Enantioselective synthesis of (S)-ibuprofen ester prodrug in cyclohexane by Candida rugosa lipase immobilized on Accurel MP1000

Acoustic Characterization and Modeling of Silicone-Bonded Cocoa Crop Waste Using a Model Based on the Gaussian Support Vector Machine

The sustainable management of waste from agricultural crops represents an urgent challenge. One possible solution considers waste as possible secondary raw materials for specific uses. Among these, the use of agricultural waste as a product for the assembly of panels for the sound absorption of living environments represents a particularly suitable solution. In this study, the acoustic properties of the cocoa pod husk were evaluated, using silicone as a binder. Different proportions of materials and thicknesses were evaluated. A Support Vector Machine (SVM)-based model with a Gaussian kernel was then used to predict the acoustic performance of composite materials. The results obtained suggest the adoption of this material for the acoustic correction of living environments and this methodology for the prediction of the acoustic behavior of materials.

Biocatalytic Approach for Direct Esterification of Ibuprofen with Sorbitol in Biphasic Media

Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) introduced in the 1960s and widely used as an analgesic, anti-inflammatory, and antipyretic. In its acid form, the solubility of 21 mg/L greatly limits its bioavailability. Since the bioavailability of a drug product plays a critical role in the design of oral administration dosage, this study investigated the enzymatic esterification of ibuprofen as a strategy for hydrophilization. This work proposes an enzymatic strategy for the covalent attack of highly hydrophilic molecules using acidic functions of commercially available bioactive compounds. The poorly water-soluble drug ibuprofen was esterified in a hexane/water biphasic system by direct esterification with sorbitol using the cheap biocatalyst porcine pancreas lipase (PPL), which demonstrated itself to be a suitable enzyme for the effective production of the IBU-sorbitol ester. This work reports the optimization of the esterification reaction.

Immobilization of Candida rugosa lipase for resolution of racimic ibuprofen

AIM

Due to lipases' regio-selectivity and ability to catalyze different reactions such as hydrolysis, esterification, and transesterification, the enzyme is attractive in biotransformation technology. Besides, another technology, namely enzyme immobilization, has attracted scientists/technologists' attention to employ immobilized lipase in such a field. Thus lipase of Candida rugosa was immobilized onto silica nanoparticles through adsorption. Furthermore, the immobilized biocatalyst was characterized and used to esterify ibuprofen enantioselectively.

METHODS

To characterize immobilized lipase onto silica nanoparticles scanning electron microscopy (SEM) and dynamic light scattering (DLS) were used.

RESULTS

The catalytic properties of both immobilized and free lipases such as optima pH and temperature were not different. According to the results, the immobilized lipase on silica nanoparticles showed 45% and 96% conversion (C) and enantioselectivity (ee_s), respectively. In comparison to free lipase, the immobilized enzyme came with better catalytic activity.

CONCLUSION

Silica nanoparticles as one of the most promising materials for the immobilization of lipase in enantioselective esterification of ibuprofen, were introduced in this work.

Covalent Immobilization of Candida rugosa Lipase on Epichlorohydrin-Coated Magnetite Nanoparticles: Enantioselective Hydrolysis Studies of Some Racemic Esters and HPLC Analysis

In this study, a new biocatalyst was prepared by immobilizing Candida rugosa lipase epichlorohydrin-functionalized onto the surface of the nanoparticles. Magnetite nanoparticles were obtained by chemical co-precipitation method of Fe²⁺ and Fe³⁺, and then the prepared uncoated and coated nanoparticles were characterized by XRD, FT-IR and TGA. Lipase was covalently attached to activated nanoparticles. The catalytic properties of free and immobilized lipases were determined. It was found that the optimum temperature for free and immobilized lipases was 30 °C and 35 °C, respectively. The optimum pH values were found to be 7.0 and 8 for free and immobilized lipases, respectively. Immobilized lipase was found to retain significant activity even after the seventh use. In the final section of the study, optically pure compounds were obtained by carrying out the enantioselective hydrolysis studies of racemic esters by using immobilized lipase. Enantiomeric excesses of the products in the enantioselective hydrolysis of racemic ibuprofen and naproxen methyl ester and racemic butyl mandelate were determined to be 94.93, 77.30 and 68.15, respectively.

Overcoming Water Insolubility in Flow: Enantioselective Hydrolysis of Naproxen Ester

Hydrolytic enantioselective cleavage of different racemic non-steroidal anti-inflammatory drugs (NSAIDs) ester derivatives has been studied. An engineered esterase form Bacillus subtilis (BS2m) significantly outperformed homologous enzymes from Halomonas elongata (HeE) and Bacillus coagulants (BCE) in the enantioselective hydrolysis of naproxen esters. Structural analysis of the three active sites highlighted key differences which explained the substrate preference. Immobilization of a chimeric BS2m-T4 lysozyme fusion (BS2mT4L1) was improved by resin screening achieving twice the recovered activity (22.1 ± 5 U/g) with respect to what had been previously reported, and was utilized in a packed bed reactor. Continuous hydrolysis of α-methyl benzene acetic acid butyl ester as a model substrate was easily achieved, albeit at low concentration (1 mM). However, the high degree of insolubility of the naproxen butyl ester resulted in a slurry which could not be efficiently bioconverted, despite the addition of co-solvents and lower substrate concentration (1 mM). Addition of Triton® X-100 to the substrate mix yielded 24% molar conversion and 80% e.e. at a 5 mM scale with 5 min residence time and sufficient retention of catalytic efficiency after 6 h of use.

Harnessing Marine Biocatalytic Reservoirs for Green Chemistry Applications through Metagenomic Technologies

In a demanding commercial world, large-scale chemical processes have been widely utilised to satisfy consumer related needs. Chemical industries are key to promoting economic growth and meeting the requirements of a sustainable industrialised society. The market need for diverse commodities produced by the chemical industry is rapidly expanding globally. Accompanying this demand is an increased threat to the environment and to human health, due to waste produced by increased industrial production. This increased demand has underscored the necessity to increase reaction efficiencies, in order to reduce costs and increase profits. The discovery of novel biocatalysts is a key method aimed at combating these difficulties. Metagenomic technology, as a tool for uncovering novel biocatalysts, has great potential and applicability and has already delivered many successful achievements. In this review we discuss, recent developments and achievements in the field of biocatalysis. We highlight how green chemistry principles through the application of biocatalysis, can be successfully promoted and implemented in various industrial sectors. In addition, we demonstrate how two novel lipases/esterases were mined from the marine environment by metagenomic analysis. Collectively these improvements can result in increased efficiency, decreased energy consumption, reduced waste and cost savings for the chemical industry.

Cocoa pod husk, a new source of hydrolase enzymes for preparation of cross-linked enzyme aggregate

Cocoa pod husk (CPH) is a by-product of cocoa production obtained after removing the beans from the fruit. The analysis of CPH has shown that it contains high amounts of protein. This study is aimed to utilize this protein source in hydrolase enzyme production. In this study, seven hydrolase enzymes (amylase, fructosyltransferase, mannanase, glucosidase, glucanase, lipase and protease) were screened from CPH for the first time for feasible industrial production. Among these hydrolases, lipase was chosen for the next steps of experiments as it has a lot of applications in different industries. The extraction of high active lipase from CPH has been done under optimum conditions. The condition that was optimum for the three major factors was achieved using Face centered central composite design (FCCCD) with response surface methodology (RSM) to obtain the highest enzyme activity of crude lipase from CPH. The optimum condition of extraction is used for preparation of cross-linked enzyme aggregate (CLEA). For the production of immobilized biocatalyst, the technique of CLEA is considered as an effective technique for its industrially attractive advantages. Referring to the results of OFAT, CLEA-lipase was prepared in the best condition at the presence of 30 mM ammonium sulphate, 70 mM glutaraldehyde with 0.23 mM Bovine serum albumin as an additive. Immobilization effectively improved the stability of lipase against various organic solvents.

Enzymatic synthesis of ibuprofen monoglycerides catalyzed by free Candida antarctica lipase B in a toluene–glycerol biphasic medium

Reactive distillation in the presence of toluene permits the intensification of ibuprofen monoglyceride synthesis by means of aCandida antarcticaindustrial solution, attaining total conversion.

Enantioselective behavior of lipases from Aspergillus niger immobilized in different supports

Considering the extraordinary microbial diversity and importance of fungi as enzyme producers, the search for new biocatalysts with special characteristics and possible applications in biocatalysis is of great interest. Here, we report the performance in the resolution of racemic ibuprofen of a native enantioselective lipase from Aspergillus niger, free and immobilized in five types of support (Accurel EP-100, Amberlite MB-1, Celite, Montmorillonite K10 and Silica gel). Amberlite MB-1 was found to be the best support, with a conversion of 38.2%, enantiomeric excess of 50.7% and enantiomeric ratio (E value) of 19 in 72 h of reaction. After a thorough optimization of several parameters, the E value of the immobilized Aspergillus niger lipase was increased (E = 23) in a shorter reaction period (48 h) at 35 degrees C. Moreover, the immobilized Aspergillus niger lipase maintained an esterification activity of at least 80% after 8 months of storage at 4 degrees C and could be reused at least six times.

Immobilization of lipases on hydrophobilized zirconia nanoparticles: highly enantioselective and reusable biocatalysts

Our study has demonstrated for the first time that zirconia nanoparticles modified by a simple carboxylic surfactant of a very long alkyl chain can significantly enhance the activity of the immobilized lipases for asymmetric synthesis in organic media. Zirconia nanoparticles of ca. 20 nm diameter were grafted with carboxylic surfactant modifiers from Tween 85 and erucic acid. The surface of nanoparticles was successfully changed from hydrophilic to hydrophobic. Lipases from Candida rugosa and Pseudomonas cepacia were immobilized on the modified zirconia nanoparticles by adsorption in aqueous solution. The immobilized lipases were used for the resolution of ( R, S)-ibuprofen and ( R, S)-1-phenylethanol through esterification and acylation, respectively, in isooctane organic solvent. When immobilized on erucic acid-modified zirconia, both lipases gave significantly higher activity and enantioselectivity compared with those from their corresponding crude lipase powders. The nanohybrid biocatalysts are stable and can be reused for eight cycles without loss in activity and selectivity. The interaction between the hydrophobic surface of zirconia support and lipases probably induces the conformational rearrangement of lipases into an active, stable form.

Sequential parametric optimization of lipase production by a mutant strain Rhizopus sp. BTNT-2

Lipase production by the mutant strain Rhizopus sp. BTNT-2 was optimized in submerged fermentation. Different chemical and physical parameters such as carbon sources, nitrogen sources, oils, inoculum level, pH, incubation time, incubation temperature and aeration have been extensively studied to increase lipase productivity. Potato starch (1.25% w/v) as a carbon source, corn steep liquor (1.5% w/v) as a nitrogen source and olive oil (0.5% v/v) as lipid source were found to be optimal for lipase production. The optimal levels of other parameters are 4 ml of inoculum (2.6x10(8) spores/ml), initial pH of 5.5, incubation time of 48 hours, incubation temperature of 28 degrees C and aeration rate of 120 rpm. With the optimized parameters, the highest production of lipase was 59.2 U/ml while an yield of only 28.7 U/ml was obtained before optimization resulting in 206% increase in the productivity.

Partially purifiedCarica papayalipase: a versatile biocatalyst for the hydrolytic resolution of (R,S)-2-arylpropionic thioesters in water-saturated organic solvents

With the hydrolytic resolution of (R,S)-naproxen 2,2,2-trifluoroethyl thioesters in water-saturated isooctane as a model system, improvements of the specific lipase activity and thermal stability were found when a crude Carica papaya lipase (CPL) was partially purified and employed as the biocatalyst. The partially purified Carica papaya lipase (PCPL) was furthermore explored as an effective enantioselective biocatalyst for the hydrolytic resolution of (R,S)-profen thioesters in water-saturated organic solvents. The kinetic analysis in water-saturated isooctane indicated that both acyl donor and acyl acceptor have profound influences on the lipase activity, E-value, and enantioselectivity. Inversion of the enantioselectivity from (S)- to (R)-thioester was found for (R,S)-fenoprofen and (R,S)-ketoprofen thioesters that contained a bulky substituent at the meta-position of 2-phenyl moiety of the acyl part. Kinetic constants for the acylation step were furthermore estimated for elucidating the kinetic data and postulating an active site model. The thermodynamic analysis indicated that the enantiomer discrimination was driven by the difference of activation enthalpy (DeltaDeltaH) and that of activation entropy (DeltaDeltaS), yet the latter was dominated for most of the reacting systems. The postulated active site model was supported from the variation of DeltaDeltaH and DeltaDeltaS with the acyl moiety, in which a good linear enthalpy-entropy compensation relationship was also illustrated. A comparison of the performances between Candida rugosa lipase (CRL) and PCPL indicated that PCPL was superior to CRL in terms of the better thermal stability, similar or better lipase activity for the fast-reacting substrate, time-course-stability, and lower enzyme cost.

Production, purification, characterization, and applications of lipases

Lipases (triacylglycerol acylhydrolases, EC 3.1.1.3) catalyze the hydrolysis and the synthesis of esters formed from glycerol and long-chain fatty acids. Lipases occur widely in nature, but only microbial lipases are commercially significant. The many applications of lipases include speciality organic syntheses, hydrolysis of fats and oils, modification of fats, flavor enhancement in food processing, resolution of racemic mixtures, and chemical analyses. This article discusses the production, recovery, and use of microbial lipases. Issues of enzyme kinetics, thermostability, and bioactivity are addressed. Production of recombinant lipases is detailed. Immobilized preparations of lipases are discussed. In view of the increasing understanding of lipases and their many applications in high-value syntheses and as bulk enzymes, these enzymes are having an increasing impact on bioprocessing.