Enhanced Performance of Thermomyces lanuginosus Lipase-Catalyzed Regioselective Acylation of 6-Azauridine by a Co-Solvent Approach

2012 ◽  
Vol 550-553 ◽  
pp. 1395-1399
Author(s):  
Yan Hong Bi ◽  
Zhao Yu Wang ◽  
Xi Rong Zhao
Keyword(s):  
Reaction Medium ◽  
Solvent Mixture ◽  
Thermomyces Lanuginosus ◽  
Solvent Mixtures ◽  
Anhydrous Acetone ◽  
Lipozyme Tl Im ◽  
Regioselective Acylation ◽  
Substrate Conversion ◽  
Solvent Systems ◽  
Hydrophobic Solvent

A comparative study was made of lipozyme TL IM-catalyzed regioselective acylation of 6-azauridine with vinyl palmitate for the preparation of the 5'-O-monoester in co-solvent mixtures and pure polar solvents. Among the solvent systems investigated, a co-solvent mixture of anhydrous acetone/isooctane was found to be the best reaction medium, in which Lipozyme TL IM also exhibited good thermal and operational stability. It was also found that the acylation was dependent on the hydrophobic solvent content. The most suitable co-solvent was anhydrous acetone/isooctane (90:10, v/v). Under the optimal conditions, the initial rate, substrate conversion and 5'-regioselectivity were 20.6 mM/h, 99.0% and 99%, respectively.

Enzymatic synthesis of a chiral chalcogran intermediate

2014 ◽  
Vol 68 (6) ◽  
Author(s):  
Vladimír Mastihuba ◽  
Pavel Čepec ◽  
Silvia Vlčková ◽  
Erika Farkašová ◽  
Mária Mastihubová ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Bark Beetle ◽  
Enzymatic Synthesis ◽  
Kinetic Resolution ◽  
Thermomyces Lanuginosus ◽  
Methyl Tert Butyl Ether ◽  
Lipozyme Tl Im ◽  
Butyl Ether ◽  
Novozyme 435 ◽  
Reaction Media

AbstractTwo lipases, Novozyme 435 (lipase B from Candida Antarctica) and Lipozyme TL IM (Thermomyces lanuginosus) were used successfully for the kinetic resolution of racemic 1-(2-furyl)-3-pentanol, the key intermediate in synthesis of the bark beetle pheromone, chalcogran. The desired S-(+)-enantiomer was prepared in enantiomeric excesses higher than 98 % and with yields of 26.3 % and 32.5 %, respectively. Methyl tert-butyl ether and vinyl acetate were found to be the best reaction media and the acetyl donor to achieve fast and effective resolution.

Identifying thermal phase transitions of lignin–solvent mixtures using electrochemical impedance spectroscopy

2016 ◽  
Vol 18 (7) ◽  
pp. 1892-1897 ◽  
Author(s):  
Adam S. Klett ◽  
Jordan A. Gamble ◽  
Mark C. Thies ◽  
Mark E. Roberts
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Solvent Mixtures ◽  
New Approach ◽  
Thermal Phase ◽  
Solvent Systems ◽  
Thermal Phase Transitions

A new approach to measuring the phase-transition temperature of lignin–solvent systems using electrochemical impedance spectroscopy is reported.

scholarly journals Synthesis of Dietetic Structured Lipids from Spent Coffee Grounds Crude Oil Catalyzed by Commercial Immobilized Lipases and Immobilized Rhizopus oryzae Lipase on Biochar and Hybrid Support

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1542
Author(s):  
Danyelle A. Mota ◽  
Jefferson C. B. Santos ◽  
Diana Faria ◽  
Álvaro S. Lima ◽  
Laiza C. Krause ◽  
...  
Keyword(s):  
Crude Oil ◽  
Rhizopus Oryzae ◽  
Structured Lipids ◽  
Thermomyces Lanuginosus ◽  
Spent Coffee Grounds ◽  
Lipozyme Tl Im ◽  
Rhizopus Oryzae Lipase ◽  
Lipozyme Rm Im ◽  
Coffee Grounds ◽  
Pharmaceutical Industries

The aim of this study was the valorization of coffee industry residues, namely spent coffee grounds (SCG) as a source of oil, and silverskin (CS) as a source of both oil and biomass, under the concept of the circular economy. Therefore, crude oil from SCG was used to produce low-calorie structured lipids (SL) for food and pharmaceutical industries, and CS to produce biochar by pyrolysis for biotechnological uses. SL were obtained by acidolysis with caprylic or capric acid, or interesterification with ethyl caprylate or ethyl caprate, in solvent-free media, catalyzed by immobilized sn-1,3 regioselective lipases. Silverskin biochar (BIO) was directly used as enzyme carrier or to produce hybrid organic-silica (HB) supports for enzyme immobilization. Rhizopus oryzae lipase (ROL) immobilized on Amberlite (AMB), silica (SIL), BIO or HB, and the commercial immobilized Thermomyces lanuginosus (Lipozyme TL IM) and Rhizomucor miehei (Lipozyme RM IM) lipases were tested. Lipozyme RM IM showed better results in SL production than Lipozyme TLIM or ROL on BIO, SIL or HB. About 90% triacylglycerol conversion was attained after 7 h acidolysis or interesterification. Lipozyme RM IM was more stable in interesterification (80% and 65% activity with ethyl caprylate or ethyl caprate) than in acidolysis (first-order decay) after 10 reuses.

Aggregation studies of benzoporphyrin derivative

2001 ◽  
Vol 79 (5-6) ◽  
pp. 1068-1074 ◽  
Author(s):  
David Delmarre ◽  
Noboru Hioka ◽  
Ron Boch ◽  
Ethan Sternberg ◽  
David Dolphin
Keyword(s):  
Dielectric Constant ◽  
Photodynamic Therapy ◽  
Photophysical Properties ◽  
Equilibrium Constants ◽  
Solvent Mixtures ◽  
Ph Values ◽  
Beer's Law ◽  
Beer’S Law ◽  
Solvent Systems ◽  
Porphyrin Dimers

The photophysical properties of a ring B benzoporphyrin derivative 1,3-diene dimethylester were investigated in solution (water–DMSO mixtures). At low proportions of water in DMSO, the diester obeys Beer's law at all pH values and ionic strengths investigated. For solvent systems containing more than 30% water, the extent of deviation from Beer's law as a function of porphyrin concentration is attributed to formation of porphyrin dimers. Dimerization equilibrium constants (Kd) have been determined in different percentage of solvent mixtures, using absorption and fluorescence spectroscopies, and were found to exhibit a linear correlation between log (Kd) and the inverse of the dielectric constant (log (Kd) = 24.6 – 1060.4 × 1/εmix). This equation permits the calculation of Kd in mixtures of water–DMSO.Key words: porphyrins, dimerization, aggregation, fluorescence, benzoporphyrin derivative, photodynamic therapy, photosensitizers.

scholarly journals Study of Soybean Oil Hydrolysis Catalyzed by Thermomyces lanuginosus Lipase and Its Application to Biodiesel Production via Hydroesterification

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Elisa d'Avila Cavalcanti-Oliveira ◽  
Priscila Rufino da Silva ◽  
Alessandra Peçanha Ramos ◽  
Donato Alexandre Gomes Aranda ◽  
Denise Maria Guimarães Freire
Keyword(s):  
Soybean Oil ◽  
Methyl Esters ◽  
Reaction Medium ◽  
Acid Catalyst ◽  
Biodiesel Production ◽  
Thermomyces Lanuginosus ◽  
Molar Ratio ◽  
Esterification Reaction ◽  
Thermomyces Lanuginosus Lipase ◽  
Niobic Acid

The process of biodiesel production by the hydroesterification route that is proposed here involves a first step consisting of triacylglyceride hydrolysis catalyzed by lipase from Thermomyces lanuginosus (TL 100L) to generate free fatty acids (FFAs). This step is followed by esterification of the FFAs with alcohol, catalyzed by niobic acid in pellets or without a catalyst. The best result for the enzyme-catalyzed hydrolysis was obtained under reaction conditions of 50% (v/v) soybean oil and 2.3% (v/v) lipase (25 U/mL of reaction medium) in distilled water and at 60∘C; an 89% conversion rate to FFAs was obtained after 48 hours of reaction. For the esterification reaction, the best result was with an FFA/methanol molar ratio of 1:3, niobic acid catalyst at a concentration of 20% (w/w FFA), and 200∘C, which yielded 92% conversion of FFAs to soy methyl esters after 1 hour of reaction. This study is exceptional because both the hydrolysis and the esterification use a simple reaction medium with high substrate concentrations.

scholarly journals Synthesis of tetraalkyl thiuram disulfides using different oxidants in recycling solvent mixture

2012 ◽  
Vol 18 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Milutin Milosavljevic ◽  
Aleksandar Marinkovic ◽  
Jelena Markovic ◽  
Danijela Brkovic ◽  
Milan Milosavljevic
Keyword(s):  
Isopropyl Alcohol ◽  
Level Structure ◽  
Reaction Medium ◽  
Solvent Mixture ◽  
Azeotropic Mixture ◽  
Water Mixture ◽  
Alcohol Water ◽  
High Yields ◽  
Industrial Level ◽  
Laboratory Synthesis

A new optimized laboratory synthesis of tetraalkyl thiuram disulfides, starting from dialkyl amines and carbon disulfide in presence of three oxidants (hydrogen peroxide, potassium peroxodisulfate and sodium hypochlorite) and appropriate reaction medium: two mixtures of isopropyl alcohol - water used in two consecutive syntheses, was presented in this work. First synthesis was performed in a recycled azeotropic mixture of isopropyl alcohol - water 87.7% - 12.3%, and second in a filtrate obtained after first synthesis, which was a mixture of isopropyl alcohol - water 70.4% - 29.6%. After the second synthesis and filtration, recycled azeotropic mixture isopropyl alcohol - water 87.7% - 12.3% was regenerated from the filtrate by rectification. Considering this, the technology for beneficial use of recycling isopropyl alcohol - water mixture as reaction medium for tetraalkyl thiuram disulfides synthesis was developed. Such concept contributes to extraordinary economical benefit of implemented optimal laboratory synthesis at semi-industrial level. High yields of tetraalkyl thiuram disulfides syntheses were obtained at both laboratory and semiindustrial level. Structure and purity of synthesized compounds were confirmed by elemental analysis, as well as FTIR, 1H and 13C NMR, and MS spectral data.

scholarly journals Fast real-time monitoring of entacapone crystallization and characterization of polymorphs via Raman spectroscopy, statistics and SWAXS

2014 ◽  
Vol 64 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Tomislav Jednačak ◽  
Aden Hodzic ◽  
Otto Scheibelhofer ◽  
Marijan Marijan ◽  
Johannes G. Khinast ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Optical Probe ◽  
Solvent Mixture ◽  
Binary Solvent ◽  
Solvent Mixtures ◽  
Starting Point ◽  
Principal Components Method ◽  
Components Method

Abstract Crystallization of the drug entacapone from binary solvent mixtures was monitored in situ using a Raman optical probe. The recorded Raman spectra and statistical analysis, which included the principal components method and indirect hard modeling made it possible to estimate the starting point of crystallization, to assess crystallization temperatures and to provide information on the polymorphic content of the mixture. It was established that crystallization temperatures were proportional to the volume content of the solvent in mixtures. The samples were also evaluated off-line via Raman spectroscopy and SWAXS. The collected data showed the presence of forms b and g in all solvent mixtures. In a toluene/methanol 30:70 mixture, in addition to forms b and g, at least one of the forms A, D or a was also indicated by SWAXS. The results have shown that the presence of a particular polymorph is strongly dependent on the nature and portion of the solvent in the binary solvent mixture.

scholarly journals Solvent Mixture Optimization in the Extraction of Bioactive Compounds and Antioxidant Activities from Garlic (Allium sativum L.)

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6026
Author(s):  
Vytória Piscitelli Cavalcanti ◽  
Smail Aazza ◽  
Suzan Kelly Vilela Bertolucci ◽  
João Pedro Miranda Rocha ◽  
Adriane Duarte Coelho ◽  
...  
Keyword(s):  
Binary Mixture ◽  
Bioactive Compounds ◽  
Antioxidant Activities ◽  
Pure Water ◽  
Extraction Procedure ◽  
Solvent Mixture ◽  
Total Phenolic ◽  
Solvent Mixtures ◽  
Garlic Powder ◽  
Dpph Scavenging

Garlic is a health promoter that has important bioactive compounds. The bioactive extraction is an important step in the analysis of constituents present in plant preparations. The purpose of this study is to optimize the extraction with the best proportion of solvents to obtain total phenolic compounds (TPC) and thiosulfinates (TS) from dried garlic powder, and evaluate the antioxidant activities of the optimized extracts. A statistical mixture simplex axial design was used to evaluate the effect of solvents (water, ethanol, and acetone), as well as mixtures of these solvents, after two ultrasound extraction cycles of 15 min. Results showed that solvent mixtures with a high portion of water and pure water were efficient for TPC and TS recovery through this extraction procedure. According to the regression model computed, the most significant solvent mixtures to obtain high TPC and TS recovery from dried garlic powder are, respectively, the binary mixture with 75% water and 25% acetone and pure water. These optimized extracts presented oxygen radical absorbance capacity. Pure water was better for total antioxidant capacity, and the binary mixture of water–acetone (75:25) was better for DPPH scavenging activity. These optimized extracts can be used for industrial and research applications.

scholarly journals Thermodynamic Studies of Complexes of Amlodipine Besylate with Ni2+, Mg2+, Co2+ and Ca2+ cations in pure and in mixed binary solvent systems at 303.15, 313.15 and 323.15 K by Conductometric Method

2020 ◽  
Vol 13 (1) ◽  
pp. 206-216
Author(s):  
Dhruvi. R. Mehta ◽  
Raviprakash S. Chandra ◽  
M. M. Maisuria
Keyword(s):  
Driving Force ◽  
Binary Solvent ◽  
Complexation Reaction ◽  
Solvent Mixtures ◽  
Amlodipine Besylate ◽  
Linear Change ◽  
Conductometric Method ◽  
Binary Solvent Systems ◽  
Solvent Systems ◽  
The Stability

The present work relates to the complexation reaction between Amlodipine Besylate[AML] with Ni2+, Mg2+, Co2+ and Ca2+ cation in dimethylsulfoxide (DMSO), pure methanol (MeOH) and their binary mixtures(DMSO-MeOH and DMSO-Water) by conductometric method. The conductance data show that the stoichiometry of the complexes formed between AML with Ni2+, Mg2+, Co2+ and Ca2+ cation in pure DMSO, pure MeOHas well as in the binary solvent mixtures was 1:1. The stability of AML complexes with Ni2+ , Mg2+, Co2+ and Ca2+ metal ion was observed to be sensitive to the nature of the solvent system. In case of DMSO-Water binary solvent systems there was a linear change in LogKf values but in case of DMSO-MeOH binary solvent systems non linear change in LogKf values observed.The negative values of ΔG0 show that the reaction is spontaneous and ability of the AML ligand to form stable complexes. However, the result shows positive value of ΔH0 which indicates that enthalpy is not driving force for the formation of the complexes. Furthermore, the positive value of ΔS0 indicates that entropy is a driving force for the complexation. The values of ΔH0 and ΔS0 for formation of the complexes were obtained from temperature dependence of the stability constants.

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