K-carrageenan gel

Subsequent work by Johansson and Lofroth [183] compared this result with those obtained from Brownian dynamics simulation of hard-sphere diffusion in polymer networks of wormlike chains. They concluded that their theory gave excellent agreement for small particles. For larger particles, the theory predicted a faster diffusion than was observed. They have also compared the diffusion coefficients from Eq. (73) to the experimental values [182] for diffusion of poly(ethylene glycol) in k-carrageenan gels and solutions. It was found that their theory can successfully predict the diffusion of solutes in both flexible and stiff polymer systems. Equation (73) is an example of the so-called stretched exponential function discussed further later. 

Fumarase. The development and use of this immobilized enzyme by Tanabe Seiyaku for production of L-malic acid is very similar to that of aspartase ( 3). Lysed Brevibacterium ammoniagenes or B. flavin cells are treated with bile acid to destroy enzymatic activity which converts fumarate to succinate. As with aspartase, the cells can be immobilized in polyacrylamide or k-carrageenan gels. Using a substrate stream of 1 M sodium fumarate at pH 7.0 and 37°C, L-malic acid of high purity has been produced since 1974 by a continuous, automated process (3,39) for example, using a 1000-L fixed-bed bioreactor, 42.2 kg L-malic acid per hour was produced continuously for 6 months. 

Excluded volume effects may increase the effective concentration of K-carrageenan and the reduction of available water for each macromolecule may lead to increased inter- and intra-helix interactions in the polysaccharide. In the presence of other proteins (i.e. milk proteins) K-carrageenan gel formation involved mainly carrageenan - carrageenan cross-linkages and not polysaccharide - protein interactions.5,9... 

Synergistic effects are obtained by combining carrageenans with other gum types such as brittle k-carrageenan gels may be softened with locust bean gum. 

Kara, S., Arda, E., Kavzak, B., Pekcan, O., 2006. Phase transitions of k-carrageenan gels in various types of salts. J. Appl. Polym. Sci. 102, 3008-3016. 

Hunik JH, van den Hoogen MP, de Boer W, Smit M, Tramper J. Quantitative determination of the spatial distribution of nitrosomonas europaea and nitro-bacter agilis cells immobilized in k-carrageenan gel beads by a specific fluorescent-antibody labelling technique. Applied and Environmental Microbiology 1993 59 1951-4. 

The solid character of K-carrageenan gels arises from the formation of a three-dimensional network, which extends continuously through the entire volume and entraps the dispersed... 

Fig. 8. Variation of G (black symbols) and G" (white symbols) with angular frequency for different KCl concentrations (mmol/dm ) for 1.0% K-carrageenan gels at 25 C. (a) 5 (circles), 40 (triangles), 80 (inverted triangles), (b) 90 (diamonds), 100 (dotted circles) and 200 (dotted triangles). Experimental conditions correspond to region III in Fig. 3.

Hunik, J. H., van den Hoogen, M. P, de Boer, W, et al.. Quantitative Determination of the Spatial Distribution of Nitrosomonas europaea and Nitrobacter agilis Cells Immobilized in k-Carrageenan Gel Beads by a Specific Fluorescent-Antibody Labelling Technique, Applied and Environmental Microbiology, 59 1951-1954 (1993). 

---