Reduction and separation of nitrate and nitrite by liquid membrane‐encapsulated enzymes

Mohan, Raam R.; Li, Norman N.

doi:10.1002/bit.260160407

Cited by 54 publications

(13 citation statements)

References 17 publications

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“…Procedures have been developed to isolate proteins or enzymes in small spherical domains (capsules) surrounded by an artificial polymer membrane (1,6,7). The membrane is permeable to small substrate and product molecules but not to the larger protein molecules which are held within.…”

mentioning

confidence: 99%

Microencapsulation of Chloroplast Particles

Kitajima

Butler²

1976

Plant Physiol.

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Chloroplast and photosystem I particles were encapsulated in small spheres (about 20 gLm diameter) with an artificial membrane built up by cross-linking amino groups of protamine with toluenediisocyanate. The artificial membrane was permeable to small substrate and product molecules but not to soluble proteins. Photosystem I activity was retained by the encapsulated chloroplast particles. Washed photosystem I particles were encapsulated with the soluble proteins, ferredoxin, and ferredoxin-NADP oxidoreductase, and the mncrocapsules photoreduced NADP using ascorbate plus dichlorophenoHindophenol as the electron donor. The photosystem I particles were also encapsulated with hydrogenase from Chromatium and a very low rate of photoevolutioh of hydrogen was obtained. The MATERIALS AND METHODSChloroplasts and PSI3 particles were prepared by methods described by Sane et al. (8).Hydrogenase was prepared from Chromatium vinosum, strain D. Fifty g of cells were suspended in 150 ml of 0.1 M tris buffer, pH 8, containing 3% deoxycholate and 1% cholate and disrupted by a French press at 6,000 p.s.i. The supernatant from a 10,000g centrifugation for 30 min was collected and ammonium sulfate was added to 20% saturation. The precipitated proteins were discarded after another 10,000g centrifugation for 30 min and 1 ml of 0.5 M MnCl2 was added to the supernatant. The supernatant was heated to 63 C for 10 min, cooled on ice, and centrifuged again at 10,000g for 30 min. Solid ammonium sulfate was added to this latter supernatant to 60% saturation and precipitated proteins were collected by a centrifugation at 10,000g for 30 min. The pelleted proteins were dissolved in 50 ml of the tris buffer and stored until use in liquid N2.Microencapsulation of Chloroplasts. In the encapsulation procedures reported here, the material to be encapsulated was added to a dilute solution of gelatin which was a gel during the encapsulation procedures near 0 C but was a solution at room temperature where activity measurements were carried out. One ml of 10% gelatin (isoelectric point pH 9.2) was added to 4 ml of a 40% solution of protamine which had been adjusted to pH 8 with HCI. This mixture was warmed to give a clear solution and recooled at room temperature. Five ml of a chloroplast suspension of about 1 mg Chl/ml in a buffer of 20 mm KCI, 15 mm tris-HCI, pH 7.8, were stirred into the protamine-gelatin solution. One hundred ml of dibutylphthalate, DBP, were placed in a 200-ml stainless steel beaker in a H20 bath. The contents of the beaker were stirred with a fairly powerful, variable speed stirring unit with a stirring blade whose leading edge had been sharpened to increase shear. The chloroplast-protamine-gelatin mixture was added to the DBP while stirring (at room temperature), and the size of the droplets in the emulsion was adjusted by controlling the speed of the stirring motor. Ice was then added to the H20 bath, and the emulsion was cooled to about 5 C. After 10 min of stirring, to establish a stable emulsion, 5 ml of toluene-dii...

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confidence: 99%

Microencapsulation of Chloroplast Particles

Kitajima

Butler²

1976

Plant Physiol.

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“…While the initial work with liquid emulsion membranes involved chemical systems, the first biomedical application was demonstrated with the use of liquid emulsion membranes for drug delivery and drug overdose prevention systems (42). In the biochemical field, an early study describes a liquid emulsion membrane-encapsulated bacterial cell-free homogenate able to carry out the reduction of nitrate and nitrite (43). Since this early study in 1974, many other biochemical applications have been reported which describe more complex enzyme/liquid emulsion membrane systems.…”

Section: Liquid Membranesmentioning

confidence: 99%

Modeling and Applications of Downstream Processing

Hamel

Hunter

1990

ACS Symposium Series

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Downstream processing is playing an increasingly important role in the biochemical industry, especially since the advent of recombinant DNA technology. The use of recombinant DNA technology not only enables improvements in the production efficiency of therapeutic and industrial proteins, but it also permits the modification and improvement of protein structure and thus function.However, the commercial application of such technology was initially accompanied by concerns over product safety.Quality criteria have been made especially stringent for products derived from genetically-modified microorganisms. The establishment of strict quality guidelines was the result of early concern about the oncogenic potential related to products contaminated by DNA sequences of the host mammalian cells (1). The quest for high quality has created a growing need for high-resolution techniques at the process scale as well as for novel strategies for the isolation and purification of bioproducts. Since the typical environment for producing biologicals is a complex one and quality criteria need to be strict, primary recovery techniques are typically implemented in a purification scheme prior to (or in conjunction with) high-resolution techniques. The most sophisticated and useful schemes take advantage of both the different physical and chemical properties of the components in complex mixtures and of the interactive nature of the downstream processing techniques (see Figure 1).

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“…Cahn and Li (1974). May andLi (1972,1974), Mohan andLi (1974,1975), Matulevicius and Li (1975) and Kitagawa et al (1977). The membrane (oil) phase was 1% by weight Span 80.3% ENJ 3029, and 96% S100N.…”

Section: Liquid Membrane Emulsion Preparationmentioning

confidence: 99%

“…as effective tools for an increasingly wide variety of separations (Maugh, 1976). These include: 1. the fractionation of hydrocarbons (Li, 1971a(Li, , 1971bShah and Owens, 1972;Li, 1976a, 1976b;Alessi et al, 1980;Halwachs et al, 1980); 2. the recovery and enrichment of heavy metal ions (Schiffer et a]., 1974;Hochhauser and Cussler, 1975;Martin andDavies, 1976/1977;Kondo et al, 1979;Volkel et al, 1980;Strzelbicki and Charewicz, 1980; Since their discovery just over a decade ago (Li, 1968), liquid surfactant membranes have demonstrated considerable potential Frankenfeld et al, 1981); 3. the removal of trace contaminants from waste water (Li and Shrier, 1972;Cahn and Li, 1974;Frankenfeld and Li, 1977;Kitagawa et al, 1977;Halwachs et al, 1980;Terry et al, 1981); and 4. a number of diverse applications in the biochemical and biomedical fields (May and Li, 1972;Li andAsher, 1973, May andMohan andLi, 1974,1975;Asher et al, 1975Asher et al, , 1977May and Li, 1977;Frankenfeld et al, 1978). Liquid membranes also have potential utility as membrane reactors incorporating simultaneous separation and reaction processes (Ollis r t al., 1972;Wolynic and Ollis, 1974;Cussler and Evans, 1980).…”

Section: Introductionmentioning

confidence: 99%

Batch extraction with liquid surfactant membranes: A diffusion controlled model

et al. 1982

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A model of diffusion controlled mass transfer in liquid surfactant membranes is developed for uniform emulsion globules having no internal circulation. The solute is assumed to react instantaneously and irreversibly with the internal reagent a t a reaction surface which advances into the globule as the reagent is consumed. A perturbation solution to the resulting non-linear equations is presented. In general, the zero-order, or pseudo-steady state solution alone often gives an adequate representation of the process. Experimental data on the batch extraction of phenol from waste water are in good agreement with the model predictions.

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Reduction and separation of nitrate and nitrite by liquid membrane‐encapsulated enzymes

Cited by 54 publications

References 17 publications

Microencapsulation of Chloroplast Particles

Microencapsulation of Chloroplast Particles

Modeling and Applications of Downstream Processing

Batch extraction with liquid surfactant membranes: A diffusion controlled model

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