in productivity of ecosystems (e.g. constructions of buildings and roads) and (2) biomass harvest by agriculture and forestry. The current level of NPP appropriation is already rather high and there are strong indications that the appropriation of NPP contributes to the reduction of biodiversity. This can be interpreted as follows : The NPP appropriation is high, where climate and soil conditions allow for a high NPP of the potential vegetation and low in the rather unproductive regions. Thus NPP appropriation is high in fertile, intensively used agricultural areas and low in the Alps where initial productivity is low. NPP appropriation significantly alters the energy flow of natural ecosystems and may be seen as an indicator for the intensity of human interventions into natural ecosystem processes. NPP is the main energy input for al heterotrophic food chains. Obviously then the harvest of 100 percent of NPP is unsustainable, since this would leave no room for any wildlife species and would result in the extinction of most heterotrophic organism such as animals and fungi. It is true that a reduction of energy flow reduces the length of food chain then a second assertion of Hutchinson may also prove correct, namely that the amount of energy available exerts an important influence on species diversity. In the last two decades this idea experienced a renaissance as the so called species energy theory of biodiversity. In short the species energy theory predicts that the number of species which can inhabit a certain environment increases with the amount of energy available, conversely the number of species will decrease if energy flow is reduced. Thus biomass is a scarce resource which should be used sparingly from an ecological point of view. If biomass should play a major role for CO2 reduction, the efficacy of biomass use has to be increased. This can be achieved by focusing on a “cascade utilization of biomass” the use of biomass as raw material and as energy carrier should be optimized in an integrated manner. The rationale behind this is that if biomass is used for energy generation which had been previously used for some other, this will not contribute to an increase of NPP appropriation. The development of optimal biomass utilization cascades requires that conflicts of interest have to be solved. According to the widely held view of many environmental experts, its utilization should be encouraged for several purposes. * Biomass should be used instead of fossil energy carriers in order to reduce i) CO2 emissions ii) the anticipated resource scarcity of fossil fuels and iii) need to import fuels from abroad. There are important arguments in favour of these recommendations. Biomass is indeed a “renewab le” resource as long as agriculture does not deplete soil fertility and forestry obeys some “sustainability rules” dating back to 18th century when the German forester Von Carlowitz coined the notion of “sustainable forestry” (“nachhaltige forstwirtschnaft”). Biomass utilization could thus contribute to a “closed cycle.” The utilization of biomass contributes to significant anthropogenic alterations of the natural energy flow of ecosystem. The chemically stored energy which plants produce in the process of photosynthesis is the main energetic basis of all food chain. By using biomass, societies alter the amount of energy available for ecological energy flows and change the quality of the available biomass as this intervention is likely to contribute to species loss and is highly relevant with respect to many important ecosystem properties. The agreement at Kyoto in December 1997 signals political acceptance among the industrialized countries that carbon dioxide (CO2) emissions must be reduced. Renewable energy and in particular biomass has a vital role to play in climate stabilization. Another major reason why the use of biomass for energy will increase is the growth in energy demand in developing countries, where affordable alternatives are often unavailable. The potential resource for bioenergy is large, especially in riche countries where there is a surplus land and many low latitude countries specially where high biomass yields are possible (Mittelbach et al., 1983). Optimization of Biomass use – Development of Optimal Biomass Utilization Cascades It is apparent that significant increases of the biomass harvest of industrialized countries should not be considered a sustainable option for alleviating other environmental problems as for example resource scarcity or global warming. Thus if biomass utilization should play a major role in environmental policy its efficiency has to be increased. The biomass harvested should be used as effectively as possible in order to contribute to as much as possible to the substitution of environmentally detrimental materials and fuels. This could be possible by a strategy of integrated optimization of material and energy uses of biomass which may be called “cascade utilization of biomass”. The use of biomass as an energy carrierr and as a raw material are usually treated separately and the potential for entire are also often estimated independently of each other. Biomass use is often “optimized” only over parts of its supply chain of applications instead an optimization of over the whole “cascade” of application. Optimizing biomass use to reflect the different characteristics of different biomass sources and of the different sectors of the economy’s requirements for biomass of particular physical characteristics would offer significant efficiency gains. For this it is essential to take into account thequality of the biomass required. For example if biomas (wood is for the production of press boards) the properties of the fibers will be decisive. Other properties, e.g. calorific values are important, if biomass is used for energetic purposes. From microeconomics standpoint it is irrelevant whether the biomass used for energy generation was specially grown for this purpose, or whether it results as a waste from other processes of the economy. All the matters are the costs, the quality and the security of supply. However the origin of biomass is a key factor in whether its use constitutes an integral part of sustainable development strategy. Besides this the availability of the land for raising the biomass is another important factor. If the biomass has to be grown on the arable land, then the competition and costs of food vs fuel production shall be grossly increased. India with its vast expanse of wasteland unsuitable for agricultural production (nearly 180 million ha) could be considered for economically viable production of biofuels. With the cheap labour available in rural sector the limitation of adequately supply of water could be another factor. Almost 3 cattles per head offers formidable force of biomass consumers to combat with available ordinary means. The options are limited under these conditions to search and study the vast number of unexplored plant species as out of 260000 plant species only 10,000 or so have been exploited during the course of human civilization. Biomass may be used as a raw material as food stuffs and as an energy source, and biomass covers not only wood products but other plants and plant residue and biogas. The development of optimal utilization plans, therefore is a complex task which should include the following steps : 1. Status quo analysis : Appraisal of the current level of NPP appropriation and biomass utilization patterns. 2. Identification of untapped potential for the reuse or recycling of biomass products (e.g. paper products, chip boards, etc.) and for the energetic use of biomass wastes and residues. 3. Identification of technologies for these applications. 4. Analysis of conflicts of interests between competing utilization paths and conflicting criteria (economic, ecological, social and development of methodologies) which may be useful to solve them. 5. Development of policy instruments to foster the cascadic use of biomass (technological development, pilot projects, subsidies, counseling programmes, taxes, etc.). The evaluation of biomass potential has to be carried out on a regional level. This must consider the entire production chain of the various biomass use paths from primary production to waste, including the treatment stages, transport, waste treatment and disposal. The results may greatly differ depending on natural as well economic variables : Climatic geomorphology, the regional structure of agriculture, forestry, and the biomass using sector of the economy. Some examples for biomass which currently is used only partially or not at all are residues of sugar cane (potential use : biogas), dung and overstood fodder in agriculture (pot post) separately collected organic wastes (production of biogas instead of compost) saw dust and other residues from saw mills and the timber industry (combustion in small cogeneration plants or district heating system). Of course, many of these possibilities are used to some extent today but there appears to be no consistent policy for the optimization of these uses. Such investigations may also reveal the necessity to change production processes at an earlier stage of the biomass utilization chain. Laticiferous plants with their rich hydrocarbon contents offer such potential plant systems which on one hand, due to their water conversion ability they thrive on limited amount of water, produce sufficient biomass and are unpalatable to the cattle folk due to their sticky latex. Degraded and denunded soils are no hindrance to their growth. Solar energy Solar energy accumulated under the earth in the form of fossil fuels since the inception of life, accounts for more than 93 percent of the world’s consumption of energy, of which the share of oil is about 56 percent. With the present rate of consumption of 65 million barrel of crude oil per day and projected estimates, the present crude reserves may badly depleted within next 40 years. The energy costs for extracting the residual oil shall far exceed the energy for extracting crude oil after that period. The depletion of fossil fuels has temporarily ceased to be a defining issue in global energy, with the discovery of new oil and gas reserves, and the large existing coal reserves. Nonetheless the transition of renewable energy supply and greater efficiency in the use of energy has never been more urgent due to the threat of global climate change caused largely by the burning of fossils. The argument at Kyoto in December 1997 signals political acceptance among the industrialized countries that the carbon dioxide (CO2) emissions must be reduced. Renewable energy and in particular biomass has a vital role to play in climate stabilization. Another major reason why the use of biomass for energy will increase is the growth in energy demand in developing countries, where affordable alternatives are often unavailable. Biomass as energy source The world derives one fifth of its energy from renewable resources – 13-14 percent from biomass and 6 percent from hydrocarbon. In the case of biomass this represents about 25 mboe/day (55EJ/year). Since the annual photosynthetic production of biomass is about eight times the worlds total energy use and this energy can be produced and used in an environmentally sustainable manner, while emitting not net CO2, there can be little doubt that this potential source of stored energy must be carefully considered in any discussion of present and future energy supplies. The fact that nearly 90 percent of the worlds population will reside in developing countries by about 2050 probably implies that biomass energy will be with use foreover unless there are drastic changes in the world energy trading pattern. A recent World Bank report conclude that “Energy policies will need to be as concerned about the supply and use of biofuels as they are about modern fuels. … They must support ways to use biofuels more efficiently and in sustainable manner” (World Bank, 1996). Biomass resources are potentially the world largest and sustainable energy source, a renewable resource comprising 220 billion oven dry tones (about 4500 EJ) of annual primary production. The annual bioenergy potential is about 2900 EJ though only 270EJ could be considered available on sustainable basis at competitive prices. Most major energy scenarios recognize bionenergy as an important component in the future worlds energy. Projections indicate the biomass energy use to the range of 85 EJ to 215 EJ in 2025, compared to current global energy use of about 400 EJ of which 55 EJ are derived from biomass (Hall and Rosillo-Calle, 1998). Utilization of biomass for energy and industry allows a significant quantity of hydrocarbons to be consumed without increasing the CO2 content of the atmosphere and thus makes a positive contribution to the greenhouse effect and to the problems of “global change” as occurs in both industrialized and developing countries. Further and advantages from utilization of biomass include : liquid fuels produced from biomass contain no sulphur, thus avoiding SO2 emissions and also reducing emission of Nox. Modern bioenergy technologies and biofules are relatively benign from environmental view point and produce very little pollution if burned correctively and completely Mittelbach et al., 1983). The creation of new employment opportunities within the community and particularly in rural areas will be one of the major social benefits from the exploitation of biomass for energy, industry and environment. The specific research work carried out in the areas of biomass production and utilization in less fertilize areas will provide satisfactory answers to the double challenge of energy crisis and forced deforestation in the country in general and semiarid and arid regions of Rajasthan in particular. In developing countries it is the most important source of energy (35 percent of total) for the three quarters of the worlds population which lives in them. In some developing countries biomass provides 90 percent or more of total energy. Biomass is also used for energy in some industrialized countries such as the United States (4 percent equivalent in energy content to 1.4 million barrels of oil per day), Austria (13 percent), and Sweden (17 percent). Since the annual photosynthetic production of biomass is about eight times the worlds total energy use and this energy can be produced and used in an environmentally sustainable manner, which emitting no net CO2, there can be little doubt that this potential source of stored energy must be carefully considered in any discussion of present and future energy supplies. Vegetable biomass in the form of wood or dry littler was for a long time the only fuel providing external energy for cooking and later manufacturing. Due to such factors as overgrazing and deforestation, fuel supplies from biomass are now in a critical state in many developing countries in which the mass of population relies on them. To meet the challenge of the increasing demand for energy, alternative sources of energy, a new technologies for exploiting the available biomass resources have been developed. During recent years, attempts have been made to raise bioenergy plants under semiarid conditions in different parts of the world. Practical Approach The most practical way to develop such system is to make use of land resources that are presently under used or completely unsuitable for conventional agriculture. Most of the plants of desert area produce economically important highly reduced organic compounds such as low molecular weight hydrocarbons. Although they have overall growth rate lower than that of conventional crops, these plants allow improved water economy by producing a greater energy content per unit of dry weight biomass. Thus the most important logical approach for bioenergy production is to develop proper agrotechnology for the plants that produce oils and hydrocarbons having high energy value. However the work on the development of suitable agrotechnology for these plants was initiated in 1980 (Kumar, 1984). Certain potential plants were selected and attempts were made to develop proper agrotechnology for their large scale cultivation. Initially work was initiated at 5 ha and subsequently extended to 50h Energy Plantation Demonstration Project Centre (EPDPC) (Kumar, 1984b; Roy and Kumar, 1989, 1995 Kumar and Roy, 1996). Certain potential plants were selected and attempts were made to develop agrotechnology for their large scale cultivation (Kumar 1984b, c, 1994a, b, 1998; Kumar et al., 1995, 1998; Roy, 1998). The potential plants could be characterized under the following categories i) hydrocarbon yielding plants ii) high molecular weight hydrocarbon yielding plants, iii) non edible oil yielding plants, iv) short rotation fast growing energy plants, vi) hill plants growing on Aravallis. Hydrocarbon yielding plants included : i. Euphorbia lathyris Linn. ii. Euphorbia tirucalli. Linn. iii. Euphorbia caducifolia Haines. iv. Euphorbia nerifolia Linn. v. Pedilanthus tithymalides Linn. vi. Pedilanthus tithymalides Linn. vii. Calotropis procera (Ait.). R. Br. viii. Calotropis gigantea (Linn) R. Br. High molecular weight hydrocarbon yielding plants Parthenium argentatum Linn 1. Non edible for yielding plants Jatropha curcas Simmondsia chinenesis Short rotation energy plants Tecomella undulata Prosopis juliflora Pithocellobium dulce Azadirachta indica Dalbergia sisso Acacia tortilis Holoptelia integrifolia Parkinsonia aculeata Cassia siamea Albizzia lebbek Acacia nilotica A 50 ha bioenergy plantation demonstration project centre has been established in the campus of the University of Rajasthan to conduct the experiments on large scale cultivation of selected plants with the objective of developing optimal conditions for their growth and productivity, besides conserving the biodiversity. Considerable work has been carried out on these plants (Kumar, 1987, 1994b, c, 1995, 1996, Kumar and Roy, 1996; Roy and Kumar, 1998, 1990). Investiations on several plant species have been carried out at our centre including Parthenium argentatum (Bafna and Kumar, 1983), Euphorbia lathyris (Garg and Kumar, 1987a, 1987b, 1989a, 1989b, 1990; Kumar and Garg, 1995). Euphorbia tirucalli (Kumar and Kumar, 1985, 1986, 1986). Euphorbia antisyphilitica (Johari et al., 1990, 1991, Johari and Kumar 1992, 1993a, 1995) Pedilanthus tithymaloides (Rani et al, 1991; Rani and Kumar 1994a); Calotropis procera (Rani et al, 1990); Euphorbia neeriifolia and E. caducifolia (Kumar 90, 1994) Jatropha curcas (Roy, 1990, 1991, 1992b, 1994. 1996;; Roy and Kumar 1990) and Simmondsia chinensis (Roy, 1992a). Propagation In general these plants are easily propagated through cuttings. The optimum period for raising cuttings in June-July and March-April. Cuttings from apical and middle portions of E. antisyphilitica exhibit 100 percent survival rate, while non of the cuttings from the basal portions survived. Spacing among the planted cuttings is also a crucial factor for survival of cuttings. It was noted that initially upto a period of two months the survival percentage was maximum in closest planting density. Regarding environmental variations. March to October period was best suitable for E. antisyphilitica because of linear increase in growth was recorded in this period (Kumar 1990). Overall growth and productivity was lowest in the winter months from November to February. Higher accumulation of hexane extractable corresponded with higher temperatures of summer season (Johari and Kumar, 1992). Edaphic Factors Among different soil types, sand was best for the growth of E. lathyris (Garg and Kumar, 1990) and P. tithymaloides (Rani et al, 1991) while red loamy soil was best for E. antisyphilitica. When different combinations of these soil types were made biomass of E. antisyphilitica was maximum in red+sand+gravel (Johari et al., 1990), while red+sand combination in equal amounts was best for P. tithymaloides (Rani and Kumar, 1992, 1994a). A mixture of gravel + sand favoured maximum increase in plant height, fresh weight and dry weight in E. lathyris (Garg and Kumar, 1990; Kumar and Garg, 1995). Environmental factors influenced the growth and yield of Calotropis procera (Rani et al, 1990). Growth Curve Maximum growth was observed during June-July to October-November and also from February-March to May-June. Increase in hexane extractable was recorded upto 6-7 months; thereafter percent hexane extractable (HE) did not increase significantly in E. lathyris, E. antisyphilitica and P. tithymaoildes. Higher levels of HE were recorded in leaves as compared to the stem in E. lathyris, E. antisyphilitica and P. tithymaoildes. Higher levels of HE were recorded in leaves as compared to the stem in E. lathyris and in fruits of Calotropis procera. Active phase of growth exhibited gretaer amounts of hexane extractable. Fertilizer application Application of NPK singly of in various combinations improved growth of all the selected plants. In general NP combination gave better growth which was only slightly improved by the addition of K for E. tirucalli (Kumar and Kumar, 1983, 1986). When best doses of NPK were applied in different combinations like NP, NK, KP) and NPK, the last combination gave best results in the form of biomass, latex yield, sugars and chlorophyll in E. lathyris (Garg and Kumar, 1990) and P. tithymalides (Rani and Kumar, 1994a). In E. antisyphilitica however, NP combination gave best results, followed by NPK, for biomass production. Chlorophyll, sugars and latex yield was best in KP combination (Johari et al., a, 1990; Johari and Kumar, 1994a). Addition of FYM alone and with combination of urea improved FMY+Urea applications improved the productivity in comparison with FMY increased the plant height, fresh weight and dry weight to varying degrees. Hexane and methanol extractable also increased (Garg and Kumar ,1986, 1987b). Influence of Salinity Salinity stress studies were also made of on Euphoriba tirucalli (Kumar and Kumar 1986). Salinity was applied in the form of irrigation water. Lower concentrations of salinity improved plant growth of E. antisyphilitica (Johari et al, 1990, 1994b). But higher concentrations inhibited further increase in growth. Sugars however did not increase in any saline irrigation. A slightly higher level of salinity impaired chlorophyll synthesis also. At higher level of salinity, leaves of E. antisyphilitica became yellow and fell off but stem did not show any visible adverse effects. E. lathyris could also tolerate lower salinity levels, but its tolerance was higher than E. antisyphilitica. In E. lathyris salinity adversely affected the root growth (Garg and Kumar, 1989a, 1990). P. tiothymaloides also exhibited increases in biomass and yield at lower salinity levels and higher concentrations adversely affected the plants. Its underground part could tolerate slightly higher salinity concentration (Rani et al., 1991). Effect of growth regulators Spray of growth regulators resulted in enhanced fresh and dry weight production (Johari et al, 1991). However biocrude synthesis occurred more in auxins, NAA and IAA in E. antisyphilitica. Out of all the growth regulators employed on P. tithymaloides IAA supported maximum plant growth in terms of fresh weight and dry weight of aboveground and undergound plant parts. 2,4,5-T showed minimum plant growth, besides, certaion nodular structures were observed on the sterm of the plants treated with 2,4,5-T. Biocrude yield was best in IAA followed by 2,4,5-T, GA3, CCC, NAA and control. Application of growth regulators on P. tithymaloides resulted in slight decrease in chlorophyll over the control plants. Whereas on E. lathyris they induced favourable results, regarding chlorphyll (Garg and Kumar, 1987a). In E. lathyris IBA caused maximum fresh weight productivity followed by IAA, GA3 and NAA. NAA sprayed plants exhibited more production of hexane extractable. Favourable influence of growth regulators was also observed in sugar yield, maximum being in NAA followed by IBA, GA3 and IAA (Garg and Kumar 1987b) Disease affecting hydrocarbon yielding plants The cultivation of these plants suffers from plant pathogenic diseases affecting at root level. Investigations of pathogenicity and control aspects of charcoal root of E. lathyris (Garg and Kumar, 1987c); E. antisyphilitica (Johari and Kumar 1993) were carried out. Tissue culture techniques Plant tissue culture has been successfully employed to achieve rapid clonal propagation of E. lathyris (Kumar and Joshi, 1982), Pedilanthus tithymaloides (Rani and Kumar, 1994b), Eucalyfotus camaldulendis (Bhargava and Kumar, 1984) and E. antisyphilitica (Johari and Kumar 1994c). Likewise propagation of jojoba has also been carried out (Roy, 1992a). Jatropha curcas Linn is potential diesel fuel oil yielding plant and details about this are given in Roy and Kumar (1988) and Roy (2000 this volume) Bio-diesel production First efforts to cultivate hydrocarbon producing plants for fuel production were made by Italians in Ethiopia and French in Morocco. Later on Calvin and his collaborators have revived the idea again and have advocated the study of petro-crops as a possible feedstock for petroleum like materials. Presently the largest fuel programme is in Brazil where government currently spends a considerable amount on subsidizing the production of alcohol, mostly from biomass of sugarcane. Production was estimated to increase so muich that around 11 to 14 million cars will use alcohol (with gasoline) by the year 2000 (Korbitz, 1996). Recently about 30 thousand tones of rape biofuel yearly is produced at the industrial chemical factories in Poland (Grazybek et al., 1996). The important source investigated during last years from 1993 to 1996 included. Solid bioenergy carriers : whole cereals plants, wood from short rotation cultivation grasses with high biomass yield. Liquid bioenergy carriers : rapeseed oil, rape mathyl ester, bioethanol from potatoes, sugar beet and wheat. Agricultural/forestry residues : straw, wood residues, cut grasses from landscape cultivation. Liquid bioenergy carriers (RME) : rapeseed (oil fatty acid mathylester) is obtained from rapeseed. The advantage of liquid energy sources are best utilized as fuel for motor vehicles. RME can be used in conventional diesel engines in cars as substitute for diesel fuel (Kaltschmitt et al, 1996). Salt tolerance of hydrocarbon yielding plants Some of the hydrocarbon yielding plants have salinity tolerance of certaion hydrocarbon, e.g. rubber and oil yielding plants like jojoba (Simmondsia chinensis) (Yermanos et al., 1967), Parthenium argentatum (Pfeiffer and Bloss, 1989), Euphorbia lathyris, E. tirucalli (Kumar and Kumar 1986). Potential use of hydrocarbon yielding plants in obtaining biofuel was introduced by Nielson et al (1977). The hydrocarbons from Euphorbia areprimarily blend of C15, C20 and C30 compounds. When subjected to catalytic cracking biocrude yields various products virtually identified to those obtained by cracking naphtha a high quality petroleum fraction that is one of the principal raw material used in the chemical industries (Calvin, 1984). Latex rich in hydrocarbons is abundantly found in plants belonging to families Euphorbiaceae, Asclepiadaceae, Apocynaceae, Urticaceae, Convolvulaceae and Sapotaceae. Calvin (1984) suggested that exploration of hydrocarbon yielding plants gives rise to two practical approaches. Firstly to use hydrocarbons as it comes from the plants itself as crude oil refine it, remove the sterols which it contains, crack the rest of compounds to ethylene, propylene, etc. and then reconstruct other chemicals from those products and secondly to learn how the molecular weight is controlled and to manipulate the plants to reconstruct material of the desired nature. Calvin (1984) made a study of cracking pattern of extracts from Euphorbia lathyris using Zeolite catalyst at the Mobil Corporation research laboratories. Other materials which have also been cracked by this group are rubber latex from Hevea brasiliensis corn oil, castor oil and jojoba oil. Studies at Indian Institute of Petroleum on hydrocracking of two samples of biocrude using a catalyst developed at IIP had obtained 81 percent showed that it can provide about 24% gasoline, 22% kerosene, 18% gas oil and 6.6% gases (Bhatia et al, 1983). During the last 15 years investigations have been carried out on the optimization of yield and production of hydrocarbons by such plants at the 50 ha Energy Plantation Demonstration Project Centre. Their yield could be increased three fold making their commercial cultivation feasible. Several other countries are producing and selling biodiesel on commercial basis. Already European countries mainly Italy, Germany and Austria are leading in biodiesel production nearing 500,000 tons in 1997 out of which 2,50,000 was produced in France (Statt, 1998). The production capacity of bio-diesel in Germany was fully utilized in 1997, the sold quantity amounting to roughly 100,000 t (Groenen, 1998). The technologies for producing bio-oil are evolving rapidly with improving process performance, larger yield and better quality products (Schindlbauer and Hodl, 1995). Although there is significant volume of biodiesel already produced in Europe there are remaining risks slowing down the further expansion to the target set by the European Commission to reach 5% market share in transportation fuels by the year 2000. These risks are insecurity in raw material supply and prices, doubts about adequate quality assurance and hesitance for a wwider acceptance by the Diesel engine manufactures, mission marketing strategies for targeting biodiesel differential advantages into specific market niches and last not least missing legal frame conditions similar to clean air act in USA. Hydrocarbon Yielding Plants and Biodiesel Production A large number of hydrocarbon yielding plants are able to grow under semi-arid and arid conditions and they also produce valuable hydrocarbons (upto 30 percent of dry matter) which could be converted into petroleum like substances and be used as fossil fuel substitute. A critical factor determining the economic feasibility of novel energy crops is the avoidance of competition with conventional food, feed and fiber crops. Laticiferous plant with their rich hydrocarbon contents offer such potential plant systems which due to their water conservation ability thrive on limited amount of water, produce sufficient biomass and are unpalatable to the cattlefolk due to their sticky latex. Degraded and denuded soils are no hindrance to their growth. Jatropha curcas Linn is potential diesel fuel oil yielding plant and details about this are given in Roy and Kumar (1988) and Roy (2000 this volume) Table 1 EU draft specification for vegetable oil methylester diesel fuel (biodiesel) Properties Unit Limit Analytical Method A. Fuel specific properties Density at 15ºC g/cm3 0.86-0.90 IS)3775 Kinematic viscocisty at 40ºC mm2/s 3.5-5.0 ISO 3104 Flash point ºC Min 100 ISO 2719 Cold fitter plugging point CFFP ºC Summer max Winter max <-15 0 DIN EN 116 Sulphur content %wt Max 0.01 ISD 8754/DIN EN 41 Distillation 5% vol evaporated at ºC To be indicated ASTM 1160/ISO3405 5% vol evaporated at ºC To be indicated Carbon residue Conradson (10% by vol residue on distillation at reduced pressure) %wt Max 0.30 ISO 10370 Cetane number Min 49 ISO 5165/DIN 51773 Ash content Max 0.01 EN 26245 Water content (Karl Fischer) mg/kg Max 500 ISO 6296/ASTM D 1744 Particular matter g/m3 Max 20 DIN 51419 Cooper corrosion (31/50ºC) corrosion rating Max 1 ISO 2160 Oxidation stability g/m3 Max 25 ASTM D 2274 B. Methyl Ester Specific Properties Acid value KOH/g mg Max 0.5 ISO 660 Methanol content %wt Max 0.3 Din 51413.1 Monglycerides %wt Max 0.8 GLC Diglycerides %wt GLC Triglycerides %wt GLC Bound glycerides %wt GLC Bound glycerides %wt Max 0.2 Calculate Free glycerine %wt Max 0.03 GLC Total %wt Max 0.25 Calculate Iodine number Max 0.25 DIN 53241/IP 84/81 Phosphorous content mg/kg Max 10 DFG C-VI4 European Commission (EU) has suggested alternative to conventional hydrocarbon fuels such as methanol, ethanol, compressed natural gas (CNG), hydrogen vegetable oils and estierfied oils. EU has presented a proposasl in the framework EU’s ALTENER programme for the promotion of alternative fuels. Within this programme the EU has the objective of securing a five percent market share of total motor fuel consumption for biofuels of which it is expected that biodiesel will form the major share. EU draft specifications for vegetable oil Methylester Diesel fuels (biodiesel fuel) are given in Table 1 (Anonymous, 1995). Some countries notably Austria and Italy have already produced their own specifications for vegetable oil methylester diesel fuel these are given in table 2 and table 3 (Anonymous, 1995). Biodiesel production units are in operation or under construction in Austria, Belgium, Germany, France and Italy. Table 2 Austrian specification for vegetable oil methylester diesel fuel Property Units Limits Test method Density @15 ºC kg/m3 0.86-0.90 Din 51 757 Flash point PM ºC Min 55 ONORM C1122/ISO2719 CFFP ºC max 0.8 ONORM EN 116 Kinematic viscority at 20 ºC Min2/S 6.5-9.0 ISO 3104/ISO 3105 Sulphur content %m max 0.02 ONORM C1134 Carbon residue %m max 0.1 DIN 51 551 Conradson (CCR) Cetane number Mm 418 ISO 5165 Neutralization value Mg/KOH/g.max 1 ONORM c 1146 Methanol content % in max 0.2 GLC Free glycerine %m max 0.03 GLC/enzymatic Total glycerine % m max 0.25 GLC/enzymatic Rapeseed methylester diesel fuels are already sold in Italy but can only be marketed outside retail outlets. A Government decree fixes a maximum of 125,000 tones per year to be exempted from gas oil excise tax chain claiming tax exemption. Producers have to show that at least 80 percent of the raw vegetable oil used derives from “set-aside” crops. Environmental Benefits of biodiesel production Diesel engine exhaust (DEE) is classified carcinogenic to experimental animals and as probably carcinogenic agent to human by International Agency for Research on Cancer (International Agency for Research on Cancer, 1989). The mutagenic and cytotoxic effects of particulate extracts of diesel engine exhaust (DEE) using rape seed oil mathylester (RME) and soybean oil methylester (SME) as fuels were directly compared to DEE from fossil diesel fuel (DF). The results indicate a higher mutagenic potency of DEE of DF compared to RME and SME (Sams, 1995). Genetic engineering and future prospects The successful cloning of a long chain acylreducatse gene, the prospects of cloning the acylligase gene from jojoba and the transfer to these two genes into rapeseed has opened up the possibility of transgenic rapeseed plants producing a “jojoba wax” oil. Jojoba wax has many uses as medium to high value source of lubricants and cosmetics. Table 3 Italian specification for vegetable oil methylester diesel fuel Property Units Limits Test method Appearance Visual Clear and bright Density @15 ºC kg/m3 0.86-0.90 ASTM D2198/ISO 3675 Flash point ºC max 0 ATM D 93 Kinematic viscosity at 40 ºC Kg/m3 mm3/S 3.5-5.0 ASTM D 189/ISO 3104 Distillation IBP max 300 95% V max 360 Sulphur content %m max 0.01 ATM D 1552/ISO 8754q Carbon residue % m max 0.5 ASTMD 189/ISO/10370 Conradson (CCR) Water content ppm 700 ASTM D 1744 Saponification number Mg/KOH/g min 170 NGD G 33 – 1976 Total acidity Mg/KOH/g.max 0.05 ASTM D 664 Methanol content %m max 0.2 GLC Methylester %m min 98 GLC Monoglycerides %m max 0.8 GLC Diglycerides %m max 0.2 GLC Triglycerides %m max 0.1 GLC Free glecerides % m max 0.05 GLC Phosphhorus ppm 10 DGF Gill 16A.89 The potential and value of genetic engineering as a means of obtaining oils with highly diversified chemical composition and targeted to the requirements of farmers, consumers and industry is clearly illustrated by success obtained in a crop such as rapeseed. 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