Catalytic Behaviour of Lipase Free and Immobilized in Biphasic Membrane Reactor with Different Low Water-Soluble Substrates

The catalytic activity and reaction rate of lipase have been studied using the biocatalyst free in an organic/aqueous emulsion and immobilized in a biphasic organic/aqueous membrane reactor. The first reaction system was realized in a stirred tank reactor. The other was obtained by immobilizing the enzyme in the sponge layer of an asymmetric capillary membrane and recirculating the two phases along the two separate circuits of the membrane module. The performance of the reactors has been studied using two different low water-soluble substrates: triglycerides present in commercial olive oil and (R,S)-cyanomethyl-[2-(4-isobutylphenyl)propionate] (CNE). The effects of substrate viscosity and flow dynamics conditions, such as organic phase flow rate, on the biphasic membrane reactor performance have been evaluated on the basis of observed reaction rate and catalytic activity of free and immobilized lipase for both substrates. It has been observed that free lipase showed higher catalytic activity with olive oil, while immobilized lipase showed higher catalytic activity with CNE which has a lower viscosity than olive oil. The increase of organic phase flow rate negatively affected the reactor performance, with a minor effect when using CNE rather than olive oil. The influence of temperature on the biocatalyst performance with the two substrates has also been investigated. The optimal temperature value of lipase was different for the two substrates: 28°C with CNE and 40°C with olive oil. © 1997 SCI.     

Aspergillus oryzae Lipase-Catalyzed Synthesis of Dioleoyl; Palmitoyl-Rich Triacylglycerols in Two Reactors

Dioleoyl; palmitoyl‐rich triacylglycerols (OPO‐rich TAG) were synthesized through Aspergillus oryzae lipase (AOL)‐catalyzed acidolysis of palm stearin with commercial oleic acid by a one‐step process in a stirred tank reactor and continuous packed bed reactor to evaluate the feasibility of using immobilized AOL. AOL was found to be valuable for the synthesis of OPO‐rich TAG when compared with commercial lipase from Thermomyces lanuginose (Lipozyme^® TL IM; Novozymes A/S, Bagsvaerd, Denmark). The C52 (triglycerides with a carbon number of 52, stands for OPO, OPL, LPL and their isomers) content of AOL was higher (45.65 %), and the intensity of treatment (IOT: lipase amount × reaction time/TAG amount) of AOL was just 6.25 % of that of Lipozyme^® TL IM under similar reaction conditions in the stirred tank reactor. Response surface methodology were used to optimize the reaction conditions of the AOL‐catalyzed acidolysis is reaction in the packed bed reactor. The optimal point for the set of experimental conditions generated were as follows: residence time 3.0 h; temperature 62.09 °C; substrate molar ratio 7.13 mol/mol. The highest C52 content obtained was 48.60 ± 2.36 %, with 57.46 ± 1.72 % total palmitic acid at the sn‐2 position and 74.21 ± 2.45 % oleic acid at the sn‐1,3 positions. The half‐life of AOL was 24 h in the stirred tank reactor and 140 h in the packed bed reactor. The immobilized AOL achieved similar conversion and selectivity to commercial lipases for the catalyzed synthesis of OPO‐rich TAG and may offer a cheaper alternative.     

Study on the enzymatic hydrolysis of racemic methyl ibuprofen ester

The hydrolysis of racemic methyl ibuprofen ester in the presence of lipase from Candida rugosa was investigated in shake flasks. Experiments were performed to study the effect of temperature, pH and shaking speed on the reaction rate. Different hydrophobic co‐solvents were screened for the highest reaction rate and the presence of enzyme inhibition by substrate and products was examined. A kinetic expression was then proposed to describe the reaction. Kinetic parameters were determined for the optimum operating conditions and the proposed model was verified with the experimental results. Next, this reaction was scaled up to a fed batch stirred tank reactor. Batch reactor and fed batch reactor configurations were compared for better conversions. The effects of aqueous phase hold‐up, substrate concentration and feed flow rate on the conversion of the reaction were also studied. Higher conversions were obtained in a fed batch reactor when compared with the batch reactor. In the fed batch reactor, increased conversions were observed with lower feed flowrates and high aqueous phase hold‐up. © 2001 Society of Chemical Industry     

反应器操作方式对酶动力学拆分立体选择性的影响

描述了在批式反应器和连续流搅拌反应器（ＣＳＴＲ）中酶动力学拆分对映异构体的不同之处，从宏观反应器平衡角度，推导出了在ＣＳＴＲ反应器中不同于在批式反应器中的一定酶立体选择性（Ｅ）下，底物或产物的对映体过量值与反应的转化率之间关系的定量关系式。并通过商品脂肪酶及芽胞杆菌Ｅ－５３脂肪酶催化的萘普生甲酯的不对称水解反应得到了证实。分别在批式反应器和ＣＳＴＲ反应器中进行萘普生的酶法拆分，在一定转化率下，批式     

Regioselective lipase‐catalyzed synthesis of glucose ester on a preparative scale

Glucose fatty acid monoesters were produced in a stirred‐tank reactor in combination with a membrane‐pervaporation separation unit for the regeneration of the solvent ethyl methylketone (EMK) on a preparative scale. Yields up to 79% (169 g product) were achieved in the synthesis of 6‐O‐stearoyl‐D‐glucose in a mainly solid phase system in the presence of a small amount of EMK maintaining a catalytic liquid phase as well as forming a suitable azeotropic mixture with the reaction water. High residual activity was found using lipase B from Candida antarctica under reduced pressure at 60 °C. EMK could be easily removed from the reaction mixture and is regarded as biocompatible in the preparation of food additives.     

Lipase‐catalyzed dynamic kinetic resolution of (R,S)‐fenoprofen thioester in isooctane

A lipase‐catalyzed enantioselective hydrolysis process under in situ racemization of the remaining (R)‐thioetser substrate with trioctylamine as the catalyst was developed for the production of (S)‐fenoprofen from (R,S)‐fenoprofen 2,2,2‐trifluoroethyl thioester in isooctane. Detailed investigations of trioctylamine concentration on the enzyme activation and the kinetic behavior of the thioester in racemization and enzymatic reactions were conducted, in which good agreement between the experimental data and theoretical results was observed. © 2002 Society of Chemical Industry     

Two‐phase production of cyclohexene and cyclooctene oxides in water as an approach to pollution prevention

Liquid–liquid two‐phase epoxidation from cyclohexene and cyclooctene in aqueous potassium peroxymonosulfate (commercially available as Oxone^®) solution was studied as an application in pollution prevention. To avoid potential emissions of volatile organic compounds an aqueous solution was employed to replace the usual chlorinated solvents used in epoxide production. A droplet column reactor and stirred tank reactor were used to investigate two‐phase synthesis of epoxide. An aqueous Oxone^® solution was used to oxidize a dispersion of alkene droplets and form epoxide. The study of aqueous epoxidation in both reactors showed that the epoxidation of alkenes can be represented as a first order reaction with respect to alkene. The salting out effect of Oxone^® concentration was studied in both reactors and found to be very similar at optimal conditions. In comparing the two reactors, it was found that the droplet column reactor produces larger quantities of product per unit reactor volume for the same reaction time. The objective of this study is to provide an alternative reactor design and synthesis route that can meet pollution prevention goals. Copyright © 2004 Society of Chemical Industry     

Effect of mass transfer on biodesulfurization kinetics of alkylated forms of dibenzothiophene by Pseudomonas putida CECT5279

BACKGROUND: An important problem exists for the implementation of biodesulfurization technology of fuels related to the influence of mass transfer on the overall reaction rate and process yield. Pseudomonas putida CECT5279 has been shown to be one of the most promising biocatalysts, but most kinetic studies were done at small scale and their capability for the transformation of alkyl substituted forms (Cx–DBTs) has not yet been reported. RESULTS: Conversion yields and kinetic parameters were calculated under aqueous and biphasic resting cell conditions in a 2 L stirred tank reactor. In aqueous reaction media, 100% conversion of DBT, 4MDBT and 4,6DMDBT was achieved while the conversions in the presence of an organic liquid were 38% for DBT, 19.5% for 4MDBT and 16.5% for 4,6DMDBT, showing that the process is strongly affected by mass transfer between liquids. Laboratory scale–up of P. putida CECT5279 growing step was successfully carried out using a 15 L stirred tank, on the basis of the volumetric mass transfer coefficient (k_La). CONCLUSIONS: P. putida CECT5279 is capable of removing Cx–DBT compounds successfully in aqueous resting cell conditions using stirred tank reactors, but in biphasic media, mass transfer between liquids controls the process, increasing time of reaction and lowering process yield. © 2012 Society of Chemical Industry     

The effect of organic loading rate on the anaerobic digestion of two‐phase olive mill solid residue derived from fruits with low ripening index

A study of the effect of organic loading rate on the performance of anaerobic digestion of two‐phase olive mill solid residue (OMSR) was carried out in a laboratory‐scale completely stirred tank reactor. The reactor was operated at an influent substrate concentration of 162 g chemical oxygen demand (COD) dm^?3. The organic loading rate (OLR) varied between 0.8 and 11.0 g COD dm^?3 d^?1. COD removal efficiency decreased from 97.0% to 82.6% when the OLR increased from 0.8 to 8.3 g COD dm^?3 d^?1. It was found that OLRs higher than 9.2 g COD dm^?3 d^?1 favoured process failure, decreasing pH, COD removal efficiency and methane production rates (Q_M). Empirical equations described the effect of OLR on the process stability and the effect of soluble organic matter concentration on the total volatile fatty acids (TVFA)/total alkalinity (TAlk) ratio (ρ). The results obtained demonstrated that rates of substrate uptake were correlated with concentration of biodegradable COD, through an equation of the Michaelis–Menten type. The kinetic equation obtained was used to simulate the anaerobic digestion process of this residue and to obtain the theoretical COD degradation rates in the reactor. The small deviations obtained (equal to or lower than 10%) between values calculated through the model and experimental values suggest that the proposed model predicts the behaviour of the reactor accurately. Copyright © 2007 Society of Chemical Industry     

Effect of co‐solvent addition on the reaction kinetics of the lipase‐catalyzed resolution of ibuprofen ester

BACKGROUND: The addition of co‐solvent is not limited to enhancing the catalytic rate, it could also assist in situ racemization in the dynamic kinetic resolution of racemic compounds by increasing the reactivity of the base catalyst employed. In the current work, reaction media with the presence of DMSO were investigated in Candida rugosa lipase (EC 3.1.1.3)‐catalyzed hydrolysis of ibuprofen ester that focuses on the thermodynamic effect, reaction stability and implication for the kinetic parameters. RESULTS: The introduction of 2% DMSO increased the reaction rate, conversion, and enantioselectivity of the Candida rugosa lipase‐mediated resolution. However, the performance of the particular enzymatic reaction was reduced when a higher DMSO concentration was added. At lower reaction temperatures, the medium with 2% DMSO exhibited an increase in enantioselectivity, which was attributed to a higher activation energy difference between the fast‐ and slow‐reacting enantiomers compared with the water‐isooctane medium. Additionally, the presence of DMSO had a significant effect on the kinetic parameters, shown by a lower value of Michaelis constant compared with that of a normal reaction without DMSO, which resulted in a fast reaction rate. Finally, inhibition due to the uncompetitive substrate inhibitor was reduced, while the non‐competitive product inhibitor consequently increased. CONCLUSION: This work has demonstrated that only 2% of DMSO can be tolerated by the free Candida rugosa lipase in the resolution of ibuprofen ester. However, it is still able to give significant positive effects on the hydrolysis rate, kinetic parameters and enantioselectivity as well as reaction stability. © 2012 Society of Chemical Industry     

Comparison of lipase production by Geotrichum candidum in stirring and airlift fermenters

The production of lipase by Geotrichum candidum in both, stirred tank and airlift bioreactors were compared. G candidum an imperfect filamentous fungus, grows well in liquid medium, and produces a lipase with specific affinity for long‐chain fatty acids with cis‐9 double bonds but, lipase production is generally not efficient because the optimum medium composition and fermentation conditions are not known. Response surface methodology was used to optimize the agitation speed (100–500 rpm) and aeration (0.2–1.8 vvm) for production of lipase by G candidum in a bench‐scale stirred fermenter. A Central Composite Rotatable Design (CCRD) was used to optimize lipase activity and productivity. Lipase production in an airlift fermenter was also studied with aeration ranging from 1 to 3 vvm. A previously optimized culture medium containing 3.58% of peptone, 0.64% of soy oil and an initial pH of 7.0, was used in the experiments, incubating at 30°C. In the stirred reactor the optimum conditions of agitation and aeration for lipase production and productivity were 300 rpm and 1 vvm, leading to an activity of 20 U cm^?3 in 54 h of fermentation and 0.3900 (U cm^?3 h^?1) of productivity. The best aeration condition in the airlift fermenter was 2.5 vvm, which yielded similar lipase activity after 30 h of fermentation, resulting in a productivity of 0.6423 (U cm^?3 h^?1). In the absence of mechanical agitation similar lipase yields were achieved but in less time, resulting in productivity, about 60% greater than in a stirred fermenter; the lower energy demand for the same lipase yield offers economic advantages. Copyright © 2004 Society of Chemical Industry     

Einfluss der Reaktorkonfiguration auf die Enantioselektivität einer kinetischen Racematspaltung

The optical purity of a product at the reactor outlet depends not only on the enantioselectivity of the catalyst, but also on the reactor configuration. Different reactor configurations are compared with respect to the enantiomeric excess (ee) at a respective conversion that can be achieved in a kinetic resolution of a racemate. For batch, fed‐batch and plug flow reactors enantioselectivities (E value) of 35 are sufficient to achieve high enantiomeric excess. For a continuously operated stirred tank reactor high ee values are only obtained for E values higher than 190.     

Lipolytic enzyme production in batch and fed‐batch cultures of Ophiostoma piceae and Fusarium oxysporum

Lipase and esterase production by Ophiostoma piceae and Fusarium oxysporum were enhanced and extended by developing a fed‐batch process in stirred tank reactors. Fed‐batch strategy improved lipolytic enzyme production from Ophiostoma piceae in both 2 and 20 dm³ stirred tank reactors. However, fed‐batch fermentation of Fusarium oxysporum in the 2 dm³ reactor was more effective than both batch and fed‐batch fermentations in the 20 dm³ reactor. When a medium composed of only carbon and nitrogen source was intermittently fed to the cultures, the maximum specific lipase activity was improved by more than 80% and 35% in Ophiostoma piceae and Fusarium oxysporum cultures respectively. The maximum specific esterase activity was improved by 20% and 15% in Ophiostoma piceae and Fusarium oxysporum cultures respectively. The duration of production for both fungi extended from 144 to 216 h compared with a batch culture under the same condition. © 2000 Society of Chemical Industry     

Improving Aqueous Biphasic Hydroformylation of Unsaturated Oleochemicals Using a Jet‐Loop‐Reactor

In two case studies, the reaction performance of the aqueous biphasic hydroformylation of two industrially relevant oleochemicals, namely methyl 10‐undecenoate (case 1) and methyl oleate (case 2), is significantly improved by the use of a Jet‐Loop Reactor concept. Based on previously reported studies, only the two green and benign co‐solvents, 1‐butanol and isopropanol are applied, respectively, in the absence of any additional auxiliary. Both reactions benefit highly from using this special piece of equipment, specifically designed for improving gas–liquid–liquid mixing to create large interfacial areas with no moving internals. In case 1, the loading of the co‐solvent 1‐butanol is successfully reduced. For the first time significant yields (>40% after 1 h) are obtained in the absence of any co‐solvent, which is very beneficial, since aldehyde products and substrate form a pure product phase enabling straightforward separation. In case 2, the loading of the substrate methyl oleate is successfully increased from 6 to 30 wt% still showing satisfying productivity. At 15 wt%, the yield of the desired internal aldehydes in the jet‐loop reactor is increased by a factor of five compared to a stirred tank reactor after 3 h. Practical Applications: The production of aldehydes from hydroformylation of olefins is highly relevant for the chemical industry, since these can undergo numerous subsequent reactions, to form for instance alcohols, amines, and carboxylic acids. Generally, aldehydes from oleochemicals can serve as platform chemicals for gaining access to bifunctional molecules, which are interesting as polymer precursors. Performing hydroformylation with a water‐based solvent system enables efficient product separation from the aqueous catalyst phase for the realzation of more sustainable processes. By using the Jet‐Loop Reactor, the performance of the reaction system can be greatly improved addressing its practical relevance.     

Study of a continuous reactor for selective solvent extraction of haemorphins in the course of peptic haemoglobin hydrolysis

The continuous hydrolysis of bovine haemoglobin at pH 3 in a triphasic reactor was studied in order to prepare two pure transient and hydrophobic opioid peptides in one step. A continuous stirred‐tank reactor was designed to extract continuously and selectively LVV‐haemorphin‐7 and VV‐haemorphin‐7 by a butan‐2‐ol–octan‐1‐ol mixture in the course of bovine haemoglobin hydrolysis by pepsin immobilised on A568 Duolite resin. The residence time in the aqueous and organic phases was maintained at 1 h. This system allowed a steady state to be achieved for haemorphin concentrations in each phase and the pepsin stability to be maintained. Finally, success was achieved in producing and extracting continuously the two haemorphins in the aqueous/butan‐2‐ol–octan‐1‐ol biphasic medium for more than 10 bed volumes of the reactor. Copyright © 2006 Society of Chemical Industry     

Bioproduction of cis‐(1S,2R)‐indandiol,a chiral pharmaceutical intermediate,using a solid–liquid two‐phase partitioning bioreactor for enhanced removal of inhibitors

BACKGROUND: A solid‐liquid two‐phase partitioning bioreactor (TPPB) was used in the biotransformation of indene to cis‐(1S,2R)‐indandiol by Pseudomonas putida 421‐5 (ATCC 55687). Metered substrate feeding in single‐phase operation, or delivery from an immiscible liquid, have previously been employed to regulate the exposure of the biocatalyst to inhibitory concentrations of the substrate. In contrast, the solid‐liquid platform provided in situ substrate addition (ISSA) as well as simultaneous it in situ product removal (ISPR) as a means of overcoming substrate and product toxicity. Three different modes of operation were compared for their effects on the performance of this biotransformation: single‐phase, fed‐batch operation was carried out as a benchmark in 2.75 L aqueous medium, and subsequently with the inclusion of either 700 g liquid silicone oil or 700 g solid polymer beads. RESULTS: Biphasic modes achieved a 3‐fold productivity improvement with respect to single‐phase (30 to 90 mg L^?1 h^?1), and solid‐liquid productivity was similar to liquid‐liquid operation while achieving more extensive removal of inhibitory compounds resulting in a slightly higher product titer (1.29 vs 1.16 g L^?1). The operability of the reactor was improved by the phase stability of the solid polymer beads relative to immiscible organic solvents, preventing emulsion formation and facilitating analytics. CONCLUSION: Solid polymer beads replaced the immiscible liquid auxiliary phase for substrate delivery while performing simultaneous inhibitory molecule sequestration. Copyright © 2011 Society of Chemical Industry     

Preparation of sorbitol from D‐glucose hydrogenation in gas–liquid–solid three‐phase flow airlift loop reactor

A new process for D ‐glucose hydrogenation in 50 wt% aqueous solution, into sorbitol in a 1.5 m³ gas–liquid–solid three‐phase flow airlift loop reactor (ALR) over Raney Nickel catalysts has been developed. Five main factors affecting the reaction time and molar yield to sorbitol, including reaction temperature (T_R), reaction pressure (P_R), pH, hydrogen gas flowrate (Q_g) and content of active hydrogen, were investigated and optimized. The average reaction time and molar yield were 70 min and 98.6% under the optimum operating conditions, respectively. The efficiencies of preparation of sorbitol between the gas–liquid–solid three‐phase flow ALR and stirred tank reactor (STR) under the same operating conditions were compared. Copyright © 2004 Society of Chemical Industry     

Comparative Study of Sterol Ester Synthesis using <Emphasis Type="Italic">Thermomyces Lanuginosus</Emphasis> Lipase in Stirred Tank and Packed-Bed Bioreactors

A comparative study was done on the production of different sterol esters using a stirred tank batch reactor (STBR) and packed bed reactor (PBR) using Thermomyces lanuginosus (Lipozyme TLIM) enzyme, a commercially immobilized lipase. Different oils were used as the sources of particular fatty acids, e.g., fish oil for n-3 polyunsaturated fatty acids (n-3 PUFA), linseed oil for alpha linolenic acid (ALnA) and mustard oil for erucic acid. Reaction parameters, such as substrate molar ratio, reaction temperature and enzyme concentration, were standardized in the STBR and maintained in the PBR. To provide equal time of residence between the substrate and enzyme in both the reactors for the same amount of substrates, the substrate flow rate in the PBR was maintained at 0.27 ml/min. Thin layer chromatography was used to monitor the reaction, and column chromatography was used to determine the product yields. Fatty acid compositions of the esters were determined by gas chromatography. The study showed that the packed bed bioreactor was more efficient than the batch reactor in sterol-ester synthesis with less migration of acyl groups.     

Fe/Mn oxide decorated polyacrylonitrile hollow fiber membrane as heterogeneous Fenton reactor for methylene blue decolorization

A very distinctive modification route was schemed to fabricate a membrane reactor that could heterogeneously catalyze Fenton reactions to decolorize dye wastewater in the process of filtration. Through this route, porogen-free polyacrylonitrile (PAN) hollow fiber membrane was decorated with in situ generated well-distributed Fe/Mn composite oxide, and the so-called membrane reactor was finally acquired. Its performance of decolorizing dye wastewater was evaluated by feeding methylene blue (MB) aqueous solution into its lumen side and analyzing the permeate gained from its shell side. The results showed that about 97.4% of MB could be removed from its aqueous solution as the solution passed through the shell side of hollow fiber membrane, and this removal efficiency would keep unchanged when operation period was lengthened. The membrane reactor presented excellent capability to decolorize MB aqueous solution and could be used repeatedly without any loss in decolorization efficiency. Finally, the mechanism of causing MB decolorization was proposed by comparing decolorization performance of modified and unmodified membranes, measuring total organic carbon, and analyzing UV–Vis spectra. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48217.     

Parameter optimization for the enzymatic hydrolysis of sunflower oil in high-pressure reactors

This study is concerned with the hydrolysis of sunflower oil in the presence of lipase preparation Lipolase 100T (Aspergillus niger lipase). Supercritical carbon dioxide was used as a solvent for this reaction. In a high-pressure stirred tank reactor operated in a batch mode, the effects of various process parameters (temperature, pressure, enzyme/substrate ratio, pH, and oil/buffer ratio) were investigated to determine the optimal reaction rate and conversion for the hydrolysis process. The optimal concentration of lipase was 0.0714 g/mL of CO₂-free reaction mixture, and the highest conversions of oleic acid (0.193 g/g of oil phase) and linoleic acid (0.586 g/g of oil phase) were obtained at 50°C, 200 bar, pH=7, and an oil/buffer ratio of 1∶1 (w/w).