Calcium—algin reaction

Reaction with periodate-oxidized agarose that had been treated with 1,6-diaminohexane and reduced Reaction with activated forms of silk Reaction with, and glutaraldehyde-linked to, various derivatives of controlled-porosity glass Entrapment in gels of calcium alginate Reaction with agarose cyclic imidocarbonate... 

Corynebacterium glutamicum (CGMCC No. 1464) cells immobilized in calcium alginate beads cross-linked with polyethenimine and glutaraldehyde have been employed for the production of nicotinamide from 3-cyanopyridine [21], The reaction was mn at 10-15 °C,... 

A collective anaerobic and aerobic treatment by immobilized microorganisms was first shown [66, 67] using calcium-alginate-immobilized co-cultures of a facultative anaerobic strain of Enterobacter cloacae. Reaction actually took place in the middle of the alginate beads. In these experiments, the reduced derivatives were oxidized in the outer parts of the alginate beads by a second aerobic strain (two different Alcaligenes species), which had the ability to oxidize 4-chloro-2-aminophenol. 

Biotransformations of morphinan alkaloids have been reported for plant, fungal, and mammalian enzymatic systems with emphasis on rather specific reactions such as the reduction of ketones, N- and O-demethylation, and perox-idative transformations. Furuya et al. used immobilized tissue culture cells of Papaver somniferum to accomplish the selective reduction of codeinone (135) to codeine (136) (207) (Scheme 30). Suspension cultures of a well-established cell line of P. somniferum were grown for one week as a source of cell mass for immobilization in calcium alginate. The cells continued to live in the alginate matrix for 6 months maintaining their biological activity. The reduction of co-... 

When cells of Pseudomonas sp. OS-K-29 immobilized on calcium alginate were incubated in 80 1 of a synthetic medium containing 0.2 vol.% of racemic 2,3-DCP, optically pure (S)-2,3-DCP of 100% e.e. was obtained. The immobilized cells could be re-used for a series of continuous reactions, a bioreactor being used for 19 reactions over 50 days without any loss of activity (Fig. 3). Optically pure (i )-2,3-DCP (100% e.e.) was also isolated from the racemate by means of stereospecific assimilation by Alcaligenes sp. DS-K-S38. Highly pure (R)- and (S)-EP of 99.5% e.e. were prepared from (S)- and (i )-2,3-DCP by treatment with aqueous NaOH, respectively [20-221 (Fig. 2). 

Just like activated carbons and hydrous oxides, potentiometric titration can be used to characterize the acid-base surface properties of the resins (4—8,12,15-19). The ionization reactions and the constants (pK values) can be determined according to the titration data. For example, Chen and co-workers reported a successful case of characterization of a cation resin—a calcium alginate based ion exchange resin (CABIER) (17). The study included three steps ... 

Production was also examined on a 5000 L scale in the same way. However, damage due to stirring was found, which was fundamentally the same as on the 100 L scale. Although there was basically no problem concerning the scale-up of the fixed bed reactor and the actual production, the reaction was contaminated by bacteria which in fact degraded the calcium alginate beads during the production [9]. Fixation by acrylamide could be achieved however, scale-up was difficult, and an optical purity decline was sometimes observed. It was considered that acrylamide... 

FIGURE 8.11 First-order reaction rate constants k for heat inactivation, plotted against mass fraction of water w. AP alkaline phosphatase, in skim milk, 80°C. Ec killing of Eschericia coli, in skim milk, 63°C. Ch chymosin, in whey, 80°C. Li lipoxygenase, in sucrose/calcium alginate, 72°C. 

Pantenoic acid is used as a vitamine B2 complex, d- and L-pantolactone are used as chiral intermediates in chemical synthesis. The enantioselective hydrolysis is carried out in the aqueous phase with a substrate concentration of 2.69 M = 350 g L 1 (Fig. 19-17). For the synthesis whole cells are immobilized in calcium alginate beads and used in a fixed bed reactor. The immobilized cells retain more than 90 % of their initial activity after 180 days of continuous use. At the end of the reaction l-pantolactone is extracted and reracemized to d,L-pantolactone, which is recycled to the reactor. The D-pantenoic acid is chemically lactonized to D-pantolactone and extracted. By applying cells from Brevibacterium protophormia the L-lactone is available. The biotransformation eliminates several steps that are necessary in the chemical resolution process (Fig. 19-18). 

A number of hydroxylated water soluble polymers were examined as coreactants with polymer 52 in the absence of calcium alginate, and were judged on the basis of the rate of gel formation and the physical properties of the gel These polymers included sodium alginate, polyvinyl alcohol, and copolymers of HEMA with MAA. Of the polymers tested, best results were obtained with polymer 10a, a copolymer of HEMA with a mole fraction of about 10% MAA, which rapidly produced an elastic gel on exposure to polymer 52 in solution. Simple condensation of the carboxyls in polymer 10a with the epoxide functionality was ruled out as a competing reaction due to the measurable but slow reaction between polymer 52 and poly methacrylic acid. It is, therefore, likely... 

Hydrogel formation may be best rationalized, with reference to Fig. 33. The rapid formation of calcium alginate is accompanied by a slower reaction of polymer 10a (a) and 52 (b) at the surface of the gel (Fig. 331 II). The hydrogel coating eventually becomes a diffusional barrier to further reaction (Fig. 33 III) and can be recovered as an inverse of the alginate matrix by treatment with citrate ion (Fig. 33 IV). 

A considerable amount of interest has been shown in the ion exchange and adsorption properties of algin and kelp, especially by Mongar and Wasserman (9, 53, 136, 137, lUO, 1J 2, 157,162-164, 237, 281, 282), Fully swollen calcium alginate fibers undergo cation exchange reactions with sodium ions accompanied by axial contraction of the fibers and increase in the cross-sectional diameter (108, 141 f 165),... 

We found in our laboratory, a novel lactonohydrolase that catalyzes reversible hydrolysis of various lactones including aldonate lactones and aromatic lactones. The enzyme was crystallized from Fusarium oxysporum and characterized. It has been shown that the enzyme hydrolyzes only D-pantoyl lactone, a chiral intermediate for the commercial production of D-pantothenate, in a racemic mixture of pantoyl lactone and that the enzyme is very useful for the optical resolution of racemic pantoyl lactone (Fig. 3)7. When F. oxysporum mycelia entrapped in calcium alginate gel were incubated in 30% solution of DL-pantoyl lactone, almost stoichiometric hydrolysis of D-pantoyl lactone was observed. After repeated reactions for 150 times over 150 days, the mycelia retained more than 90% of their initial activity. A 1,000... 

Furuya et al. (468) reported the immobilization of P. somniferum cells in calcium alginate. CeUs remained viable for 6 months after immobilization. The cells were used in shake flasks and column bioreactors for the biotransformation of codeinone to codeine. The immobilized cells had a higher biotransformation ratio (70%) than suspended cells (61%). Most of the codeine formed was excreted into the medium (88%). The column bioreactor had a lower biotransformation ratio (42%). The cells in the bioreactor operated at 20°C and an aeration rate of 3.75 vvm (volume gas/volume broth/min) remained catalytically active for 30 days. In a more detailed study on the influence of substrate transport in immobilized cells, it was concluded that limitation of oxygen inside the beads caused deactivation of the cells. However, the reaction rate of the system was not affected by the limitation of oxygen transfer (469). Immobilization of P. 

Huang, K.S., Lai, T.H., and Lin, Y.C. 2007. Using a microfluidic chip and internal gelation reaction for mono-disperse calcium alginate microparticles generation. Front. Biosci. 12 3061-3067. 

Davey, R.B., Sparnon, A.L. and Byard, R.W. (2000) Unusual donor site reactions to calcium alginate dressings . Burns, 26,393. 

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