A novel matrix for the immobilization of acetylcholinesterase

Şahin, Ferat; Demirel, Gökhan; Tümtürk, Hayrettin

doi:10.1016/j.ijbiomac.2005.10.003

Cited by 66 publications

(27 citation statements)

References 25 publications

(21 reference statements)

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“…The decrease in reaction rate might be attributed to the interaction of enzyme with the functional groups on the surface of beads or large areas of contact between enzyme and support causing large deformation of enzyme conformation. Similar results involving change in K m and V max values of enzyme after immobilization have also reported in the literature [8,[46][47][48].…”

Section: Preparation and Immobilization Of Ecggtsupporting

confidence: 89%

“…The purified EcGGT was immobilized in the Ca-alginate-k-carrageenan beads according to the procedures of Şahin et al [8]. In brief, sodium alginate (0.2 g) and k-carrageenan (0.03 g) were dissolved in 20 mM Tris-HCl buffer (pH 9.0), followed by the addition of 1 ml of EcGGT solution (approximately 4.9 U mg −1 ) to a final volume of 10 ml.…”

Section: Immobilization Of Ecggtmentioning

confidence: 99%

“…IPNs are preferred in a number of biotechnological and biomedical applications because of their certain biophysical properties such as ease of fabrication to various geometrical forms, soft and rubbery texture, and unusual stability to biofluids [39]. A research group has demonstrated the potential of k-carrageenan-related IPNs as supports for the immobilization of biocatalysts [8,40,41]. In this study, Ca-alginate-k-carrageenan polymer blend has also shown to entrap more GGT activity than that of Ca-alginate polymer (Table 1).…”

Section: Preparation and Immobilization Of Ecggtmentioning

confidence: 99%

“…It is a reversibly soluble-insoluble polymer which changes solubility in the presence of calcium [5]. To date, cross-linked alginate has been successfully used for encapsulation of many biological molecules [6][7][8][9][10], owing to the relatively inert aqueous environment within the matrix, the mild room temperature encapsulation process, and high gel porosity allowing high diffusion rates of macromolecules.…”

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confidence: 99%

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Immobilization of Escherichia coli novablue γ-glutamyltranspeptidase in Ca-alginate-k-carrageenan beads

Hung

Hsu

et al. 2008

Appl Biochem Biotechnol

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The recombinant Escherichia coli gamma-glutamyltranspeptidase (EcGGT) was immobilized in Ca-alginate-kappa-carrageenan beads. Effects of alginate concentration, amount of loading enzyme, and bead size on the entrapped activity were investigated. Optimum alginate concentration for EcGGT immobilization was found to be 2% (w/v). Using a loading enzyme concentration of 1.5 mg/g alginate, maximum enzyme activity was observed. With increase in bead size from 1.9 to 3.1 mm, the immobilization efficiency was decreased significantly because of mass transfer resistance. Thermal stability of the free EcGGT was increased as a result of the immobilization. Ca-alginate-kappa-carrageenan-EcGGT beads were suitable for up to six repeated uses, losing only 45% of their initial activity. Upon 30 days of storage the preserved activity of free and immobilized enzyme were found as 4% and 68%, respectively. The synthesis of L: -theanine was performed in 50 mM Tris-HCl buffer (pH 10) containing 25 mM L: -glutamine, 40 mM ethylamine, and 1.5 mg EcGGT/g alginate at 40 degrees C for 12 h, and a conversion rate of 27% was achieved.

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Section: Preparation and Immobilization Of Ecggtsupporting

confidence: 89%

Section: Immobilization Of Ecggtmentioning

confidence: 99%

Section: Preparation and Immobilization Of Ecggtmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Immobilization of Escherichia coli novablue γ-glutamyltranspeptidase in Ca-alginate-k-carrageenan beads

Hung

Hsu

et al. 2008

Appl Biochem Biotechnol

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“…In addition, hydrogel carriers such as alginate, gelatin, and polyacrylamide can provide a protective microenvironment for immobilized enzyme [29,30]. The immobilized E. coli cells harboring BLAI not only retained the biochemical properties of free BLAI but also had long-term stability.…”

Section: Characterization Of Immobilized Cells Harboring Blaimentioning

confidence: 99%

Alginate immobilization of recombinant Escherichia coli whole cells harboring l-arabinose isomerase for l-ribulose production

Zhang

Prabhu

Lee

2009

Bioprocess Biosyst Eng

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Recombinant Escherichia coli whole cells harboring Bacillus licheniformis L-arabinose isomerase (BLAI) were immobilized with alginate. The operational conditions for immobilization were optimized with response surface methodology. Optimal alginate concentration, Ca(2+) concentration, and cell mass loading were 1.8% (w/v), 0.1 M, and 44.5 g L(-1), respectively. The interactions between Ca(2+) concentration, alginate concentration, and initial cell mass were significant. After immobilization of BLAI, cross-linking with 0.1% glutaraldehyde significantly reduced cell leakage. The half-life of immobilized whole cells was 150 days, which was 50-fold longer than that of free cells. In seven repeated batches for L-ribulose production, the productivity was as high as 56.7 g L(-1) h(-1) at 400 g L(-1) substrate concentration. The immobilized cells retained 89% of the initial yield after 33 days of reaction. Immobilization of whole cells harboring BLAI, therefore, makes a suitable biocatalyst for the production of L-ribulose, particularly because of its high stability and low cost.

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Investigation on the development of sturdy bioactive hydrogel beads

Sangeetha

Abraham

2007

J of Applied Polymer Sci

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Biocatalytic hydrogel beads, which retain higher activity, expand, and contract with changes in pH, having biocompatibility, are developed. Composite spherical beads of chitosan having a diameter of 1-2 mm were prepared by ionic gelation using sodium tripolyphosphate (TPP). Above 3% TPP, the activity of the enzyme decreases. The mechanical strength of the chitosan-TPP beads was further improved by the addition of clay or cassava starch granules. The immobilization of protease (fungal, Aspergillus) was done with glutaraldehyde crosslinking. The chitosanstarch hydrogel beads showed significant increase in firmness and stiffness when compared with chitosan-clay beads. The swelling studies show that the particles expand at pH 1.2 and contract at pH 7.4. The activity retention of the immobilized protease was as high as 70% and exhibited a high pH and lower temperature optima than the free enzyme. Chitosan-starch hydrogel beads exhibited degradation peaks at about 90-1108C in TGA analysis. The biocatalyst beads retained 85% of the original catalytic activity even after eight cycles of repeat use. The freeze-dried beads has good storage stability and can be used either as artificial bioreactor systems in detergent or in therapeutic formulations

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A novel matrix for the immobilization of acetylcholinesterase

Cited by 66 publications

References 25 publications

Immobilization of Escherichia coli novablue γ-glutamyltranspeptidase in Ca-alginate-k-carrageenan beads

Immobilization of Escherichia coli novablue γ-glutamyltranspeptidase in Ca-alginate-k-carrageenan beads

Alginate immobilization of recombinant Escherichia coli whole cells harboring l-arabinose isomerase for l-ribulose production

Investigation on the development of sturdy bioactive hydrogel beads

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