Lipases at interfaces : a review
TL;DR: The presented characterization of the interfacial composition and its consequences provide a new approach for the understanding of lipase reactions at interfaces with direct impact on biotechnological and health care applications.
Abstract: Lipases are acyl hydrolases that play a key role in fat digestion by cleaving long-chain triglycerides into polar lipids Due to an opposite polarity between the enzyme (hydrophilic) and their substrates (lipophilic), lipase reaction occurs at the interface between the aqueous and the oil phases Hence, interfaces are the key spots for lipase biocatalysis and an appropriate site for modulating lipolysis Surprisingly enough, knowledge about the effects of the interfacial composition on lipase catalysis is still limited and only described by the term "interfacial quality" Recent systematic studies based on a biophysical approach allowed for the first time to show the effects of the interfacial microenvironment on lipase catalysis These studies demonstrate that lipase activity as a function of interfacial composition is more attributed to substrate inaccessibility rather than to enzyme denaturation or inactivation, as it is often hypothesized A detailed analysis of the interfacial properties of all compounds involved in triglyceride digestion revealed that lipolysis is a self-regulated reaction This feedback mechanism can be explored as a new avenue to control lipase catalysis To substantiate this hypothesis, oil hydrolysis in a model gastro-intestinal system was performed, which can be seen as an interfacial engineering approach to enzyme reactivity control The presented characterization of the interfacial composition and its consequences provide a new approach for the understanding of lipase reactions at interfaces with direct impact on biotechnological and health care applications
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TL;DR: The advantages and disadvantages of the different existing immobilization strategies to solve the different aforementioned enzyme limitations are given and some advice to select the optimal strategy for each particular enzyme and process is given.
Abstract: Enzyme biocatalysis plays a very relevant role in the development of many chemical industries, e.g., energy, food or fine chemistry. To achieve this goal, enzyme immobilization is a usual pre-requisite as a solution to get reusable biocatalysts and thus decrease the price of this relatively expensive compound. However, a proper immobilization technique may permit far more than to get a reusable enzyme; it may be used to improve enzyme performance by improving some enzyme limitations: enzyme purity, stability (including the possibility of enzyme reactivation), activity, specificity, selectivity, or inhibitions. Among the diverse immobilization techniques, the use of pre-existing supports to immobilize enzymes (via covalent or physical coupling) and the immobilization without supports [enzyme crosslinked aggregates (CLEAs) or crystals (CLECs)] are the most used or promising ones. This paper intends to give the advantages and disadvantages of the different existing immobilization strategies to solve the different aforementioned enzyme limitations. Moreover, the use of nanoparticles as immobilization supports is achieving an increasing importance, as the nanoparticles versatility increases and becomes more accessible to the researchers. We will also discuss here some of the advantages and drawbacks of these non porous supports compared to conventional porous supports. Although there are no universal optimal solutions for all cases, we will try to give some advice to select the optimal strategy for each particular enzyme and process, considering the enzyme properties, nature of the process and of the substrate. In some occasions the selection will be compulsory, for example due to the nature of the substrate. In other cases the optimal biocatalyst may depend on the company requirements (e.g., volumetric activity, enzyme stability, etc).
1,378 citations
TL;DR: There is a need for edible delivery systems to encapsulate, protect and release bioactive and functional lipophilic constituents within the food and pharmaceutical industries, and emulsion technology is particularly suited for the design and fabrication of delivery systems for lipids.
Abstract: There is a need for edible delivery systems to encapsulate, protect and release bioactive and functional lipophilic constituents within the food and pharmaceutical industries. These delivery systems could be used for a number of purposes: controlling lipid bioavailability; targeting the delivery of bioactive components within the gastrointestinal tract; and designing food matrices that delay lipid digestion and induce satiety. Emulsion technology is particularly suited for the design and fabrication of delivery systems for lipids. In this article we provide an overview of a number of emulsion-based technologies that can be used as edible delivery systems by the food and other industries, including conventional emulsions, nanoemulsions, multilayer emulsions, solid lipid particles, and filled hydrogel particles. Each of these delivery systems can be produced from food-grade (GRAS) ingredients (e.g., lipids, proteins, polysaccharides, surfactants, and minerals) using relatively simple processing operations (e.g., mixing, homogenizing, and thermal processing). The structure, preparation, and utilization of each type of delivery system for controlling lipid digestion are discussed. This knowledge can be used to select the most appropriate emulsion-based delivery system for specific applications, such as encapsulation, controlled digestion, and targeted release.
746 citations
TL;DR: Glutaraldehyde, an apparently old fashioned reactive, remains the most widely used and with broadest application possibilities among the compounds used for the design of biocatalyst.
Abstract: Glutaraldehyde is one of the most widely used reagents in the design of biocatalysts. It is a powerful crosslinker, able to react with itself, with the advantages that this may bring forth. In this review, we intend to give a general vision of its potential and the precautions that must be taken when using this effective reagent. First, the chemistry of the glutaraldehyde/amino reaction will be commented upon. This reaction is still not fully clarified, but it seems to be based on the formation of 6-membered heterocycles formed by 5 C and one O. Then, we will discuss the production of intra- and inter-molecular enzyme crosslinks (increasing enzyme rigidity or preventing subunit dissociation in multimeric enzymes). Special emphasis will be placed on the preparation of cross-linked enzyme aggregates (CLEAs), mainly in enzymes that have low density of surface reactive groups and, therefore, may be problematic to obtain a final solid catalyst. Next, we will comment on the uses of glutaraldehyde in enzymes previously immobilized on supports. First, the treatment of enzymes immobilized on supports that cannot react with glutaraldehyde (only inter and intramolecular cross-linkings will be possible) to prevent enzyme leakage and obtain some enzyme stabilization via cross-linking. Second, the cross-linking of enzymes adsorbed on aminated supports, where together with other reactions enzyme/support crosslinking is also possible; the enzyme is incorporated into the support. Finally, we will present the use of aminated supports preactivated with glutaraldehyde. Optimal glutaraldehyde modifications will be discussed in each specific case (one or two glutaraldehyde molecules for amino group in the support and/or the protein). Using preactivated supports, the heterofunctional nature of the supports will be highlighted, with the drawbacks and advantages that the heterofunctionality may have. Particular attention will be paid to the control of the first event that causes the immobilization depending on the experimental conditions to alter the enzyme orientation regarding the support surface. Thus, glutaraldehyde, an apparently old fashioned reactive, remains the most widely used and with broadest application possibilities among the compounds used for the design of biocatalyst.
639 citations
TL;DR: The main uses of the lipase from Thermomyces laguginosus will be revised, with special emphasis in the modification of fats and oils, production of biodiesel, resolution of racemic mixtures, enantioselective hydrolysis of prochiral esters and regioselectives process involving sugar preparations.
Abstract: The lipase from Thermomyces laguginosus (formerly Humicola laguginosa) (TLL) is a basophilic and noticeably thermostable enzyme, commercially available in both soluble and immobilized form. Although initially oriented toward the food industry, the enzyme has found applications in many different industrial areas, from biodiesel production to fine chemicals (mainly in enantio and regioselective or specific processes). This review intends to show some of the most relevant aspects of the use of this interesting enzyme. After checking the enzyme features, some of the most efficient methods of TLL immobilization will be commented. Finally, the main uses of the enzyme will be revised, with special emphasis in the modification of fats and oils, production of biodiesel, resolution of racemic mixtures, enantioselective hydrolysis of prochiral esters and regioselective process involving sugar preparations. In many instances, TLL has been compared to other lipases, the advantages or disadvantages of the enzyme will be discussed.
510 citations
TL;DR: In this paper, food emulsion structure and stability has been investigated in terms of its role in lipid metabolism and metabolism, and it has been shown that food emulsions have a contributing role on lipid digestion and metabolism.
Abstract: The digestion and metabolism of lipids continues to generate considerable scientific interest, with food emulsions increasingly being seen as a mechanism by which lipid uptake may be controlled. Scientific advancement in this field is partly being driven by the ongoing need to address the obesity crisis, for which the enhancement of satiety and/or reduction of energy intake is seen as a positive solution in achieving more effective weight management. Yet the ability to regulate lipid uptake is also seen as beneficial in other areas, such as improved nutrition for the young and/or elderly and in cardiovascular protection. Because of the complexity of food digestion, the majority of research in this area has been applied to model or highly controlled systems. Through this approach it is becoming increasingly apparent that food emulsion structure and stability does have a contributing role on lipid digestion and metabolism. There is now a clear indication of how emulsion stability within the stomach affects emptying rates. There have been considerable developments in understanding the relationship between interfacial composition and lipolysis in both the gastric and intestinal regions, and how this relates to lipid uptake/metabolism. There is also an emerging understanding of the contribution of gastrointestinal biophysics to emulsion structure and stability, and how intestinal motility is in turn impacted by structural aspects, such as relative changes in particle size. Understanding of lipid digestion has been progressed through recent advancements in the sophistication of in vitro models. These are now seen as providing a more realistic representation of physiological conditions, both in terms of biochemical environment, and the biophysics of the gastrointestinal tract. Improvements in the validity of such models against in vivo and clinical behaviours is allowing aspects of emulsion digestion to be observed without the immediate need of costly human trials. Accordingly, emulsion systems with increasing structural complexity are now able to be characterised in terms of digestion behaviours. The ability to design food emulsions with specific lipid digestion profiles may allow the development of mainstream foods with particular physiological properties, such as enhanced satiation, or targeted delivery.
492 citations
Cites background from "Lipases at interfaces : a review"
...The regulation of lipid bioavailability is receiving increasing attention because of the need to more effectively manage the nutritional value of our food [1–6]....
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...2i) [4,21–23,30]....
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References
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1,798 citations
TL;DR: Various industrial applications of microbial lipases in the detergent, food, flavour industry, biocatalytic resolution of pharmaceuticals, esters and amino acid derivatives, making of fine chemicals, agrochemicals, use as biosensor, bioremediation and cosmetics and perfumery are described.
Abstract: Lipases are a class of enzymes which catalyse the hydrolysis of long chain triglycerides. Microbial lipases are currently receiving much attention with the rapid development of enzyme technology. Lipases constitute the most important group of biocatalysts for biotechnological applications. This review describes various industrial applications of microbial lipases in the detergent, food, flavour industry, biocatalytic resolution of pharmaceuticals, esters and amino acid derivatives, making of fine chemicals, agrochemicals, use as biosensor, bioremediation and cosmetics and perfumery.
1,753 citations
TL;DR: In this paper, a general theory of diffusion to the surface is derived, which allows for back-diffusion and which makes no special assumptions of a physical nature, and the methods of this theory are applied to analyze recent data on time-effects of short duration.
Abstract: The variation of surface tension of solutions with time has in some cases, where the change is over within a few seconds or less, been explained on the basis of diffusion. This paper attempts a rigorous mathematical analysis of the role that diffusion might play in such time‐effects. The limitations of diffusion theories which have been proposed previously are discussed. A general theory of diffusion to the surface is derived, which allows for back‐diffusion and which makes no special assumptions of a physical nature. It is possible to use Fick's equation to calculate the total amount of solute which diffuses from a semi‐infinite bulk solution into the surface if the concentration immediately under the surface is known at various times throughout the process. It is shown how the latter information may be deduced from the variation of surface tension with time together with final equilibrium values of surface tension. The methods of this theory are applied to analyze recent data on time‐effects of short duration. It is concluded that even in cases where the variation of the surface tension is over in less than a second the rate‐determining process is not diffusion. Even for these very rapid changes one is therefore led to assume the existence of an activation barrier which determines the rate of adsorption.
1,263 citations
TL;DR: Thermodynamic analysis reveals that, under many conditions, the adsorption is driven by an entropy increase that is (partly) related to changes in the structure of the protein molecules.
Abstract: The purpose of this article is to present some general principles and rules for the adsorption of proteins from aqueous solution on solid surfaces, emphasizing conformational and reversibility aspects. Special attention is paid to the relation between structural properties of the protein molecule and its adsorption behavior and to the role of small ions in the overall adsorption process. Thermodynamic analysis reveals that, under many conditions, the adsorption is driven by an entropy increase that is (partly) related to changes in the structure of the protein molecules.
1,059 citations
Book•
01 Jan 2017
TL;DR: In this paper, the SI rules for notation for SI units are discussed. But the SI Units System is not defined. And the SI Rule for Notation for SI Quantities is not discussed.
Abstract: Introduction Aspects of Thermodynamics Bonds and Interaction Forces Reaction Kinetics Transport Phenomena Polymers Proteins Water Relations Dispersed Systems Surface Phenomena Formation of Emulsions and Foams Colloidal Interactions Changes in Dispersity Nucleation Crystallization Glass Transitions And Freezing Soft Solids APPENDIX A: Frequently Used Symbols for Physical Quantities APPENDIX B: Some Frequently Used Abbreviations APPENDIX C: Some Mathematical Symbols APPENDIX D: SI Rules for Notation APPENDIX E: The SI Units System APPENDIX F: Some Conversion Factors APPENDIX G: Recalculation of Concentrations APPENDIX H: Physical Properties of Water at 0-100 C APPENDIX I: Thermodynamic and Physical Properties of Water and Ice APPENDIX J: Some Values of the Error Function Index
860 citations
"Lipases at interfaces : a review" refers background in this paper
...Proteins can be said to be much more interfacial active than low molecular weight surfactants since the molar bulk concentration needed to reach interfacial saturation differs by many orders of magnitude [56]....
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...Bile salts have been shown to inhibit lipolysis of triglycerides near the critical micelle concentration [56]....
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