生物转化脂肪酸合成ω-羟基酸和ω-氨基酸研究进展

ω-羟基脂肪酸和ω-氨基脂肪酸可广泛用于聚酯、聚酰胺等高分子的合成以及润滑油、生物燃料、医药中间体等化工产品的生产。近年来，以自然界丰富的可再生资源脂肪酸为绿色原料，生产这类可降解的生物基材料及化学品引起了人们的广泛兴趣，其中从植物油中的油酸、亚油酸等脂肪酸出发生产中链脂肪酸及其羟基、氨基衍生物的非天然生物催化反应也越来越丰富，是合成生物学技术在油脂资源转化方面的一个重要应用。综述了近年来中链ω-羟基脂肪酸与ω-氨基脂肪酸生物合成的研究进展，展示了通过多酶级联催化反应将可再生的脂肪酸生物转化，可持续生产9-羟基壬酸、6-氨基己酸、ω-氨基十二烷酸等高附加值精细化学品的合成路径和应用前景。     

Fettchemische und petrochemische Rohstoffe - Gegensatz oder Ergänzung?

Fatchemical and Petrochemical Raw Materials - Contrast or Complementation? Fatchemical products are used in all branches of industry and crafts for a variety of purposes. The areas of application are determined by the types of fatty acids which are available as raw materials. It is shown that the C₁₈ chain length is dominant. The most commonly occurring fatty acids are oleic- and linoleic acids. Lauric acids, which is so important for the major areas of application, only represents a small fraction of the world supply of fats. The use of raw material alternatives instead of fats is explained by the relative uniformity of the fatty acid spectrum found amongst the natural fatty acids. In addition, the special place occupied by coconut oil is economically attractive. A survey of the various possibilities and processes for fatchemical products which are derived from fats and petrochemical derivatives is presented. It may be expected that further positive developments of agricultural oil. and fat-production will occur by better yields as well as by successful breeding, resulting in changes in the fat composition. In the long term it may be assumed that the range of natural fats will not only expand, but that it will also be widened by new fatty acid compositions. Petrochemical processes can also have good prospects for the future. Fatchemical and petrochemical raw materials can complement each other in a positive fashion thus enriching the spectrum of fatchemical products.     

Challenges to a mature industry: Marketing and economics of oleochemicals in Western Europe

Basic oleochemicals are produced by splitting and further reactions of oils and fats: fatty acids, glycerine, fatty acid methyl esters, fatty alcohols and amines. The last two are included in the list of oleochemical raw materials, primarily because of their importance in the preparations of further derivatives. The wide range of derivatives of oleochemical raw materials such as fatty alcohol ethoxylates, fatty alcohol sulfates, fatty alcohol ether sulfates, quaternary ammonium compounds and soaps are summarized. Oleochemicals such as fatty alcohols and glycerine from oils and fats have equivalents on the basis of petrochemicals. Using the customary terminology, petrochemical products are referred to as “synthetics.” The are included in the present discussion because in the application of oleochemical raw materials the origin of the material is often less important than the structure. Oleochemistry can be regarded as a mature branch of chemistry, with many applications for its products, but with few completely new fields. The challenge and the opportunities for oleochemistry today lie in the changing economic and ecological conditions. Availability and price development of oils and fats are discussed with particular reference to European conditions, for these are the prerequisites if oleochemicals are to be competitive and are to improve their chances in the marketplace. The importance and development of the oleochemical raw material fatty acids, fatty acid methyl esters, glycerine, fatty alcohols and amines are considered on the basis of historical data. In considering future developments of oleochemicals, the capacity, demand and the possible influence of petrochemistry or crude oil is discussed. The highly developed oleochemical raw materials industry is a flexible supplier of medium-to long-chain fatty alkyl groups. These facts, together with the well organized supply lines for raw materials and the considerable potential of these renewable raw materials, could provide the necessary conditions for the oleochemical raw materials industry to fulfil its future tasks on a larger scale. This could arise, for example, due to the partial substitution of petrochemical surfactants, if this should become necessary as a result of developments in the price and availability of crude oil, or on grounds of ecological factors.     

Challenges to a mature industry: Marketing and economics of oleochemicals in the United States

Fatty acids, accounting for more than half of oleochemicals discussed, grew at an annual rate of ca. 3% during the 1970s, with no growth since 1979. As competition intensified, the number of companies in the industry declined or owenrship changed. Challenges are covered under five major headings—markets, raw materials, competition, research and profitability. Oleochemical markets are extremely diverse but usually involve surface modification. Fatty acid disposition and real consumer personal income correlate closely. Growth of consumer income in the 1980s will be the most important factor in determining growth of fatty chemicals. Fatty chemicals compete with petroleum-derived products; and, therefore, price relationship of natural fats versus petroleum will affect market share. Tallow and other natural fats and oils are approximately the same price as 15 years ago, whereas ethylene has about doubled. Interchangeability of natural fats tends to moderate price fluctuations. Competition remains intense with market shares divided among many companies. Neither imports nor exports have played a significant role in the US fatty chemical industry. There are large exports of fatty acid derivatives, particularly to South America. Research will concentrate on energy reduction as oleochemical production is highly energy-intensive. Enzymatic splitting is a potential commercial process for this purpose. Improved hydrogenation catalysts and development of new specialty oilseeds are additional research objectives. Success of researchers will probably play the biggest role of all in future marketing and economics of fatty chemical companies. The belief is that the fatty chemical industry has had difficulty in consistently maintaining acceptable levels of profitability. To avoid extinction and achieve reasonable rates of return, business strategies must (a) identify, create and exploit growth segments; (b) emphasize product quality and innovative product improvement; and (c) systematically improve production and distribution efficiencies.     

Panel discussion and symposium: Nonfood uses of coconut oil: Where are we headed?

Coconut oil prices will exert much influence on synthetic fatty acid commercialization; if domestic oil prices maintain at 12–13￠/lb, demand for coco acids and derivatives could triple during the next three years; however, at an oil price of 22–24￠/lb, about 90% of domestic research and development on lauric acid products would be dropped. Synthetic fatty acids could hold the market if they can be commercialized near present prices. Proportionally higher food uses will be evident for coconut oil for the next several years. Increased demand for short chain (C₅–C₉) acids in high temperature synthetic lubricants, estimated to grow from the present 25 million lb/year to 50 million lb/year by 1973, will exert an increased demand. Conducted at the AOCS Meeting, San Francisco, April 1969.     

New natural antioxidants for protecting omega‐3 rich products

The long‐chain (LC) highly unsaturated omega‐3 fatty acids, EPA (eicosapentaenoic acid, 20:5) and DHA (docosahexaenoic acid, 22:6) are vital for a wide range of biological functions and are implicated in the prevention of numerous diseases. However, these fatty acids are highly susceptible to oxidation because of their unsaturated nature. Addition of antioxidants is one method to prevent lipid oxidation. As synthetic antioxidants may have carcinogenic effects at higher levels, the replacement of synthetic antioxidants with natural antioxidants is now in demand. We have isolated natural antioxidants from yoghurt, potato peel, fish protein hydrolysates and seaweed, which were able to protect highly unsaturated fish oil from oxidation. These antioxidant extracts may have potential for commercial exploitation.     

Antimicrobial lipids: Natural and synthetic fatty acids and monoglycerides

Over 40 natural or synthetic lipophilic compounds were screened for antimicrobial activity. Gram (+) bacteria and yeasts but not Gram (−) bacteria were affected by these agents. Epimino and selena fatty acids are more active than their corresponding straight chain unsubstituted fatty acids. The position of selenium influenced the antimicrobial activity of the fatty acid. The presence and position of a double or triple bond, usually an important factor in long chain fatty acids (>C₁₄) had little or no effect in C₁₁ fatty acids. Optimum antimicrobial activity was found for fatty acids and their corresponding monoglycerides when the chain length was C₁₂. The dilaurin derivative was not active.     

New developments in synthetic fatty acids

New developments in synthetic fatty acids have occurred in the last few years in Russia, Japan, the United States and Canada. In 1959 Russia decided to replace 40% of natural fatty acids in soaps with synthetic fatty acids. In 1966, 548 million pounds of C₅–C₃₀ synthetic fatty acids were produced including 288 million pounds of C₁₀–C₂₀ fatty acids. Forty million pounds of fatty acids are converted directly to the fatty alcohols for detergent use. A conservative estimate predicts that one billion pounds of synthetic fatty acids will be produced in Russia by the end of the current five-year program. Reports say that the Japanese have been interested in the oxidation of not only paraffin hydrocarbons but naphthenic petroleum hydrocarbons as well. Production of lower homology fatty acids up to butyric acid is being seriously considered in Japan. In America the most likely syntheses aside from “oxo” syntheses being considered for the manufacture of products like lauric acid is the carboxylation of the Ziegler intermediates prepared from ethylene polymerization. Some data on the current and future coconut oil consumption by major end-use for Canada and the United States are presented. Synthetic lauric acid is predicted for 1970 in the United States. Prepared from an address given at a meeting of the Northeast Section, New York, June 1968.     

Lipid modification of amino acids,carbohydrates and polyols

Agricultural crops provide a considerable reservoir of useful and low cost raw materials like fats and oils, plant proteins and carbohydrates. By selective combination of their molecular constituents (e. g. fatty acids, glycerol, amino acids, saccharides), a wide variety of surface active materials can be prepared. Due to their molecular constitution, all of them are potentially biodegradable. In this article we describe two generally applicable methods for the synthesis of such combination products using fatty acids from plant oils – one of the most important renewable materials as feedstock for the chemical industry – in combination with amino acids and monosaccharides including sugar alcohols. Using the high selectivities displayed by lipases, which catalyze a wide variety of transformations under very mild conditions (pH, temperature) with high atom efficiency in various non‐toxic solvents and without the production of by‐products or waste, numerous useful products can be obtained ranging all the way from surface active compounds (detergents and emulsifiers for food and personal care products) such as mono‐ and diglycerides, sugar esters, synthetic building blocks, products for food and dietary applications, all the way to novel methods for the production of biofuels (biodiesel). In our continuing effort to devise novel and generally applicable methods for the syntheses of such combination products we recently discovered a novel class of building blocks, fatty acid modified anhydrides of hydroxy carboxylic acids such as citric acid, tartaric acid and malic acid which led to alternative synthetic approaches towards new classes of the title compounds.     

Zusammensetzung und Anwendungen von Isostearinsäure

Composition and Application of Isostearic Acid The clay catalysed oligomerisation of unsaturated fatty acids yields C36 dimer fatty acids, C54 trimer fatty acids and C18 monomer fatty acids. Monomer fatty acids, which consists mainly of straight, branched, saturated and unsaturated fatty acids, can be distilled from the higher molecular weight products and after hydrogenation separated into solid stearic acid are mono- and polybranched C18 fatty acids whose branching points are mainly concentrated in the center of the molecule. Depending on the nature of the used raw materials and the degree of refinery, straight chain fatty acids, cyclic fatty acids, γ-lactones, unsaponifiable and even rosin acids are found as impurities. The low cloudpoint, comparable with oleic acid, as well as the excellent temperature- and oxidation stability gives isostearic acid and their derivatives excellent opportunities in applications as cosmetics, lubricants and plastics.     

Mitochondrial metabolism of (D,L)-threo-9, 10-dibromo palmitic acid

Bromination of palmitoleic or palmitelaidic acid proceeds bytrans addition and yields dibrominated products which cannot undergo β-oxidation when incubated with mitochondria isolated from hamster brown adipose tissue. These mitochondria were selected because they have a high capacity for oxidation of C₁₆ fatty acids and because they are readily uncoupled by an excess of free fatty acids of this chain length. The only metabolites which could be recovered from the incubation mixtures were dibromopalmitoylcarnitine and dibromopalmitoyl CoA. Free fatty acid was also recovered. Addition of synthetic carnitine or CoA esters of brominated fatty acids did not interfere with subsequent oxidation of palmitoylcarnitine. Addition of the free brominated fatty acids did significantly increase the rate of oxidation of subsequent additions of palmitoylcarnitine, as did other known synthetic uncouplers. These results are consistent with observations by others that feeding brominated oils leads to brominated fatty acid incorporation into tissue lipids, and indicate why this is so. They also provide a possible explanation for the hepatic damage noted in feeding experiments.     

Functionality at the end of a fatty acid chain – chemical and biological routes to ω‐hydroxylated fatty acids

Hydroxylated fatty acids are valuable compounds in the chemical industry, being used in various products. ω‐Hydroxylated fatty acids are versatile oleochemicals that can be used in polyester and polyamide production. Although a significant number of conventional synthetic chemistry production routes have been developed for ω‐hydroxy acids, considerable challenge relates to their production in price‐competitive, renewable, and sustainable production systems. The development and utilisation of biological systems for ω‐hydroxy acid production may allow the transition of these compounds from specialty chemical to commodity material. The viability of biological routes to ω‐hydroxylated fatty acids is dependent on the identification of enzymes and systems capable of such modifications. Cytochrome P450 monooxygenases are currently the only characterised enzymes known to ω‐hydroxylate fatty acids and yeast provides valuable systems to perform the ω‐hydroxylation biotransformations.     

Trends in industrial uses of palm and lauric oils

An attempt is being made to determine the importance of palm and lauric oil today and in the coming years of this decade whereby their industrial use in western Europe is considered outside the field of human and animal nutrition. The basic oleochemicals like fatty acids, fatty acid methyl esters, fatty alcohols and their most important derivatives are discussed as the essential products. Detergents are one of the most significant areas of application for basic oleochemicals and their derivatives. Changes in the application profiles of the final products are expected for the detergent industry in the coming years. These tendencies have been scrutinized with respect to their influence on future demand for palm and lauric oil. The competitiveness of natural oil-based oleochemicals versus ethylene-and paraffin-based synthetics is of great significance for the development of natural oils. It is attempted to elucidate the chances of natural oleochemicals in connection with petrochemical raw material developments.     

Synthesis and Anti-Listeria Properties of Odorless Hybrid Bio-Based n-Phenolic Vegetable Branched-Chain Fatty Acids

Consumers are becoming concerned about the impact of synthetic chemicals on human health and environments, and demanding natural compounds to reduce risk of antibiotic resistance of microorganisms. However, natural compounds are often less effective than synthetic antimicrobials. This challenge may be addressed with the development of bio-based antimicrobial agents. In this study, bio-based n-phenolic branched-chain fatty acids (n-phenolic-branched chain fatty acid [BCFA]) were synthesized from vegetable oil (soybean and safflower) fatty acids and four natural phenolics (phenol, thymol, carvacrol, and creosote), and tested against Listeria innocua. Results revealed that the newly synthesized products in crude form had minimum inhibitory concentrations (MIC) against L. innocua ranging from 3.6 to 116.4 μg mL⁻¹, with phenol-BCFA products having the lowest MIC (3.6 μg mL⁻¹) and minimum bactericidal concentration (MBC) (7.3 μg mL⁻¹). The precursors (unsaturated free fatty acids and phenolics) and noncovalently bound mixture of free fatty acids and phenolics had MIC above 232.7 μg mL⁻¹. After purification by molecular fractionation, n-phenolic-BCFA in the free fatty acid/monomer form were shown to be responsible for the anti-Listeria activity with MIC of 3.6–7.3 μg mL⁻¹ and MBC of 7.3–29.1 μg mL⁻¹. These promising results pave the road for further study of this new class of bio-based compounds, which may lead to their widespread use.     

Total Synthesis and Structural Elucidation of Two Unusual Non-Methylene-Interrupted Fatty Acids in Ovaries of the Limpet <Emphasis Type="Italic">Cellana toreuma</Emphasis>

In our previous study, unusual odd‐numbered dienoic acids with a terminal olefin were found as minor components in ovaries of the Japanese limpet Cellana toreuma, and the synthetic interests have been focused onto their structural confirmation and the inspection into their potential biological activity. Here, we describe an efficient and stereoselective total synthesis of two new unusual dienoic acids, 19:2?7,18 and 21:2?7,20, through a common pathway involving the strategic combination of alkyne‐zipper reaction and Lindlar hydrogenation for the construction of their unique carbon chains. In our synthetic study, 2‐propyn‐1‐ol was at first subjected to alkylation and alkyne‐zipper reaction to form the two fragments, and the subsequent carbon chain elongation was achieved by the usual coupling reaction to obtain the C‐19 and C‐21 products bearing an internal acetylenic group. Then, the internal acetylenic group of these products was subjected to Lindlar hydrogenation to form a Z‐alkenyl moiety, and the subsequent deprotection of the products was carried out under an acidic condition without isomerization of the internal Z‐alkenyl group. Total synthesis of target fatty acids, 19:2?7,18 and 21:2?7,20, was finally accomplished by two‐step oxidation of the resulting alcohols into carboxylic acids in a highly chemoselective manner, and the structures of these unusual natural fatty acids were finally elucidated by identifying the GC–MS spectra of the methyl esters of authentic and synthetic fatty acids.     

Effect of resin components on the degradation of guayule rubber

All natural rubbers are likely to contain some long chain fatty acids or their esters. The individual effect of the four C₁₈ fatty acids (stearic, oleic, linoleic, and linolenic acid) present in the guayule resin on the degradation of guayule rubber has been investigated concurrently by stress–relaxation of radiation cured rubber networks and by gel permeation chromatography studies on the raw rubber in the temperature zone 70–125°C. C₁₈ unsaturated fatty acids enhance the degradation of rubber several fold. The rate of degradation follows the order: rubber ≤ rubber + stearic acid < rubber + oleic acid < rubber + linoleic acid < rubber + linolenic acid. The thermal degradation is slower than the thermooxidative. The rate of degradation monotonically increased with the number of conjugated double bonds and is first order with respect to acid concentration. The activation energy for the chain scission for both thermal and thermooxidative degradation has been found to be 95 ± 10 kJ/mol. The mechanism of degradation of guayule rubber in the presence of fatty acids is discussed.     

Processing for industrial fatty acids - I

Palm kernel and coconut oils are particularly important to the fatty acid industry because they are the major sources of lauric acid. This paper describes the processes used to convert these oils to their fatty acids. These in turn may be fractionated into saturated/unsaturated acids and to specific chain lengths by winterization, panning and pressing, fractional distillation, solvent crystallization and hydrophilization methods. The products are important raw materials for the soap, detergent and oleochemical industries. Emery Industries     

Heat Treatment and Chemical Composition of Fatty Acids and Rosin Acids Mixtures: Effects on Their Thermal Properties and Morphology

Mixtures of fatty acids and rosin acids are industrially important products utilized as a raw material for several purposes. Their thermal properties, especially cold stability and crystallization behavior is also important. Several fatty acid and rosin acid mixtures both from industrial products and from commercially available fatty and rosin acids were prepared and treated for 30 min at 80 °C under an inert atmosphere. Thereafter, the mixture was cooled to the desired temperature. Determination of the cloud point, chemical analysis of liquid and solid phase, thermal analysis by differential scanning calorimetry as well as morphology analysis by scanning electron microscopy were performed. The results revealed that crystallization was more rapid when it occurred at 10 °C compared to 25 °C. The crystal sizes increased with decreasing the crystallization temperature. Furthermore, crystals were of irregular shape and agglomerated when rapid cooling of the mixture occurred. Chemical analysis revealed that liquid phase was enriched with stearic acid, whereas crystals contained large amounts of abietic, dehydroabietic and linoleic acids. The cloud point of the mixtures increased with increasing amount of stearic and rosin acids. Dehydroabietic acid addition improved the cold stability of the synthetic fatty acid–rosin acids mixture.     

How can we genetically engineer oilseed crops to produce high levels of medium‐chain fatty acids?

The end products of fatty acid synthase activities are usually 16‐ and 18‐carbon fatty acids. There are however, several plant species that store 8‐ to 14‐carbon (medium‐chain) fatty acids in their oil seeds. Among the medium‐chain fatty acids (MCFA), caprylic (8:0) and capric (10:0) are minor components of coconut oil, which are used in many industrial, nutritional and pharmaceutical products. Engineering crop plants such as Brassica could provide an economical source of these oils. During the last decade many laboratories have identified, cloned and characterized both the biosynthetic and catabolic enzymes regulating the composition and levels of these unusual fatty acids in seed oil. Among the biosynthetic enzymes thioesterases (TE), β‐ketoacyl‐ACP synthases (KAS) and acyltransferases are best characterized. In fact several independent investigators have shown that combined expression of the medium‐chain specific enzymes, specifically, TE, KAS and lysophosphatidic acid acyltransferase (LPAAT) results in the production of significant levels of MCFA in seed that otherwise do not accumulate any medium‐chain fatty acid. However, any additional increase in the levels of MCFA in transgenic seeds will require further detailed studies, such as possible induction of the medium‐chain specific enzymes in β‐oxidation and the glyoxylate pathways. To examine such a possibility, a number of genes involved in the β‐oxidation cycle among them a novel enzyme now designated as ACX3, a medium‐chain specific acyl‐CoA‐oxidase, has also been cloned. This article is an attempt to summarize our current knowledge and the present status of engineering oilseed crops for production of medium‐chain fatty acids.     

油脂化学中的转移置换作用

转移置换是一种具有诱人特性的反应类型，用于将油脂原料转化为有用化学产品。为不饱和脂肪酸酯的转移置换作用提供了一种由不饱和二酯合成聚合和特殊化学物质的方便途径。与烯烃交叉转移置换意味着改变脂肪酸的链长生成新的衍生物；与乙烯交叉转移置换得到具有链端双键的化合物，这类物质用途广泛，脂肪油或三甘酯的烯醇式分解把具有长链脂肪酸的三甘酯变成低分子量的油脂。某些高选择性的均相或非均相催化系统对不饱和酯的转移置换作用具有很好的催化效果。尤其是经过改性的非均相铑基和钼基催化剂较为引人注意，考虑到催化剂的活化和再生工序，铑基催化剂可能是最理想的催化系统。