High-value oils from plants

The seed oils of domesticated oilseed crops are major agricultural commodities that are used primarily for nutritional applications, but in recent years there has been increasing use of these oils for production of biofuels and chemical feedstocks. This is being driven in part by the rapidly rising costs of petroleum, increased concern about the environmental impact of using fossil oil, and the need to develop renewable domestic sources of fuel and industrial raw materials. There is also a need to develop sustainable sources of nutritionally important fatty acids such as those that are typically derived from fish oil. Plant oils can provide renewable sources of high-value fatty acids for both the chemical and health-related industries. The value and application of an oil are determined largely by its fatty acid composition, and while most vegetable oils contain just five basic fatty acid structures, there is a rich diversity of fatty acids present in nature, many of which have potential usage in industry. In this review, we describe several areas where plant oils can have a significant impact on the emerging bioeconomy and the types of fatty acids that are required in these various applications. We also outline the current understanding of the underlying biochemical and molecular mechanisms of seed oil production, and the challenges and potential in translating this knowledge into the rational design and engineering of crop plants to produce high-value oils in plant seeds.     

Engineering plant oils as high-value industrial feedstocks for biorefining: the need for underpinning cell biology research

Plant oils represent renewable sources of long-chain hydrocarbons that can be used as both fuel and chemical feedstocks, and genetic engineering offers an opportunity to create further high-value specialty oils for specific industrial uses. While many genes have been identified for the production of industrially important fatty acids, expression of these genes in transgenic plants has routinely resulted in a low accumulation of the desired fatty acids, indicating that significantly more knowledge of seed oil production is required before any future rational engineering designs are attempted. Here, we provide an overview of the cellular features of fatty acid desaturases, the so-called diverged desaturases, and diacylglycerol acyltransferases, three sets of enzymes that play a central role in determining the types and amounts of fatty acids that are present in seed oil, and as such, the final application and value of the oil. Recent studies of the intracellular trafficking, assembly and regulation of these enzymes have provided new insights to the mechanisms of storage oil production, and suggest that the compartmentalization of enzyme activities within specific regions or subdomains of the ER may be essential for both the synthesis of novel fatty acid structures and the channeling of these important fatty acids into seed storage oils.     

Metabolic engineering of fatty acid biosynthesis in plants.

Fatty acids are the most abundant form of reduced carbon chains available from nature and have diverse uses ranging from food to industrial feedstocks. Plants represent a significant renewable source of fatty acids because many species accumulate them in the form of triacylglycerol as major storage components in seeds. With the advent of plant transformation technology, metabolic engineering of oilseed fatty acids has become possible and transgenic plant oils represent some of the first successes in design of modified plant products. Directed gene down-regulation strategies have enabled the specific tailoring of common fatty acids in several oilseed crops. In addition, transfer of novel fatty acid biosynthetic genes from noncommercial plants has allowed the production of novel oil compositions in oilseed crops. These and future endeavors aim to produce seeds higher in oil content as well as new oils that are more stable, are healthier for humans, and can serve as a renewable source of industrial commodities. Large-scale new industrial uses of engineered plant oils are on the horizon but will require a better understanding of factors that limit the accumulation of unusual fatty acid structures in seeds.     

Castor oil: a vital industrial raw material

Even though castor oil is inedible, it has long been an article of commerce. This is, in large measure, due to the versatility of the oil. This article discusses the extraction of castor oil and its refining methods and reviews the industrial applications of the oil. Since castor oil is not edible, it could be substituted in many industrial application areas where edible oils are used. An awareness of the various uses of the oil can be used to make a strong case for an increase in its production as a vital raw material for the chemical industries.     

Biodiesel from microalgae

Continued use of petroleum sourced fuels is now widely recognized as unsustainable because of depleting supplies and the contribution of these fuels to the accumulation of carbon dioxide in the environment. Renewable, carbon neutral, transport fuels are necessary for environmental and economic sustainability. Biodiesel derived from oil crops is a potential renewable and carbon neutral alternative to petroleum fuels. Unfortunately, biodiesel from oil crops, waste cooking oil and animal fat cannot realistically satisfy even a small fraction of the existing demand for transport fuels. As demonstrated here, microalgae appear to be the only source of renewable biodiesel that is capable of meeting the global demand for transport fuels. Like plants, microalgae use sunlight to produce oils but they do so more efficiently than crop plants. Oil productivity of many microalgae greatly exceeds the oil productivity of the best producing oil crops. Approaches for making microalgal biodiesel economically competitive with petrodiesel are discussed.     

车八岭国家级自然保护区油脂植物资源

油脂植物广泛存在于植物界,它们的果实、种子、花粉、孢子、茎、叶、根等器官都含有油脂,尤其以种子含油量最丰富.油脂植物是构成车八岭国家级自然保护区生物多样性重要组成部分,初步调查,车八岭国家级自然保护区共有油脂植物55科96属144种.车八岭保护区内野生油脂种类繁多,资源丰富,能适应多种需求,具有无法估计的生态和经济价值.目前对野生油脂植物开发利用较少,经营比较粗放,许多资源尚未得到利用,建议进一步开展油脂植物研究,查清油脂植物的分布特点、主要油脂植物的特点以及可开发利用性、资源蕴藏量,以便制定科学利用计划,引导当地群众合理利用区内的油脂植物资源,可增加农民收入,促进农村经济发展,减轻对林木资源的依赖.     

Fuel oils from euphorbs and other plants

Fuel oils from Euphorbs and other plants. The increasing energy costs of finding petroleum, together with the sure knowledge that its supply is finite, has prompted us to seek other sources of liquid hydrocarbon for both fuel and material. We have turned to annually renewable plant sources such as seed oils, an obvious source, with palm oil as the most productive. Sugar cane used to produce ethanol is another fuel source already in use.
We have examined non-food plants which can be grown on marginal soil for their productivity, particularly the genus Euphorbia. All species of this genus produce a latex which can be converted into useful fuel and other material, including precursors for what might be a valuable anti-tumor agent. Euphorbias and other similar plants require repeated planting and harvesting of the entire plant, which constitutes a drain on the soil. Trees can be long-term sources for hydrocarbon-like materials with a single planting. Examples are: the genus Copaifera which can be tapped for sesquiterpenes, the genus Pittosporum which bears fruits rich in terpenes and can be harvested annually. Finally, there are algae whose oil productivity is already of interest.
It seems possible to modify genetically the terpene biosynthetic pathways in plants to improve both the quality and quantity of the oils produced from them.     

Food, feed or medicine: The multiple functions of edible wild plants in Vietnam

Many of the edible wild plants that are included in local food baskets have both therapeutic and dietary functions. Such medicinal foods have been part of Eastern medicinal theories since ancient times and have recently received attention in the USA and Europe within the fields of functional foods, neutraceuticals and phyto-nutrients. This paper provides an example from Vietnam of the continued use of a multitude of edible wild vegetables. Vietnamese traditional medicine also holds an important position within the health care system and many of the plants that are used have both dietary and medicinal functions. Using a combination of qualitative and quantitative techniques (Rapid Rural Appraisal and Food Frequency Questionnaires), information on over 90 species of edible wild plants was obtained from 4 villages in the Mekong Delta and the Central Highlands. About a third of the plants also had therapeutic roles, forty percent were used also as livestock feeds and one fifth were used as food/livestock feed/ medicine. From a nutrition viewpoint it is important to pay attention to this group of traditional foods for several reasons. Their direct nutritional contribution is often significant but neglected. Very little is known about the health benefits of regular consumption of small quantities of medicinal foods and an important “medicinal role” of traditional plant medicines may be the contribution of small quantities of trace minerals and vitamins. The parallel functions as livestock feeds make animal products more accessible to poor households and help improve the quality of their diets.     

Bioplastik aus Nutzpflanzen: Palette der nachwachsenden Rohstoffe erweitert

Crop plants are ultivated for producing starch, oils, proteins, sugar, fibres and other products. An increasing amount of these products is used as renewable resources for industrial purposes. But there is still a demand for new products with improved properties such as biodegradable plastics like polyhydroxyfatty acids (PHF) which cannot be found in the plant kingdom. PHF are linear polymers found as a major storage component in many bacterial species. Polyhydroxy‐butyric acid, poly(3HB), is the most abundant representative of this class of polymers. Three enzymes have been identified from the bacterium Ralstonia eutropha responsible for poly(3HB)‐synthesis. These enzymes are encoded by three different genes. PHF can be utilized by many microorganisms as carbon‐ and energy‐source with the help of certain depo lymerases. PHF‐storing plants fulfill the criteria as renewable resource for biodegradable plastics. Using Arabidopsis thaliana as a model plant, the poly(3HB)‐metabolism has been established in plants after transformation with the three bacterial genes under the control of plant promotors. Transgenic plants have been selected accumulating up to 40% poly(3HB) dry weight. Recent data demonstrate that high amounts of poly(3HB) can also be stored in rape seed, the main oil producing rop for moderate limates. This offers the possibility to breed poly(3HB)‐producing rop plants with full agronomical performance.     

Transgenic oil palm: production and projection

Oil palm is an important economic crop for Malaysia. Genetic engineering could be applied to produce transgenic oil palms with high value-added fatty acids and novel products to ensure the sustainability of the palm oil industry. Establishment of a reliable transformation and regeneration system is essential for genetic engineering. Biolistic was initially chosen as the method for oil palm transformation as it has been the most successful method for monocotyledons to date. Optimization of physical and biological parameters, including testing of promoters and selective agents, was carried out as a prerequisite for stable transformation. This has resulted in the successful transfer of reporter genes into oil palm and the regeneration of transgenic oil palm, thus making it possible to improve the oil palm through genetic engineering. Besides application of the Biolistics method, studies on transformation mediated by Agrobacterium and utilization of the green fluorescent protein gene as a selectable marker gene have been initiated. Upon the development of a reliable transformation system, a number of useful targets are being projected for oil palm improvement. Among these targets are high-oleate and high-stearate oils, and the production of industrial feedstock such as biodegradable plastics. The efforts in oil palm genetic engineering are thus not targeted as commodity palm oil. Due to the long life cycle of the palm and the time taken to regenerate plants in tissue culture, it is envisaged that commercial planting of transgenic palms will not occur any earlier than the year 2020.     

滇南8种珍贵香科植物的开发利用

在云南热区发掘和初步引种栽培结果的8种野生香料植物,为珍贵资源。从它们的利用部位花、果、叶和根中,可提取芳香油,主要成分分别为芳樟醇、香叶醇、金合欢醇、黄樟素、柠檬醛、茴香醚及癸醛、十二碳醛等,含量相当高,为重要调香原料,有的作药用,颇具发展种植和开发利用价值。     

石油污染对鸟类的影响及石油污染清洁修复技术的研究进展

石油污染物通过自然泄漏和各种人类活动进入生态环境,对鸟类的生存产生影响。本文综述了国内外有关石油污染物对鸟类所产生的影响、受污染鸟类及其栖息地的清洁修复技术的研究现状以及发展趋势。现有研究发现,石油的毒性和石油对羽毛结构与功能的破坏是石油污染影响鸟类的主要原因。石油污染不仅对鸟类有直接的致死作用,而且能产生许多慢性危害,包括引起鸟类溶血性贫血、使其免疫能力下降、降低羽毛的保温和防水能力等。对鸟类栖息地中的石油污染进行及时清理并开展对受污染鸟类的清洁修复工作,是减轻石油污染对鸟类影响的重要手段。我国作为石油消费大国,关于石油污染对鸟类影响的研究与国外相比滞后,亟需在石油污染对鸟类的短期和长期影响、受污染鸟类及其栖息地的清洁修复技术等方面开展更多的研究。     

The Oil Bodies of Liverworts: Unique and Important Organelles in Land Plants

Oil bodies of liverworts are intracellular organelles bounded by a single unit membrane containing lipophilic globules suspended in a proteinaceous matrix. They are a prominent and highly distinctive organelle uniquely found in liverworts. Although they have been widely used in taxonomy and chemosystematics, and many of their secondary metabolites are known to be bioactive and are considered as potential sources of medicines, their origin, development and function still remain poorly understood. Recently, biochemical studies have indicated that the isoprenoid biosynthetic pathways in liverworts are similar to those of the seed plants and that oil bodies of Marchantia polymorpha contain a protein complex immunologically related to plastid and cytosolic enzymes of isoprenoid synthesis. Cytoplasmic lipid droplets lacking a bounding membrane have recently been recognized as important dynamic organelles playing active roles in cell physiology. Structural proteins, covering the surface of the lipid droplets and preventing them coalescing during desiccation, have been found in seed plants and also in the moss Physcomitrella patens. However, whether liverwort oil bodies play a dynamic role in cell metabolism, in addition to their role as sites of essential oil accumulation and sequestration, has not been formally tested. In this review, we present current knowledge on the oil bodies of liverworts on their origin and development, their role in taxonomy, chemosystematics and potential pharmaceutical applications leading to their functional significance, and we also identify avenues for future studies on this important but long-overlooked organelle.     

Biodiesel production from Jatropha oil by catalytic and non-catalytic approaches: an overview

Biodiesel (fatty acids alkyl esters) is a promising alternative fuel to replace petroleum-based diesel that is obtained from renewable sources such as vegetable oil, animal fat and waste cooking oil. Vegetable oils are more suitable source for biodiesel production compared to animal fats and waste cooking since they are renewable in nature. However, there is a concern that biodiesel production from vegetable oil would disturb the food market. Oil from Jatropha curcas is an acceptable choice for biodiesel production because it is non-edible and can be easily grown in a harsh environment. Moreover, alkyl esters of jatropha oil meet the standard of biodiesel in many countries. Thus, the present paper provides a review on the transesterification methods for biodiesel production using jatropha oil as feedstock.     

Growth and polyhydroxybutyrate production by Ralstonia eutropha in emulsified plant oil medium

Polyhydroxyalkanoates (PHAs) are natural polyesters synthesized by bacteria for carbon and energy storage that also have commercial potential as bioplastics. One promising class of carbon feedstocks for industrial PHA production is plant oils, due to the high carbon content of these compounds. The bacterium Ralstonia eutropha accumulates high levels of PHA and can effectively utilize plant oil. Growth experiments that include plant oil, however, are difficult to conduct in a quantitative and reproducible manner due to the heterogeneity of the two-phase medium. In order to overcome this obstacle, a new culture method was developed in which palm oil was emulsified in growth medium using the glycoprotein gum arabic as the emulsifying agent. Gum arabic did not influence R. eutropha growth and could not be used as a nutrient source by the bacteria. R. eutropha was grown in the emulsified oil medium and PHA production was measured over time. Additionally, an extraction method was developed to monitor oil consumption. The new method described in this study allows quantitative, reproducible R. eutropha experiments to be performed with plant oils. The method may also prove useful for studying growth of different bacteria on plant oils and other hydrophobic carbon sources.     

Chemical composition and antifeedant activity of some aromatic plants against pine weevil (Hylobius abietis)

The pine weevil Hylobius abietis is an important pest causing severe damage to conifer seedlings in reforestation areas in Europe and Asia. Plants that have no evolutionary history with the pine weevil are of special interest in the search for compounds with a strong antifeedant activity. Thus, the essential oils of nine aromatic plants, viz Amomum subulatum, Cinnamomum tamala, Curcuma longa, Laurus nobilis, Ocimum basilicum, Origanum majorana, Origanum vulgare, Syzygium aromaticum and Trachyspermum ammi were extracted by hydrodistillation. The essential oil constituents were identified by gas chromatography–mass spectrometry, and antifeedant properties towards the pine weevil were assessed using choice feeding bioassay. The essential oils of C. longa, O. majorana, S. aromaticum and T. ammi showed an excellent antifeedant activity towards the pine weevil for 24 hr, whereas the essential oil of other plants showed the activity for 6 hr. There was a positive correlation between the amount of benzenoid compounds and the antifeedant activity of the essential oils. This study suggests that pine weevil non-host plant compounds have potential to be used for the protection of seedlings against pine weevil feeding. However, further study will be needed to explore the antifeedant activity of individual components and oils in the laboratory as well as in the field.     

Metabolic engineering of edible plant oils]

Plant seed oil is the major source of many fatty acids for human nutrition, and also one of industrial feedstocks. Recent advances in understanding of the basic biochemistry of seed oil biosynthesis, coupled with cloning of the genes encoding the enzymes involved in fatty acid modification and oil accumulation, have set the stage for the metabolic engineering of oilseed crops that produce "designer" plant seed oils with the improved nutritional values for human being. In this review we provide an overview of seed oil biosynthesis/regulation and highlight the key enzymatic steps that are targets for gene manipulation. The strategies of metabolic engineering of fatty acids in oilseeds, including overexpression or suppression of genes encoding single or multi-step biosynthetic pathways and assembling the complete pathway for the synthesis of long-chain polyunsaturated fatty acids (e.g. arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid) are described in detail. The current "bottlenecks" in using common oilseeds as "bioreactors" for commercial production of high-value fatty acids are analyzed. It is also discussed that the future research focuses of oilseed metabolic engineering and the prospects in creating renewable sources and promoting the sustainable development of human society and economy.     

Compartmentation of triacylglycerol accumulation in plants

Triacylglycerols from plants, familiar to most people as vegetable oils, supply 25% of dietary calories to the developed world and are increasingly a source for renewable biomaterials and fuels. Demand for vegetable oils will double by 2030, which can be met only by increased oil production. Triacylglycerol synthesis is accomplished through the coordinate action of multiple pathways in multiple subcellular compartments. Recent information has revealed an underappreciated complexity in pathways for synthesis and accumulation of this important energy-rich class of molecules.