Enzymatic biodiesel production: Technical and economical considerations

It is well documented in the literature that enzymatic processing of oils and fats for biodiesel is technically feasible. However, with very few exceptions, enzyme technology is not currently used in commercial‐scale biodiesel production. This is mainly due to non‐optimized process design and a lack of available cost‐effective enzymes. The technology to re‐use enzymes has typically proven insufficient for the processes to be competitive. However, literature data documenting the productivity of enzymatic biodiesel together with the development of new immobilization technology indicates that enzyme catalysts can become cost effective compared to chemical processing. This work reviews the enzymatic processing of oils and fats into biodiesel with focus on process design and economy.     

Prospects for application of enzymatic interesterification of oils in the production of modified fats

This review discusses a recent state of research in the field of enzymatic biocatalysis in application for the production of modified food fats. Properties of biocatalysts for enzymatic interesterification both been currently under development and already applied in industry of vegetable oils are discussed. The main directions of research on development of new biocatalysts, including those based on the novel recombinant lipase enzymes, as well as the potential of targeted modifications in the composition of oils by optimization of the catalytic process are covered. The relevant analysis of the enzymatic interesterification of oils shows its potential for development of energy efficient and environmentally friendly processes for production of the high quality food products with the specified characteristics.     

Lipase-catalyzed interesterification of oils and fats

Extracellular microbial lipases can be used as catalysts for the interesterification of oils and fats. Use of specific lipases gives products which are unobtainable by chemical interesterification methods. Some of these products have properties of value to the oils and fats industry. The catalysts for enzymatic interesterification are prepared by coating inorganic support materials with the lipases. For batch interesterification reactions, the catalyst particles are activated by addition of a small amount of water and then stirred with a reactant mixture dissolved in petroleum ether. At the end of the reaction period, the catalyst particles are removed by filtration, and the interesterified triglycerides isolated by conventional fat fractionation techniques. The catalyst can be used in subsequent batch reactions. As an alternative to the batch reaction system, continuous enzymatic interesterification processes can be operated by pumping water containg feedstock through a packed bed of activated catalyst.     

酶催化油脂水解技术新进展及发展趋势

介绍了近年来内化油脂水解国内外技术新进展,生物反应器在油脂酶水解中的应用,酶固定在载体上的脂肪酶水解油脂及发展趋势。     

Interchangeability of fats and Oils

The requirement for interchangeability of fats and oils is a result of such factors as availability and cost of raw materials, and the effects of legislation or market preference on product composition. Such changes should not affect the product’s quality or performance. Interchangeability is practiced today in the production of products for human food, animal feed and technical uses, and is frequently controlled by computer. It is necessary fully to identify a product and its essential features whether simply by melting point or a full triglyceride structure. Modern analytical techniques such as NMR, GC, HPLC and DSC have enabled this identification to become a more exact science. The interchange may consist of a simple substitution of one oil or fat for another, or it may be more complex, involving a number of oils and fats and processes. Finally, the nature of the product may be such that it has to be “tailor-made” using sophisticated processes to produce the required triglyceride composition. The unit processes which are employed are blending, hydrogenation, fractionation and interesterification. In the last process the recently published use of enzymes is of particular interest. Problems encountered are mainly concerned with the polymorphism of fats and oils which frequently sets limits on the proportion of a particular fat which can be used. Limits are also imposed by plant processing capacity. Palm and lauric acid oils are particularly important in the context of interchangeability for both edible and technical purposes because of their fatty acid and triglyceride compositions. They provide good examples of usefulness, problems resulting from polymorphism and the difficulties of substitution.     

Stability of Emulsions Containing Interesterified Fats Based on Mutton Tallow and Walnut Oil

In this work, modified fats were produced by enzymatic interesterification of mutton tallow with walnut oil. As a result of forcing the fat hydrolysis process by addition of water to the enzymatic preparation (11.5, 13.0, 14.5, 16.0 wt %), additional levels of polar fractions (MAGs, DAGs, and FFAs) were observed. The aim of this work was to evaluate the stability of emulsions of modified fats containing natural emulsifiers resulting from enzymatic interesterification of mutton tallow with walnut oil. The physical‐chemical parameters of obtained fats were determined in this study. Using several methods, the stability of the formed emulsions was also evaluated. The results showed that the fats resulting from interesterification in the presence of Lipozyme RM IM (immobilized lipase from Rhizomucor miehei, Novozymes Bagsvaerd, Denmark) with 13.0, 14.5, and 16.0 wt % of water in the enzymatic preparation could form stable emulsion systems. On the other hand, the emulsion of the interesterification system where the amount of water in the enzymatic preparation was 11.5 % showed very low stability. The number of natural emulsifiers (MAGs and DAGs) that arose after interesterification was insufficient to stabilize the emulsion system. The work has shown the possibility of using interesterified fats as the fat phase. Emulsions formed on the basis of interesterified fats without any additional emulsifiers such as sunflower lecithin had properties comparable to emulsions containing mixed non‐interesterified fat containing additional emulsifier. The natural emulsifiers formed as part of enzymatic interesterification allow formation of stable emulsion systems.     

Oils and fats,the historical cosmetics

Many of the uses of oils and fats in cosmetics are the same as those of antiquity. However, technical progress has taken these natural materials apart and put them together differently. So now cosmetic chemists have the advantages of both natural and man-made fats and oils. Furthermore, today there are available a variety of antioxidants which extend the shelf life of cosmetics made with them.     

Biotechnology as Applied to the Oils and Fats Industry

Three areas where biotechnology is applicable to the oils and fats industry are described. 1. Biotechnology and oil plants includes the cloning of high-yielding trains of oil palms to yield progeny in large numbers relatively quickly. Mutation of oilseeds to change the fatty acid composition is also being carried out in various laboratories. 2. Biotechnology with enzymes encompasses the use of microbial lipases for the interesterification of triacylglycerols to form cocoa butter substitutes, as well as the use of lipases to hydrolyse selectively particular fatty acyl esters. Some industrial developments in these areas appear imminent. 3. Biotechnology with micro-organisms can be seen as an alternative means of producing oils and fats to existing routes though the economics are against such processes being taken up for all but the most expensive oils and fats. A range of oils can, however, be produced by bacteria, algae, yeasts and moulds. Micro-organisms can also be used to transform alkanes and fatty acids to provide various fatty acid derivatives which could be of value. The biochemistry behind lipid accumulation is described. This provides an understanding of the regulatory enzymes which need to be controlled in order to achieve high accumulations of lipids. From such information, it then becomes possible to consider metabolic manipulation of the organism to improve its fat yield. By extension of these arguments, possible opportunities for genetic engineering into both micro-organisms and plants then become evident.     

The application of biotechnological methods for the synthesis of biodiesel

Synthesis of biodiesel is performed mainly by chemical catalysis, but can also be performed by enzymatic or microbial methods, and these might play an important role in future substitution of petroleum‐based diesel. To discover sustainable, economically attractive biotechnological processes for biodiesel synthesis, close cooperation between different disciplines is needed. Currently, lipases are the enzymes of choice for the synthesis of fatty acid esters (FAE) from fats and oils, yielding biodiesel with the methyl esters (FAME) as the most important product. More recently, the direct production of FAE using engineered whole cell microorganism has also been described (MicroDiesel). Current enzymatic processes are still hampered by the high costs of the biocatalyst, but significant progress has recently been made leading to the first industrial enzymatic biodiesel production. Enzymatic biodiesel production is mostly attractive because of the starting materials (waste frying oils, oils with high water content, etc.), for which conventional chemical interesterification can hardly be applied.     

Möglichkeiten der Fettchemie für die Schmiermittelindustrie

Feasibilities of the Fat Chemistry for the Lubricant Industry Animal and vegetable fats and oils have been used for centuries as lubricants. Only the industrialization and motorization led to an immense increase of the consumption of the lubricants which amount today about 1.3 million tons a year only in the Federal Republic of Germany. The mineral oil represents now the most important raw material. Therefore the question arises what contribution the fat chemistry can give today for the lubricant industry to accomplish its various tasks. Feasibilities of the fat chemistry to refine oils and fats furtheron to suitable formulation components for the lubricant industry are pointed out. Thereby actual problems and development tendencies are discussed, which are correlated with the matter of lubricants and are nowadays generally discussed.     

Enzymatische Fettspaltung

Enzymatic Fat Splitting The splitting of fats and oils by high-pressure steam is a well-established technical process. Nevertheless the enzymatic hydrolysis of fats still remains a promising alternative due to possible savings of energy, increased product-selectivity and the reduced thermal damage to the reactants. Furthermore fats, as renewable raw materials, will gain in importance as substrates for technical processes. On the other hand the product-added value from the fat-splitting process is low compared to many other processes especially in the pharmaceutical field. Kinetic data of practical relevance are rare in this field. The purpose of this work was therefore to fill this gap. Under technically relevant conditions a conversion of at least 95% is achieved for soybean or olive oil by enzymatic fat-splitting in a stirred tank-reactor on a laboratory scale. The concentration of glycerol in water is influenced by the ratio of the fat and water phase and turnes out to be of great importance. Among the more than thirty microbial lipases tested, an enzyme from Candida cylindracea is most suitable for total hydrolysis: it shows a broad substrate specificity at a high specific activity and cleaves all three ester-bonds at similar rates. Technically important fats and oils are also readily accepted as substrates. The influence of the interfacial surface area between oil and water phase is quantitatively measured and interpretated. The rate of hydrolysis is determined during batchwise as well as continuous operation. Under both process conditions severe product inhibition is observed. The thermodynamic and kinetic results indicate that a reactor concept of the counter-current plug-flow type would be most suitable. The stability and the price of the enzyme seem to be the major factors limiting the development of an economic enzymatic fatsplitting process.     

Fette als Rohstoff der Lackindustrie

Fats as Raw Materials for Paint Industry Fats are even today important raw materials for the paint industry. Roughly one tenth of the world production of fatty matter is processed for paints. More than 50% of paints in the true sense are manufactured on fat basis; thereby linseed oil plays a dominating role. With reference to the total amount of paints produced in Germany, the proportion of fats employed decreased from ca. 36% to 27% in the last ten years inspite of an increase in the absolute amount of fats (64% increase). Simultaneously, a considerable increase took place in the proportion of oil-free synthetic resin paints. The possible causes of these displacements in proportions are discussed. Apart from their customary uses, special fat-products have found new fields of application in paints, i. e. reactive paints, and hence in the forthcoming decade one may expect fats to constitute 50% of raw materials for paints. The steadily increasing demand for edible fats leads to thoughts, regarding how the fats that are suitable for human nutrition should be secured for this particular sphere without impairing the supply of fats for technical purposes.     

Glycerin - Ein fettchemischer Grundstoff im Wandel der Zeit

Glycerine - The History of an Oleochemical Raw Material Being a constituent of all fats and oils, natural glycerine has always played a key role in oleochemical manufacturing processes. Owing to its special physical and chemical properties, glycerine, which is obtained as a byproduct in neutral oil saponification and in the splitting and transesterification of fats and oils, has succeeded in becoming established and gaining in importance even under changing economic conditions. The major part of glycerine and its derivatives produced worldwide is nowadays used in the cosmetic and pharmaceutical industries, the food and tabacco industries, and in plastics manufacturing. Often its lack in color and odor and the fact that it presents no health hazards are of decisive importance. The range of applications is accordingly very wide. The current world consumption is estimated at about 500000 tons per year. Therefore the useful and economically efficient production, processing and marketing of this valuable oleochemical raw material continues to be one of the focal activities of the chemical industry today.     

油脂的化学和生物转化研究进展

综述了近年来发现的一些新型脂肪酸的结构和应用,以及游离脂肪酸包括长链脂肪酸、ω-羟基脂肪酸和ω-不饱和脂肪酸的合成与化学转化现状,概述了生物学方法特别是酶催化法在油脂转化方面的研究进展。     

Enzymic Modification at the Mid-Chain of Fatty Acids

The enzyme systems responsible for the range of mid-chain modifications of natural fatty acids could be considered for industrial scale exploitation. Regio- and stereospecificity of enzymes allows control over products. Unsaturated fatty acids are common oxidation substrates with oxidoreductases giving hydroxy-, epoxy-, hydroperoxy-, keto- and dihydroxy fatty acids. Some products may be of fairly high value (e. g. prostaglandins) although most should be considered as commodity chemicals. Unsaturated fatty acids may be reduced by enzymes found in rumen microorganisms. This example and others are used to illustrate the importance of the nature of the biocatalyst in considering an overall process. Whole cells are likely to be far more suitable than isolate enzymes for processes involving multiple redox steps (e. g. biohydrogenation, some oxidations) although lipoxygenases can function effectively as isolated enzymes giving a range of products suitable for further enzymic or chemical modification. Some enzymes such as hydratases give hydroxy-fatty acids without the need for cofactors and could be used either in whole cells or as isolated enzymes. A major obstacle in the exploitation of biocatalysis in the fats and oils industry concerns the difficulty of developing reactor systems appropriate to reacting the organic feedstream with a hydrophilic enzyme or whole cell catalyst.     

Vermeidbare und verwertbare Abfallprodukte in der Fettindustrie

Avoidable and Unavoidable Wastes of the Fat Industry During the storage, transport, recovery and processing of raw materials for fats waste materials are formed in all possible states of aggregation and mixtures. They range from dust and tank sediments of various processing steps to paper and plastic wastes from packaging material. Most of these wastes are today either avoidable, or, if unavoidable, they can be utilized. Practical examples of this specific problem are given and economical and technological aspects are discussed.     

Gas-liquid chromatography of lipids,carbohydrates and amino acids

Gas-liquid chromatography is primarily a powerful separating tool. Compounds can be trapped as they emerge from the GLC apparatus for analysis by mass spectrometry and infrared or ultraviolet spectrophotometry, or the emerging separated components may flow directly into one of these instruments making positive identification of the components possible. Quantitative analyses of fats and oils are possible when certain requirements are observed. A combination of fatty acid, triglyceride and sterol analyses offers promise of a rapid means for the identification of fats and oils and their admixture or adulteration. Progress has been made on the preparation of derivatives of carbohydrates and amino acids such that these compounds may soon be analyzed as readily by GLC as lipids are today. Presented at the AOCS-AACC Joint Meeting, Washington, D.C., April 1968. E. Utiliz. Res. Dev. Div., ARS, USDA.     

Role of Metabolism in Bone Development and Homeostasis

Carbohydrates, fats, and proteins are the underlying energy sources for animals and are catabolized through specific biochemical cascades involving numerous enzymes. The catabolites and metabolites in these metabolic pathways are crucial for many cellular functions; therefore, an imbalance and/or dysregulation of these pathways causes cellular dysfunction, resulting in various metabolic diseases. Bone, a highly mineralized organ that serves as a skeleton of the body, undergoes continuous active turnover, which is required for the maintenance of healthy bony components through the deposition and resorption of bone matrix and minerals. This highly coordinated event is regulated throughout life by bone cells such as osteoblasts, osteoclasts, and osteocytes, and requires synchronized activities from different metabolic pathways. Here, we aim to provide a comprehensive review of the cellular metabolism involved in bone development and homeostasis, as revealed by mouse genetic studies.     

Lard‐based fats healthier than lard: Enzymatic synthesis,physicochemical properties and applications

Lard has long been deemed superior to vegetable oils for culinary purposes due to its exceptional properties such as wide plastic range and special flavor values. Nevertheless, its usage over the years has seen a marked decrease due to awareness of its negative nutritional values such as high calorific content (see below) and saturated fatty acids. This paper looks into the possibilities of producing healthier lard‐based fats through “green” biocatalysis methods with particular attention given to the technical challenges of the process and their possible solutions. Alterations in physicochemical properties and application practicability of the modified lard‐based fats are also carefully elucidated.     

Enzymatic interesterification of tallow-sunflower oil mixtures

In an effort to improve the physical and/or thermal characteristics of solid fats, the enzymatic interesterification of tallow and butterfat with high-oleic sunflower oil and soybean oil was investigated. The two simultaneously occurring reactions, interesterification and hydrolysis, were followed by high-performance liquid chromatography of altered glycerides and by gas-liquid chromatography of liberated free fatty acids. The enzymes used in these studies were immobilized lipases that included either a 1,3-acyl-selective lipase or acis-9-C₁₈-selective lipase. The degree of hydrolysis of the fat/oil mixtures was dependent upon the initial water content of the reaction medium. The extent of the interesterification reaction was dependent on the amount of enzyme employed but not on the reaction temperature over the range of 50–70°C. Changes in melting characteristics of the interesterified glyceride mixtures were followed by differential scanning calorimetry of the residual mixed glycerides after removal of free fatty acids. Interesterification of the glyceride mixes with the two types of enzymes allowed for either a decrease or increase in the solid fat content of the initial glyceride mix.