Analysis of a direct contact membrane reactor for lipase catalysed oil hydrolysis in a dynamic emulsion system (original) (raw)
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Journal of Fermentation and Bioengineering, 1995
Hydrolysis of olive oil in isooctane by lipase from Candida cylindracea in an aqueous solution was carried out in a polydispersed emulsion system prepared by a homogenizer and in a monodispersed emulsion system prepared by the shirasu-porous-glass (SPG) membrane emulsification method. An emulsion system consisting of both SDS and PVA at pH 7.8 was best suited for the reaction. In the monodispersed emulsion, the droplet diameter was controlled by the pore diameter of the SPG membrane to give droplets with a narrow diameter distribution range. The rate of hydrolysis was at&ted by the concentrations of olive oil and lipase, the interfacial area and the emulsion droplets diameter. The kinetic data were interpreted by the interfacial reaction model, in which desorption of the product from the interface was the rate determining step. The equilibrium constant of the adsorption of lipase at the interface were very small compared with that obtained in the isothermal adsorption equilibrium of lipase at the interface without a surfactant. The equilibrium constants of the reaction between lipase adsorbed at the interface and olive oil in the organic phase were nearly of the same order as those obtained in the Lewis cell and the VibroMixer. The desorption rate constants of the product were very large compared with that in the Lewis cell.
Journal of Fermentation and Bioengineering, 1995
Hydrolysis of olive oil in isooctane by lipase from Candida cylindracea in an aqueous solution was carried out in a polydispersed emulsion system prepared by a homogenizer and in a monodispersed emulsion system prepared by the shirasu-porous-glass (SPG) membrane emulsification method. An emulsion system consisting of both SDS and PVA at pH 7.8 was best suited for the reaction. In the monodispersed emulsion, the droplet diameter was controlled by the pore diameter of the SPG membrane to give droplets with a narrow diameter distribution range. The rate of hydrolysis was at&ted by the concentrations of olive oil and lipase, the interfacial area and the emulsion droplets diameter. The kinetic data were interpreted by the interfacial reaction model, in which desorption of the product from the interface was the rate determining step. The equilibrium constant of the adsorption of lipase at the interface were very small compared with that obtained in the isothermal adsorption equilibrium of lipase at the interface without a surfactant. The equilibrium constants of the reaction between lipase adsorbed at the interface and olive oil in the organic phase were nearly of the same order as those obtained in the Lewis cell and the VibroMixer. The desorption rate constants of the product were very large compared with that in the Lewis cell.
Process Biochemistry, 2004
Lipase from Candida rugosa was immobilized on Cuprophane membrane in a hollow-fibre module for possible application for oil hydrolysis. A simple immobilization technique was applied and 154.8 mg m −2 lipase was immobilized with approximately 40% mass yield. The reactor operating regime was investigated with respect to flow patterns in reactor zones, lipase desorption and hydrolysis rates. Flow pattern studies in the experimental system revealed nearly plug flow with a stagnant region in the reactor lumen and significant flow channeling in the shell zone. Mass transfer limitations were apparent in the lumen zone at flow rates below 15 cm 3 min −1 . Higher flow rates up to 50 cm 3 min −1 in the lumen zone and in the range 2.5-26 cm 3 min −1 in the shell side had no apparent influence on hydrolysis rates. At the enzyme load employed in this study, loss of enzyme activity due to desorption had little effect on reactor stability and oil hydrolysis. of substrate and/or products in a single unit, reuse of the enzyme, and continuous operation of the process.
Membranes
Multiphase bioreactors using interfacial biocatalysts are unique tools in life sciences such as pharmaceutical and biotechnology. In such systems, the formation of microdroplets promotes the mass transfer of reagents between two different phases, and the reaction occurs at the liquid–liquid interface. Membrane emulsification is a technique with unique properties in terms of precise manufacturing of emulsion droplets in mild operative conditions suitable to preserve the stability of bioactive labile components. In the present work, membrane emulsification technology was used for the production of a microstructured emulsion bioreactor using lipase as a catalyst and as a surfactant at the same time. An emulsion bioreaction system was also prepared by the stirring method. The kinetic resolution of (S,R)-naproxen methyl ester catalyzed by the lipase from Candida rugosa to obtain (S)-naproxen acid was used as a model reaction. The catalytic performance of the enzyme in the emulsion system...
Biomass and Bioenergy, 2012
Enzymatic membrane bioreactors (MBR) have been studied for very different applications since many years. Submerged MBR has also been successfully used for treatment of wastewater. In the existing submerged configuration, the membrane works as the separation unit operation while the bioconversion is carried out by microorganisms suspended in the tank reactor. In the present work, a novel approach that combines the concept of biocatalytic membranes and submerged modules is proposed for the treatment of biomass. Lipase enzyme from Candida rugosa has been immobilized in polyethersulphone hollow fiber (PES HF) membrane in order to develop a two separate phase biocatalytic submerged membrane reactor in which the membrane works as both catalytic and separation unit. Furthermore, the submerged biocatalytic membrane reactor is intended for production of valuable components from waste biomass, and different physical, chemical and fluid dynamics has been optimized. Response surface methodology (RSM) has been used to model the operating parameters and Box-Behnken method has been applied to maximize the fatty acids production and optimization. At TMP 80 AE 2 kPa, pH 7.40 AE 0.1, temperature 35 AE 0.5 C with an axial velocity of 0.07 AE 0.01 ms À1 and organic stirring 89.01 rad s À1 the system showed the global examined value within the experimental scope. The proof of principle using fried cooked oils has been performed in later period.
Chemical Engineering Journal, 1999
The effects of various water-in-oil (W/O) emulsion preparation variables, such as water-to-oil volume ratio of W/O emulsion, emulsi®cation speed and time, and emulsifying agent concentration, on the permeation rates of L-phenylalanine methyl ester (L-PME, substrate) and L-phenylalanine (L-Phe, product) were investigated in an enzyme±emulsion±liquid±membrane (EELM) system accompanying the hydrolysis of the substrate into the product. The permeation rate of the substrate was higher in the system with a higher water-to-oil volume ratio or lower emulsi®cation energy, while emulsifying agent concentration had little in¯uence on its permeation rate as far as emulsion was stable. The permeation rate of the product was highest in the system with water-to-oil ratio of 1/1, the lowest emulsi®cation energy or 7 wt.% emulsifying agent concentration. This is because the rate was dependent only on the mass transfer resistance, such as surfactant layer resistance at interfaces, membrane thickness, and the mass transfer area between external phase and emulsion drops. The explanation was supported by the experimentally measured data of emulsion drop size, emulsion viscosity, and internal droplet size. Finally, the optimum permeation rate was obtained at 7 wt.% emulsifying agent concentration, water-to-oil volume ratio of 1/1 and emulsi®cation speed of 6000 rpm for 15 min. #
Journal of Membrane Science, 2010
The aim of the present work was to develop and proof the concept of an integrated and intensified membrane system able to carry out in a single operation unit, bioconversion (in water phase), and simultaneous separation of reaction products (having different solubility and stability in water), by creating water in oil emulsion. To achieve this aim, the concepts of biocatalytic membrane reactor and membrane emulsification have been integrated. This resulted in a combined membrane operation system where hydrolysis occurred within the microporous membrane structure (that contained immobilized enzyme) and extraction occurred at the membrane interface. Here, the permeating water reaction phase was collected as droplets into the organic phase circulated along the lumen membrane surface. The oleuropein hydrolysis into glucose and isomer of oleuropein aglycon (3,4-DHPEA-EA) by means of -glucosidase immobilized in porous polymeric membrane has been used as a model reaction system.
New Biotechnology, 2014
Enzymatic biodiesel production kinetics under previously optimized conditions were investigated. Waste frying oil (WFO) was used as the raw material, Novozym 435 as catalyst, methanol as acyl acceptor and tert-butanol as co-solvent. To investigate pure transesterification kinetics improving product properties, 3 Å molecular sieves were incorporated into the reaction to provide an anhydrous medium avoiding the side reactions of hydrolysis and esterification. The effects of either WFO or methanol on the reaction rate were analyzed separately. The reaction was described by a Ping Pong mechanism and competitive inhibition by methanol. The results obtained in the kinetics study were applied in the operation of a semi-continuous reactor for biodiesel production. The operational conditions of each reaction cycle were: methanol-to-oil ratio 8/1 (mol/mol), 15% (wt) Novozym 435, 0.75% (v/v) of tertbutanol, 44.58C, 200 rpm and 4 h of reaction time. The enzymes were successively reused by remaining in the reactor during all the cycles. Under these conditions, biodiesel production yields higher than 80% over 7 reaction cycles were observed. Both the kinetics study and the reactor operation showed that Novozym 435 was not inhibited at high methanol concentrations and that the kinetics of the proposed enzymatic process could be comparable to the conventional chemical process.