Alginic acid alginate beads

Alginic acid Alginate beads have been extensively used for the controlled delivery of many cationic drugs and various growth factors. Khanlari and Dube (2013) and Nair and Laurencin (2006)... 

In fermentation for the production of acetic acid, ethyl alcohol is used in an aerobic process. In an ethanol oxidation process, the biocatalyst Acetobacter aceti was used to convert ethanol to acetic acid under aerobic conditions. A continuous fermentation for vinegar production was proposed for utilisation of non-viable A. aceti immobilised on the surface of alginate beads. 

Lactic acid bacteria were immobilized in Ca-alginate beads prepared from different concentration of Na-alginate (1.0%, 2.0%, 4.0%, 6.0% and 8.0% w/v) and their fermentation efficiencies were investigated in liquid pineapple waste containing 31.3 gL of glucose... 

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. 

A procedure for immobilization of a P. stutzeri UP-1 strain using sodium alginate was reported [133], This strain does not perform sulfur-specific desulfurization, but degrades DBT via the Kodama pathway. Nevertheless, the report discussed immobilization of the biocatalyst cells in alginate beads with successful biocatalyst recovery and regeneration for a period of 600 h. However, the immobilized biocatalyst did decrease in specific activity, although the extent of loss was not discussed. The biocatalyst was separated after every 100 h of treatment, washed with saline and a boric acid solution and reused in subsequent experiment. The non-immobilized cells were shown to loose activity gradually with complete loss of activity after four repeat runs of 20 hour each. The report does not mention any control runs, which leaves the question of DBT disappearance via adsorption on immobilized beads unanswered and likewise the claim of a better immobilized biocatalyst. 

Transfer the alginate beads into a solution of 4% (v/v) glutaraldehyde in 0.1 M2-(N-morpholino) ethanesulphonic acid-NaOH (pH 5.8) that contained 0.4 M glucose. 

Immerse the alginate beads according to a modified method of Akert and Sandri (44) for 3,16, or 20 h at 4°C in the ZIO mixture, which consisted of 3.75% zinc (powder) and 1.25% resublimed iodine crystals in 50 mM 2-(N-morpholino) ethanesulphonic acid-NaOH buffer (pH 5.8) containing 0.2 M glucose and 1% Os04 (MG buffer). 

A strain of Pseudomonas aeruginosa has been recently described, which shows the opposite enantioselectivity, converting racemic arylaminonitriles efficientiy into the D-amino acids. Again, whole-cell biocatalysis worked well, the cells being entrapped in alginate beads. It is unclear whether this biotransformation involves an amide intermediate. 

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... 

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. 

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. 

In another study, Liu et al. [66] used a PEM in place of an OTS SAM to create a new type of membrane for encapsulation of cultured cells. The PEM was composed of several alternating layers of poly(lysine) and alginate, capped with an amphiphilic terpolymer synthesized from yV,/V-dioctadecylcarbamoyl propionic acid, hydrox-yethylacrylate, and styrene sulfonate. The octadecyl chains provided a hydrophobic surface on which the acrylatePC was fused, then photopolymerized (Fig. 2). Coating alginate beads with the PEM/HBM multilayer significantly reduced the release... 

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). 

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