Calcium alginate beads

D-Pantolactone and L-pantolactone are used as chiral intermediates in chemical synthesis, whereas pantoic acid is used as a vitamin B2 complex. All can be obtained from racemic mixtures by consecutive enzymatic hydrolysis and extraction. Subsequently, the desired hydrolysed enantiomer is lactonized, extracted and crystallized (Figure 4.6). The nondesired enantiomer is reracemized and recycled into the plug-flow reactor [33,34]. Herewith, a conversion of 90-95% is reached, meaning that the resolution of racemic mixtures is an alternative to a possible chiral synthesis. The applied y-lactonase from Fusarium oxysporum in the form of resting whole cells immobilized in calcium alginate beads retains more than 90% of its initial activity even after 180 days of continuous use. The biotransformation yielding D-pantolactone in a fixed-bed reactor skips several steps here that are necessary in the chemical resolution. Hence, the illustrated process carried out by Fuji Chemical Industries Co., Ltd is an elegant way for resolution of racemic mixtures. 

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,... 

Roy, I. and Gupta, M.N., Hydrolysis of starch by a mixture of glucoamylase and pullulanase entrapped individually in calcium alginate beads, Enzyme Microbial Tech., 34 (2004) 26-32. 

The bioconversion of (4/ )-(-)-limonene to (4/ )-(-)-a-terpineol by immobilised fungal mycelia of Penicillium digitatum was described more recently [86]. The fungi were immobilised in Calcium alginate beads. These beads remained active for at least 14 days when they were stored at 4°C. a-Terpineol production by the fungus was 12.83 mg/g beads per day, producing a 45.81% bioconversion of substrate. The optimum conversion temperature was 28°C and the optimum pH was 4.5. The highest... 

Simultaneous L-lactic acid fermentation (by Rhizopus oryzae immobilized in calcium alginate beads) and separation was carried out using a three-phase fluidized-bed bioreactor as a fermenter (F), an external electrodialyzer as a separator, and a pump to recycle the fermentation broth between the bioreactor and the separator. In this way, the experimental specific lactate productivity and yield practically coincided with those obtained in the CaC03-buffered fermentation process (Xuemei et al., 1999), thus confirming the capability of the combined system to alleviate product inhibition without any addition of alkali or alkali salts. It was also shown that the adoption of ED-F for the production of inoculum reduced variability in inoculum quality, thus shortening the length of the lag phase of L-lactate production practically to zero as compared to that observed using an inoculum... 

Similarly, the encapsulation of various molecules (BSA and dextrans with various molecular weights) in calcium alginate beads coated with chitosan has been reported [178,179]. Their release has been compared and the influence of the conformation, the chemical composition and the molecular weight of the encapsulated materials has been analyzed [178]. The ionic interactions between alginate and chitosan at different pH values are depicted in Fig. 10. 

Lee, K. Y., and Heo, T. R. (2000), Survival of Bifidobacterium longum immobilized in calcium alginate beads in simulated gastric juices and bile salt solution, Appl. Environ. Microbiol., 66, 869-873. 

Mumper, R.J. Hoffman, A.S. Puolakkainen, P.A. Bouchard, L.S. Gombotz, W.R. Calcium-alginate beads for the oral delivery of transforming growth factor-betal (TGF-Betal) stabilization of TGF-betal by the addition of polyacrylic acid within acid-treated beads. J. Controlled Release 1994, 30, 241-251. 

Torre ML, Giunchedi P, Maggi L, et al. Formulation and characterization of calcium alginate beads containing ampicillin. Pharm Dev Tech 1998 3(2) 193-198. 

Lim LY, Wan ESC. Propranolol hydrochloride binding in calcium alginate beads. Drug Dev Ind Pharm 1997 23(10) 973-980. 

A new bioreactor, consisting of a liquid-gas two-phase system, was devised for utilization with berberine-secreting T. minus cells immobilized in calcium alginate beads. The cells were alternately soaked in medium, and then exposed to air, and the maximum yield of berberine production was 875 mg/L. The berberine productivity of immobilized cells was as high as that of freely suspended cells under such conditions of batch culture. In addition, the rate of production of berberine by the immobilized cells remained constant at a high value (50 mg/L/day) for 60 days of semicontinuous culture, achieved by the renewal of medium at 10 day intervals [154]. 

Recent examples of process improvement have been reported by Davison and Thomson [11] and Kaufman et al. [12]. They studied the simultaneous fermentation and recovery of lactic acid in a biparticle fluidized-bed reactor using L. delbreuckii as the biocatalyst. The immobilized bacterial cells (on calcium alginate beads of 0.7-0.8 mm diameter) were fluidized in the liquid media in a column reactor (see Fig. 1). During fermentation, solid particles of lactic acid adsorbent (polyvinylpyridine resin) are added batchwise to the top of the reactor, and fall countercurrently through the biocatalyst. After the adsorbents have fallen through the reactor, they are recovered and the adsorbed lactic acid is recovered. The adsorbents not only remove acid produced but also effectively maintain the broth pH at optimal levels. The increase in lactic acid production is significant. The reported volumetric productivity of 4.6 g/l/h was a 12-fold increase over the reactor without the adsorbents. 

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... 

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). 

Cyanovaleramide is used as intermediate for the synthesis of the DuPont herbicide azafenidine (Fig. 19-39). The whole cells from Pseudomonas chlororaphis are immobilized in calcium alginate beads. The biotransformation itself is catalyzed by a nitrile hydratase that converts a nitrile into the corresponding amide by addition of water. Nitrile hydratases belonging to the enzyme class of lyases (E.C. 4) are not be... 

Ferreira, L., Afonso, C., Vila, R.H., Alfaia, A., and Ribeiro, M.H.L. 2008. Evaluation of the effect of high pressure on naringin hydrolysis in grapefruit juice with naringinase immobilized in calcium alginate beads. Food Technology and Biotechnology 46 146-150. 

The primary methods used in cell immobilization are surface adhesion, covalent attachment and entrapment. Surface adhesion involves adsorption of cells to microcarriers such as calcium alginate beads, collagen-coated plastic beads, diatomite silica, and dextrans [68]. Immobilization can be achieved simply by suspending the cells and microcarrier together under slow agitation. Examples of such systems include immobilized bacteria for waste water treatment and adsorbed Azotobacter vinelandii on Cellex E for nitrogen fixation... 

Pandey AK, Pandey SD, Misra V and Srimal AK (2003) Removal of chromium and reduction of toxicity to Microtox system from tannery ffluent by the use of calcium alginate beads containing humic add. Chemosphere 51 329-333. 

Figure 3. Somatic seeds. Alfalfa somatic embryos encapsulated in calcium alginate beads. Each capsule is approximately 4 mm in diameter.

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