Lipase Catalysis in Mixed Micelles
31 Mar 2022-ChemBioEng reviews-Vol. 9, Iss: 4, pp 409-418
TL;DR: In this paper , the catalytic performance of lipase, an interfacially active enzyme, depends on the reaction medium, such as mixture of mixed micelles, which have advantages like improving lipase-substrate interaction, increasing water nucleophilicity, sometimes greater emulsion stability and reduced product inhibition.
Abstract: The catalytic performance of lipase, an interfacially active enzyme, depends on the reaction medium. Novel reaction media like mixed micelles affect lipase catalysis mostly by stabilizing the lipase structure and increasing the substrate solubilization. Nonionic surfactant addition in ionic micelles formed mixed micelles and increased lipase catalysis by lowering detrimental lipase-ionic surfactant hydrophobic and electrostatic interactions. Nonionic/nonionic mixed micelles enhanced activity and enantiomeric selectivity of free lipase but reduced those for immobilized lipase. Nonconventional cationic/cationic, anionic/nonionic/ionic liquid, and substrate/nonionic mixed micelles also improved lipase catalysis. Lipase activity was high in bile salt/surfactant mixed micelles but was low in bile salt/phospholipid mixed micelle. Mixed micelles have advantages like improving lipase-substrate interaction, increasing water nucleophilicity, sometimes greater emulsion stability, and reduced product inhibition. In mixed micelles, increasing the lipase concentration can overcome the problem regarding inaccessibility of insoluble substrates.
TL;DR: The use of microbial lipases in a variety of industrial processes is discussed in this article , where the authors provide a critical analysis of lipase-producing microbes, distinguished from the previously published reviews, and illustrate their role in bioremediation and racemization.
Abstract: Lipases are versatile biocatalysts and are used in different bioconversion reactions. Microbial lipases are currently attracting a great amount of attention due to the rapid advancement of enzyme technology and its practical application in a variety of industrial processes. The current review provides updated information on the different sources of microbial lipases, such as fungi, bacteria, and yeast, their classical and modern purification techniques, including precipitation and chromatographic separation, the immunopurification technique, the reversed micellar system, aqueous two-phase system (ATPS), aqueous two-phase flotation (ATPF), and the use of microbial lipases in different industries, e.g., the food, textile, leather, cosmetics, paper, and detergent industries. Furthermore, the article provides a critical analysis of lipase-producing microbes, distinguished from the previously published reviews, and illustrates the use of lipases in biosensors, biodiesel production, and tea processing, and their role in bioremediation and racemization.
TL;DR: In this paper , a comprehensive overview of the self-assembly of bile salts emphasizing their mixed smart aggregates with a variety of amphiphiles is presented, which can enable the development of new strategies for improving the bioavailability of drugs solubilized in newly developed potential hosts.
Abstract: The present communication offers a comprehensive overview of the self-assembly of bile salts emphasizing their mixed smart aggregates with a variety of amphiphiles. Using an updated literature survey, we have explored the dissimilar interactions of bile salts with different types of surfactants, phospholipids, ionic liquids, drugs, and a variety of natural and synthetic polymers. While assembling this review, special attention was also provided to the potency of bile salts to alter the size/shape of aggregates formed by several amphiphiles to use these aggregates for solubility improvement of medicinally important compounds, active pharmaceutical ingredients, and also to develop their smart delivery vehicles. A fundamental understanding of bile salt mixed aggregates will enable the development of new strategies for improving the bioavailability of drugs solubilized in newly developed potential hosts and to formulate smart aggregates of desired morphology for specific targeted applications. It enriches our existing knowledge of the distinct interactions exerted in mixed systems of bile salts with variety of amphiphiles. By virtue of this, researchers can get innovative ideas to construct novel nanoaggregates from bile salts by incorporating various amphiphiles that serve as a building block for smart aggregates for their numerous industrial applications.
TL;DR: In this article, the authors highlight several aspects of lipase-catalyzed biodiesel production and discuss the possible solutions to circumvent the well-known problems inherent in these systems, such as the low-stability and the pricing of biocatalysts.
Abstract: The rising global demand for sustainable energy resources is resulting in an accelerated increase in biodiesel consumption. In this sense, studies aimed at tackling process hurdles in biodiesel production have been continuously carried out. In order to reduce energy consumption and the amount of wastewater generated, as well as to avoid the production of inefficient end products, classes of enzymes, especially lipases, are being successfully explored as substitutes to chemical catalysts. This article highlights several aspects of lipase-catalyzed biodiesel production. The recent advances and the future perspectives of mechanisms that could circumvent the well-known problems inherent in these systems are presented and discussed, such as the low-stability and the pricing of biocatalysts. According to the literature, alternative solutions include the use of low-cost, unconventional raw materials, new supports, the elucidation of mechanisms of lipase immobilization, and optimal designs and operational settings for bioreactors. Finally, there is a discussion around the necessary steps to enable an economically-viable industrial production.
TL;DR: Examples of the various effects of surfactants on lipase structure, activity and inhibition are reviewed, which show how complex the various equilibria involved in the lipolysis reaction tend to be.
Abstract: Lipase inhibitors are the main anti-obesity drugs prescribed these days, but the complexity of their mechanism of action is making it difficult to develop new molecules for this purpose. The efficacy of these drugs is known to depend closely on the physico-chemistry of the lipid-water interfaces involved and on the unconventional behavior of the lipases which are their target enzymes. The lipolysis reaction which occurs at an oil-water interface involves complex equilibria between adsorption-desorption processes, conformational changes and catalytic mechanisms. In this context, surfactants can induce significant changes in the partitioning of the enzyme and the inhibitor between the water phase and lipid-water interfaces. Surfactants can be found at the oil-water interface where they compete with lipases for adsorption, but also in solution in the form of micellar aggregates and monomers that may interact with hydrophobic parts of lipases in solution. These various interactions, combined with the emulsification and dispersion of insoluble substrates and inhibitors, can either promote or decrease the activity and the inhibition of lipases. Here, we review some examples of the various effects of surfactants on lipase structure, activity and inhibition, which show how complex the various equilibria involved in the lipolysis reaction tend to be.
TL;DR: In this paper, a straightforward chemoenzymatic synthesis of (S)-Pindolol has been developed, where the key step involved the enzymatic kinetic resolution of rac-2-acetoxy-1-(1H-indol-4-yloxy)-3-chloropropane with lipase from Pseudomonas fluorescens via hydrolytic process to obtain enantiomerically enriched halohydrin (2S)-1.
Abstract: A straightforward chemoenzymatic synthesis of (S)-Pindolol has been developed. The key step involved the enzymatic kinetic resolution of rac-2-acetoxy-1-(1H-indol-4-yloxy)-3-chloropropane with lipase from Pseudomonas fluorescens via hydrolytic process to obtain enantiomerically enriched halohydrin (2S)-1-(1H-indol-4-yloxy)-3-chloro-2-propanol (96% ee) and (2R)-2-acetoxy-1-(1H-indol-4-yloxy)-3-chloropropane (97% ee). The latter was subjected to a hydrolysis reaction catalyzed by Candida rugosa leading to (2R)-1-(1H-indol-4-yloxy)-3-chloro-2-propanol (97% ee), followed by a reaction with isopropylamine, producing (S)-Pindolol (97% ee) in quantitative yield.
TL;DR: The high yield and enantioselectivity of their reactions, regarding the resolution of racemic mixtures, shows that the lipases from Pseudomonas are efficient biocatalysts for biotechnological processes.
Abstract: Lipases from Pseudomonas are extracellular enzymes that play an important role in biotechnological and industrial processes, due to their application in biofuels, food and pharmaceutical industries. Therefore, this paper provides an overview about the main aspects of the lipases from Pseudomonas, regarding their catalytic characterization, production, immobilization and application in many reactions of high industrial interest. The catalytic characterization and production of the lipase will be discussed, including the main lipase properties available in the literature and the influence of media composion, making possible the optimization of lipase production. Based on the main features of the lipases from Pseudomonas , this review also explores the recent developments on strategies of immobilization in order to enable recovery operations of the biocatalyst. The application of lipases to production of many high added-value products through esterifications, hydrolysis reactions and resolution of racemic compounds was also explored. The high yield and enantioselectivity of their reactions, regarding the resolution of racemic mixtures, shows that the lipases from Pseudomonas are efficient biocatalysts for biotechnological processes.
TL;DR: To ascertain the influence of non-ionic surfactants in improving the activity of surface-active enzymes is not limited to lipase only, the catalytic activity of Horseradish peroxidase (HRP) in different mixed W/O microemulsions is investigated.
Abstract: The primary objective of the present study is to understand how the different nonionic surfactants modify the anisotropic interface of cationic water-in-oil (W/O) microemulsions and thus influences the catalytic efficiency of surface-active enzymes. Activity of Chromobacterium viscosum lipase (CV-lipase) was estimated in several mixed reverse micelles prepared from CTAB and four different nonionic surfactants, Brij-30, Brij-92, Tween-20, and Tween-80/water/isooctane/n-hexanol at different z ([cosurfactant]/[surfactants]) values, pH 6 (20 mM phosphate), 25 degrees C across a varying range of W0 ([water]/[surfactants]) using p-nitrophenyl-n-octanoate as the substrate. Lipase activity in mixed reverse micelles improved maximum up to approximately 200% with increasing content of non-ionic surfactants compared to that in CTAB probably due to the reduced positive charge density as well as plummeted n-hexanol (competitive inhibitor of lipase) content at the interfacial region of cationic W/O microemulsions. The highest activity of lipase was observed in CTAB (10 mM) + Brij-30 (40 mM)/isooctane/n-hexanol)/water system, k2 = 913 +/- 5 cm3 g-1 s-1. Interestingly, this observed activity is even higher than that obtained in sodium bis (2-ethyl-1-hexyl) sulfosuccinate (AOT)/n-heptane reverse micelles, the most popular W/O microemulsion in micellar enzymology. To ascertain the influence of non-ionic surfactants in improving the activity of surface-active enzymes is not limited to lipase only, we have also investigated the catalytic activity of Horseradish peroxidase (HRP) in different mixed W/O microemulsions. Here also following the similar trend as observed for lipase, HRP activity enhanced up to 2.5 fold with increasing concentration of nonionic surfactants. Finally, the enzyme activity was correlated with the change in the microenvironment of mixed reverse micelles by steady-state fluorescence study using 8-anilino-1-napthalenesulphonic acid (ANS) as probe.