Oil-water interfacial activation of lipase for interesterification of triglyceride and fatty acid

Substrate specificity of commercial lipases activated by a hydration-aggregation pretreatment in anhydrous esterification reactions

Substrate specificity in non-aqueous esterification catalyzed by commercial lipases activated by hydration-aggregation pretreatment was investigated. Four microbial lipases from Rhizopus japonicus, Burkholderia cepacia, Rhizomucor miehei, and Candida antarctica (fraction B) were used to study the effect of the carbon chain length of saturated fatty acid substrates on the esterification activity with methanol in n-hexane. Hydration-aggregation pretreatment had an activation effect on all lipases used, and different chain length dependencies of esterification activity for lipases from different origins were demonstrated. The effects of various acidic substrates with different degrees of unsaturation, aromatic rings, and alcohol substrates with different carbon chain lengths on esterification activity were examined using R. japonicus lipase, which demonstrated the most remarkable activity enhancement after hydration-aggregation pretreatment. Furthermore, in the esterification of myristic acid with methanol catalyzed by the hydrated-aggregated R. japonicus lipase, maximum reaction rate (5.43 × 10-5 mmol/(mg-biocat min)) and Michaelis constants for each substrate (48.5 mM for myristic acid, 24.7 mM for methanol) were determined by kinetic analysis based on the two-substrate Michaelis-Menten model.

Switchable CO2-Responsive Janus Nanoparticle for Lipase Catalysis in Pickering Emulsion

The use of convertible immobilized enzyme carriers is crucial for biphasic catalytic reactions conducted in Pickering emulsions. However, the intense mechanical forces during the conversion process lead to enzyme leakage, affecting the stability of the immobilized enzymes. In this study, a CO2-responsive switchable Janus (CrSJ) nanoparticle (NP) was developed using silica NP, with one side featuring aldehyde groups and the other side adsorbing N,N-dimethyldodecylamine. A switchable Pickering emulsion catalytic system for biphasic interface reactions was prepared by covalently immobilizing lipase onto the CrSJ NPs. The CO2-responsive nature of the CrSJ NPs allowed for rapid conversion of the Pickering emulsion, and covalent immobilization substantially reduced lipase leakage while enhancing the stability of the immobilization during the conversion process. Impressively, after repeated transformations, the Pickering emulsion still maintains its original structure. Following 10 consecutive cycles of esterification and hydrolysis reactions, the immobilized enzyme's activity remains at 77.7 and 79.5% of its initial activity, respectively. The Km of the CrSJ catalytic system showed no significant change compared to the free enzyme, while its Vmax values were 1.2 and 1.6 times that of the free enzyme in esterification and hydrolysis reactions, respectively.

A comprehensive review on nanocatalysts and nanobiocatalysts for biodiesel production in Indonesia, Malaysia, Brazil and USA

Biodiesel is an alternative to fossil-derived diesel with similar properties and several environmental benefits. Biodiesel production using conventional catalysts such as homogeneous, heterogeneous, or enzymatic catalysts faces a problem regarding catalysts deactivation after repeated reaction cycles. Heterogeneous nanocatalysts and nanobiocatalysts (enzymes) have shown better advantages due to higher activity, recyclability, larger surface area, and improved active sites. Despite a large number of studies on this subject, there are still challenges regarding its stability, recyclability, and scale-up processes for biodiesel production. Therefore, the purpose of this study is to review current modifications and role of nanocatalysts and nanobiocatalysts and also to observe effect of various parameters on biodiesel production. Nanocatalysts and nanobiocatalysts demonstrate long-term stability due to strong Brønsted-Lewis acidity, larger active spots and better accessibility leading to enhancethe biodiesel production. Incorporation of metal supporting positively contributes to shorten the reaction time and enhance the longer reusability. Furthermore, proper operating parameters play a vital role to optimize the biodiesel productivity in the commercial scale process due to higher conversion, yield and selectivity with the lower process cost. This article also analyses the relationship between different types of feedstocks towards the quality and quantity of biodiesel production. Crude palm oil is convinced as the most prospective and promising feedstock due to massive production, low cost, and easily available. It also evaluates key factors and technologies for biodiesel production in Indonesia, Malaysia, Brazil, and the USA as the biggest biodiesel production supply.

Efficiency of an alkaline, thermostable, detergent compatible, and organic solvent tolerant lipase with hydrolytic potential in biotreatment of wastewater

Discharging the tannery wastewater into the environment is a serious challenge worldwide due to the release of severe recalcitrant pollutants such as oil compounds and organic materials. The biological treatment through enzymatic hydrolysis is a cheap and eco-friendly method for eliminating fatty substances from wastewater. In this context, lipases can be utilized for bio-treatment of wastewater in multifaceted industrial applications. To overcome the limitations in removing pollutants in the effluent, we aimed to identify a novel robust stable lipase (PersiLipase1) from metagenomic data of tannery wastewater for effective bio-degradation of the oily wastewater pollution. The lipase displayed remarkable thermostability and maintained over 81 % of its activity at 60 °C.After prolonged incubation for 35 days at 60°C, the PersiLipase1 still maintained 53.9 % of its activity. The enzyme also retained over 67 % of its activity in a wide range of pH (4.0 to 9.0). In addition, PersiLipase1 demonstrated considerable tolerance toward metal ions and organic solvents (e.g., retaining >70% activity after the addition of 100 mM of chemicals). Hydrolysis of olive oil and sheep fat by this enzyme showed 100 % efficiency. Furthermore, the PersiLipase1 proved to be efficient for biotreatment of oil and grease from tannery wastewater with the hydrolysis efficiency of 90.76 % ± 0.88. These results demonstrated that the metagenome-derived PersiLipase1 from tannery wastewater has a promising potential for the biodegradation and management of oily wastewater pollution.

Sources, purification, immobilization and industrial applications of microbial lipases: An overview

Microbial lipase is looking for better attention with the fast growth of enzyme proficiency and other benefits like easy, cost-effective, and reliable manufacturing. Immobilized enzymes can be used repetitively and are incapable to catalyze the reactions in the system continuously. Hydrophobic supports are utilized to immobilize enzymes when the ionic strength is low. This approach allows for the immobilization, purification, stability, and hyperactivation of lipases in a single step. The diffusion of the substrate is more advantageous on hydrophobic supports than on hydrophilic supports in the carrier. These approaches are critical to the immobilization performance of the enzyme. For enzyme immobilization, synthesis provides a higher pH value as well as greater heat stability. Using a mixture of immobilization methods, the binding force between enzymes and the support rises, reducing enzyme leakage. Lipase adsorption produces interfacial activation when it is immobilized on hydrophobic support. As a result, in the immobilization process, this procedure is primarily used for a variety of industrial applications. Microbial sources, immobilization techniques, and industrial applications in the fields of food, flavor, detergent, paper and pulp, pharmaceuticals, biodiesel, derivatives of esters and amino groups, agrochemicals, biosensor applications, cosmetics, perfumery, and bioremediation are all discussed in this review.

A new bioremediation method for removal of wastewater containing oils with high oleic acid composition: Acinetobacter haemolyticus lipase immobilized on eggshell membrane with improved stabilities

As a result of the increasing demand for edible oils, which are an important part of human nutrition, in recent years, serious environmental problems may arise both during the production and after consumption of these oils.

Enzyme-Coated Micro-Crystals: An Almost Forgotten but Very Simple and Elegant Immobilization Strategy

The immobilization of enzymes using protein coated micro-crystals (PCMCs) was reported for the first time in 2001 by Kreiner and coworkers. The strategy is very simple. First, an enzyme solution must be prepared in a concentrated solution of one compound (salt, sugar, amino acid) very soluble in water and poorly soluble in a water-soluble solvent. Then, the enzyme solution is added dropwise to the water soluble solvent under rapid stirring. The components accompanying the enzyme are called the crystal growing agents, the solvent being the dehydrating agent. This strategy permits the rapid dehydration of the enzyme solution drops, resulting in a crystallization of the crystal formation agent, and the enzyme is deposited on this crystal surface. The reaction medium where these biocatalysts can be used is marked by the solubility of the PCMC components, and usually these biocatalysts may be employed in water soluble organic solvents with a maximum of 20% water. The evolution of these PCMC was to chemically crosslink them and further improve their stabilities. Moreover, the PCMC strategy has been used to coimmobilize enzymes or enzymes and cofactors. The immobilization may permit the use of buffers as crystal growth agents, enabling control of the reaction pH in the enzyme environments. Usually, the PCMC biocatalysts are very stable and more active than other biocatalysts of the same enzyme. However, this simple (at least at laboratory scale) immobilization strategy is underutilized even when the publications using it systematically presented a better performance of them in organic solvents than that of many other immobilized biocatalysts. In fact, many possibilities and studies using this technique are lacking. This review tried to outline the possibilities of this useful immobilization strategy.

A Novel Fungal Lipase With Methanol Tolerance and Preference for Macaw Palm Oil

Macaw palm is a highly oil-producing plant, which presents high contents of free fatty acids, being a promising feedstock for biofuel production. The current chemical routes are costly and complex, involving highly harsh industrial conditions. Enzymatic processing is a potential alternative; however, it is hampered by the scarce knowledge on biocatalysts adapted to this acidic feedstock. This work describes a novel lipase isolated from the thermophilic fungus Rasamsonia emersonii (ReLip), which tolerates extreme conditions such as the presence of methanol, high temperatures, and acidic medium. Among the tested feedstocks, the enzyme showed the highest preference for macaw palm oil, producing a hydrolyzate with a final free fatty acid content of 92%. Crystallographic studies revealed a closed conformation of the helical amphipathic lid that typically undergoes conformational changes in a mechanism of interfacial activation. Such conformation of the lid is stabilized by a salt bridge, not observed in other structurally characterized homologs, which is likely involved in the tolerance to organic solvents. Moreover, the lack of conservation of the aromatic cluster IxxWxxxxxF in the lid of ReLip with the natural mutation of the phenylalanine by an alanine might be correlated with the preference of short acyl chains, although preserving catalytic activity on insoluble substrates. In addition, the presence of five acidic amino acids in the lid of ReLip, a rare property reported in other lipases, may have contributed to its ability to tolerate and be effective in acidic environments. Therefore, our work describes a new fungal biocatalyst capable of efficiently hydrolyzing macaw oil, an attractive feedstock for the production of "drop-in" biofuels, with high desirable feature for industrial conditions such as thermal and methanol tolerance, and optimum acidic pH. Moreover, the crystallographic structure was elucidated, providing a structural basis for the enzyme substrate preference and tolerance to organic solvents.

Comparative Structural Analysis of Different Mycobacteriophage-Derived Mycolylarabinogalactan Esterases (Lysin B)

Mycobacteriophage endolysins have emerged as a potential alternative to the current antimycobacterial agents. This study focuses on mycolylarabinogalactan hydrolase (LysB) enzymes of the α/β-hydrolase family, which disrupt the unique mycolic acid layer of mycobacterium cell wall. Multiple sequence alignment and structural analysis studies showed LysB-D29, the only enzyme with a solved three-dimensional structure, to share several common features with esterases (lacking lid domain) and lipases (acting on long chain lipids). Sequence and structural comparisons of 30 LysB homology models showed great variation in domain organizations and total protein length with major differences in the loop-5 motif harboring the catalytic histidine residue. Docking of different p-nitrophenyl ligands (C4-C18) to LysB-3D models revealed that the differences in length and residues of loop-5 contributed towards wide diversity of active site conformations (long tunnels, deep and superficial funnels, shallow bowls, and a narrow buried cave) resembling that of lipases, cutinases, and esterases. A set of seven LysB enzymes were recombinantly produced; their activity against p-nitrophenyl esters could be related to their active site conformation and acyl binding site. LysB-D29 (long tunnel) showed the highest activity with long chain p-nitrophenyl palmitate followed by LysB-Omega (shallow bowl) and LysB-Saal (deep funnel).

Low-cost mussel inspired poly(Catechol/Polyamine) modified magnetic nanoparticles as a versatile platform for enhanced activity of immobilized enzyme

Owing to dopamine's excellent adhesion ability and easy modification, it has been widely applied for enzyme immobilization, while the high cost of dopamine and low activity recovery of immobilized enzyme highly impede large-scale application of immobilized enzyme. We herein developed a low-cost and ideal activity recovery enzyme immobilization strategy based on magnetic nanoparticles by replacing dopamine with cheap Catechol/tetraethylene pentamine (CPA) binary system and introducing spacer-arms. In brief, CPA was first polymerized and deposited on the surface of magnetic nanoparticles with a modified mussel-inspired method, and the generated poly(CPA) layer was further functionalized with ethylene glycol diglycidyl ether (EGDE) molecules as spacer-arms for enzyme immobilization. Subsequently, lipases as model enzymes were firmly immobilized on the surface of such amino-epoxy functionalized magnetic materials through ion exchange and covalent attachment with 180.6 mg/g support of loading capacity and 69.2% of activity recovery under the optimized conditions. Furthermore, the immobilized lipase exhibited the improved tolerance rang of pH, temperature and storage stability as well as excellent reusability. Most strikingly, the theoretical simulation and secondary structure analysis of immobilized lipase revealed that the biocompatible microenvironment and flexible tethering at interface could effectively improve performance of the immobilized enzyme and stability. Thus, this novel immobilized enzyme strategy will open up a new perspective for the development of enzyme immobilization and lower the cost of immobilized enzyme in large-scale industrial application.

Immobilization on octyl-agarose beads and some catalytic features of commercial preparations of lipase a from Candida antarctica (Novocor ADL): Comparison with immobilized lipase B from Candida antarctica

Lipase A from Candida antarctica (CALA, commercialized as Novocor ADL) was immobilized on octyl-agarose, which is a very useful support for lipase immobilization, and coated with polyethylenimine to improve the stability. The performance was compared to that of the form B of the enzyme (CALB) immobilized on the same support, as both enzymes are among the most popular ones used in biocatalysis. CALA immobilization produced a significant increase in enzyme activity vs. p-nitrophenyl butyrate (pNPB) (by a factor of seven), and the coating with PEI did not have a significant effect on enzyme activity. CALB reduced its activity slightly after enzyme immobilization. Octyl-CALA was less stable than octyl-CALB at pH 9 and more stable at pH 5 and, more clearly, at pH 7. PEI coating only increased octyl-CALA stability at pH 9. In organic solvents, CALB had much better stability in methanol and was similarly stable in acetonitrile or dioxane. In these systems, the PEI coating of octyl-CALA permitted some stabilization. While octyl-CALA was more active vs. pNPB, octyl-CALB was much more active vs. mandelic esters or triacetin. Thus, depending on the specific reaction and the conditions, CALA or CALB may offer different advantages and drawbacks. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2735, 2019.

High-level expression and characterization of a stereoselective lipase from Aspergillus oryzae in Pichia pastoris

Pichia pastoris expression is a mature and efficient eukaryotic expression system. In this work, Aspergillus oryzae lipase (AOL, with the molecular mass of 28 kDa), which can perform highly stereoselective hydrolysis of (R, S)-methyl 2-(4-hydroxyphenoxy) propanoate, was expressed in P. pastoris X-33. The specific activity of AOL was 432 U/mg, which was obtained by fed-batch cultivation in a 5 L bioreactor using a methanol feeding strategy. After fermentation, the supernatant was concentrated by ultrafiltration with a 10 kDa cut-off membrane and purified with DEAE-Sepharose™ FF ion-exchange chromatography and phenyl Seflnose™ 6 FF hydrophobic interaction chromatography. The purified lipase activity reached 5509 U/mg. AOL showed high activity toward short-chain triacylglyceride (C₄), and the optimum temperature and pH were 40 °C and 8.0, respectively. The purified enzyme activity was inhibited by Zn²⁺ and Cu²⁺. Moreover, the K_m and V_max values were 1 mM and 32.89 mmol/min, respectively.

The Lid Domain in Lipases: Structural and Functional Determinant of Enzymatic Properties

Lipases are important industrial enzymes. Most of the lipases operate at lipid–water interfaces enabled by a mobile lid domain located over the active site. Lid protects the active site and hence responsible for catalytic activity. In pure aqueous media, the lid is predominantly closed, whereas in the presence of a hydrophobic layer, it is partially opened. Hence, the lid controls the enzyme activity. In the present review, we have classified lipases into different groups based on the structure of lid domains. It has been observed that thermostable lipases contain larger lid domains with two or more helices, whereas mesophilic lipases tend to have smaller lids in the form of a loop or a helix. Recent developments in lipase engineering addressing the lid regions are critically reviewed here. After on, the dramatic changes in substrate selectivity, activity, and thermostability have been reported. Furthermore, improved computational models can now rationalize these observations by relating it to the mobility of the lid domain. In this contribution, we summarized and critically evaluated the most recent developments in experimental and computational research on lipase lids.

Molecular mechanism of activation of Burkholderia cepacia lipase at aqueous–organic interfaces

Structure and thermodynamics of lipase activation at aqueous–organic interfaces.

Process optimization for production and purification of a thermostable, organic solvent tolerant lipase from Acinetobacter sp. AU07

The purpose of this study was to isolate, purify and optimize the production conditions of an organic solvent tolerant and thermostable lipase from Acinetobacter sp. AU07 isolated from distillery waste. The lipase production was optimized by response surface methodology, and a maximum production of 14.5 U/mL was observed at 30 °C and pH 7, using a 0.5% (v/v) inoculum, 2% (v/v) castor oil (inducer), and agitation 150 rpm. The optimized conditions from the shake flask experiments were validated in a 3 L lab scale bioreactor, and the lipase production increased to 48 U/mL. The enzyme was purified by ammonium sulfate precipitation and ion exchange chromatography and the overall yield was 36%. SDS-PAGE indicated a molecular weight of 45 kDa for the purified protein, and Matrix assisted laser desorption/ionization time of flight analysis of the purified lipase showed sequence similarity with GDSL family of lipases. The optimum temperature and pH for activity of the enzyme was found to be 50 °C and 8.0, respectively. The lipase was completely inhibited by phenylmethylsulfonyl fluoride but minimal inhibition was observed when incubated with ethylenediaminetetraacetic acid and dithiothreitol. The enzyme was stable in the presence of non-polar hydrophobic solvents. Detergents like SDS inhibited enzyme activity; however, there was minimal loss of enzyme activity when incubated with hydrogen peroxide, Tween 80 and Triton X-100. The kinetic constants (K_m and V_max) revealed that the hydrolytic activity of the lipase was specific to moderate chain fatty acid esters. The V_max, K_m and V_max/K_m ratio of the enzyme were 16.98 U/mg, 0.51 mM, and 33.29, respectively when 4-nitrophenyl palmitate was used as a substrate.

Enhanced production of Thermomyces lanuginosus lipase in Pichia pastoris via genetic and fermentation strategies

This study attempted to enhance the expression level of Thermomyces lanuginosus lipase (TLL) in Pichia pastoris using a series of strategies. The tll gene was first inserted into the expression vector pPIC9 K and transformed into P. pastoris strain GS115. The maximum hydrolytic activity of TLL reached 4,350 U/mL under the optimal culture conditions of a 500 mL shaking flask containing 20 mL culture medium with the addition of 1.2 % (w/v) methanol, cultivation for 144 h at pH 7.0 and 27 °C. To further increase the TLL expression and copy number, strains containing two plasmids were obtained by sequential electroporation into GS115/9k-TLL #3 with a second vector, either pGAPZαA-TLL, pFZα-TLL, or pPICZαA-TLL. The maximum activity of the resultant strains GS115/9KTLL-ZαATLL #40, GS115/9KTLL-FZαATLL #46 and GS115/9KTLL-GAPTLL #45 was 6,600 U/mL, 6,000 U/mL and 4,800 U/mL, respectively. The tll copy number in these strains, as assessed by real-time quantitative PCR, was demonstrated to be seven, five, and three, respectively, versus two copies in GS115/9k-TLL #3. When a co-feeding strategy of sorbitol/methanol was adopted in a 3-L fermenter, the maximum TLL activity of GS115/9k-TLL #3 increased to 27,000 U/mL after 130 h of fed-batch fermentation, whereas, the maximum TLL activity was 19,500 U/mL after 145 h incubation when methanol was used as the sole carbon source.

Enzymatic enrichment of polyunsaturated fatty acids using novel lipase preparations modified by combination of immobilization and fish oil treatment

Novel modification methods for lipase biocatalysts effective in hydrolysis of fish oil for enrichment of polyunsaturated fatty acids (PUFAs) were described. Based on conventional immobilization in single aqueous medium, immobilization of lipase in two phase medium composed of buffer and octane was employed. Furthermore, immobilization (in single aqueous or in two phase medium) coupled to fish oil treatment was integrated. Among these, lipase immobilized in two phase medium coupled to fish oil treatment (IMLAOF) had advantages over other modified lipases in initial reaction rate and hydrolysis degree. The hydrolysis degree increased from 12% with the free lipase to 40% with IMLAOF. Strong polar and hydrophobic solvents had negative impact on immobilization-fish oil treatment lipases, while low polar solvents were helpful to maintain the modification effect of immobilization-fish oil treatment. After five cycles of usage, the immobilization-fish oil treatment lipases still maintained more than 80% of relative hydrolysis degree.

P450cam biocatalysis in surfactant-stabilized two-phase emulsions

Cytochrome P450 monooxygenases (P450s) are powerful biocatalysts that have the ability to oxidize a broad range of substrates, often at non-reactive carbon centers. However, incorporation of P450s into synthetic schemes has so far been limited to a few whole-cell transformations. P450 substrates are often hydrophobic and have low water solubility, limiting the amount of product that can be produced. To help overcome this limitation, we have examined P450cam activity in two-phase hexane/water emulsions with and without the anionic surfactant, bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT). Hydroxylation of camphor to hydroxycamphor by the three- component P450cam system was chosen as the model reaction, and regeneration of NADH was accomplished with yeast alcohol dehydrogenase (YADH). P450cam was activated in the surfactant-free emulsions, and addition of AOT improved the activity even further, at least over the range of camphor concentrations for which initial rates were readily measurable in all media. The largest observed rate enhancement was 4.5-fold. Nearly 50-times more product was formed in the surfactant-stabilized emulsions than was achieved in aqueous buffer, with total turnover numbers reaching 28,900 for P450cam and 11,800 for YADH. In the absence of surfactant, the two-phase reaction appeared to be mass-transfer limited, while inclusion of AOT alleviated transport limitations and/or afforded a larger interfacial area for P450 activation. The oxidation of hydroxycamphor to 2,5-diketocamphane was also observed, owing to the large concentration of hydroxycamphor relative to camphor in the aqueous phase of the two-phase emulsion. This competing reaction was accompanied by the uncoupled oxidation of NADH (i.e., NADH oxidation without formation of 2,5-diketocamphane), which reduced the availability of NADH for camphor oxidation and further limited the yield of hydroxycamphor in the two-phase emulsions. These results indicate that a surfactant-stabilized two-phase emulsion is a promising reaction medium for practical P450 biocatalysis, although its effectiveness for a given P450/substrate combination can depend on several factors, including competitive or sequential reactions, product inhibition, and NAD(P)H uncoupling.

Amperometric biosensor based on Prussian Blue-modified screen-printed electrode for lipase activity and triacylglycerol determination

Lipase activity against triacylglycerols has been measured using an amperometric enzyme biosensor based on glycerol dehydrogenase/NADH oxidase. A Prussian Blue modified screen-printed electrode was selected as substrate for the two immobilised-enzyme systems due to their higher operative stability reported in previous works. Various parameters such as cofactor (flavin mononucleotide FMN) concentration (1 mM), NAD+ coenzyme concentration (2 mM), pH effect (phosphate buffer pH 6 to 8, Tris buffer pH 8-10) response time and storage stability were evaluated and optimised. The glycerol biosensor was then investigated for lipase activity. The system was challenged against an olive or sunflower oil real samples in order to detect fatty acids and the results were compared with those provided either by the manufacture or reference methods with good agreement.

A Supported Liquid Membrane Encapsulating a Surfactant-Lipase Complex for the Selective Separation of Organic Acids

We have developed a novel, lipase-facilitated, supported liquid membrane (SLM) for the selective separation of organic acids by encapsulating a surfactant-lipase complex in the liquid membrane phase. This system exhibited a high transport efficiency for 3-phenoxypropionic acid and enabled the selective separation of organic acids due to the different solubilities of the acids in the organic phase and the variable substrate specificity of the surfactant-lipase complex in the liquid membrane phase. We found that various parameters, such as the amount of surfactant-lipase complex in the SLM, the lipase concentration in the receiving phase, and the ethanol concentration in the feed phase, affected the transport behavior of organic acids. The optimum conditions were 5 g L(-1) of the surfactant-CRL complex in the SLM (CRL=lipase from Candida rugosa), 8 g L(-1) of PPL in the receiving phase (PPL=lipase from porcine pancreas), and an ethanol concentration of 50 vol %. Furthermore, we achieved high enantioselective transport of (S)-ibuprofen attributable to the enantioselectivity of the surfactant-CRL complex.

Highly Enantioselective Separation Using a Supported Liquid Membrane Encapsulating Surfactant−Enzyme Complex

We developed a highly enantioselective separation system for the optically active compounds, (S)-ibuprofen and l-phenylalanine, from their racemic mixtures by employing a supported liquid membrane (SLM) encapsulating a surfactant-lipase complex (or a surfactant-alpha-chymotrypsin complex). In the present system, enzymes encapsulated in the liquid-membrane phase effectively drove the enantioselective transport of optically active compounds through the SLM. This novel SLM allowed high enantioselectivity (ee over 91%) in the optical resolution of racemic ibuprofen and phenylalanine.

Transport of organic acids through a supported liquid membrane driven by lipase-catalyzed reactions

We have developed a lipase-facilitated supported liquid membrane. Lipase-catalyzed reactions were coupled with a supported liquid membrane (SLM) to transport organic acids through the SLM. We succeeded in the rational transport of organic acids through the SLM using lipase-catalyzed reactions and observed that there were differences in the transport behavior of various organic acids due to the substrate specificity of lipase. Subsequently, various parameters, such as the alcohol concentration in the feed phase, the pH in each aqueous phase, an organic solvent in the SLM, and the kind of lipase, were investigated. We found that the optimum conditions were 65 vol% alcohol concentration, pH 6.3 in each aqueous phase, isooctane as the liquid membrane phase and Candida rugosa lipase as the esterification biocatalyst.