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Chitosan flocculation: An effective method for immobilization of E. coli for biocatalytic processes.

Rehn, Gustav LU ; Grey, Carl LU ; Branneby, Cecilia and Adlercreutz, Patrick LU (2013) In Journal of Biotechnology 165(2). p.138-144
Abstract
Immobilization of Escherichia coli cells containing a ω-transaminase was carried out by flocculation with chitosan and the preparation was used in asymmetric synthesis of (S)-4'-cyano-α-methylbenzylamine, recycled in five consecutive batches. Chitosans with different molecular weights and degrees of acetylation were compared and effects of varying the chitosan properties, cell concentration and ratio of cells to chitosan were studied. Immobilization was achieved by increasing the pH to slightly alkaline, which induced the formation of large fast sedimenting flocs. Although an effective immobilization was obtained using most types of chitosan, high molecular weight and low degree of acetylation were considered favourable properties,... (More)
Immobilization of Escherichia coli cells containing a ω-transaminase was carried out by flocculation with chitosan and the preparation was used in asymmetric synthesis of (S)-4'-cyano-α-methylbenzylamine, recycled in five consecutive batches. Chitosans with different molecular weights and degrees of acetylation were compared and effects of varying the chitosan properties, cell concentration and ratio of cells to chitosan were studied. Immobilization was achieved by increasing the pH to slightly alkaline, which induced the formation of large fast sedimenting flocs. Although an effective immobilization was obtained using most types of chitosan, high molecular weight and low degree of acetylation were considered favourable properties, resulting in good floc stability and quick sedimentation. It was found that it was possible to affect the floc characteristics, by changing the ratio of cells to chitosan in such a way that preparations resembling either entrapped or cross-linked cells could be obtained. The volume of the sedimented preparation decreased approximately 50% when increasing the cell to chitosan ratio from 2g/g to 10g/g at a constant amount of cells. Despite very high concentrations of cells (10-100g cells/g chitosan) in the flocculated preparations, diffusion limitations were minimal. Flocculation with chitosan was considered a simple and effective method for immobilization of E. coli cells for biocatalytic processes. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Biotechnology
volume
165
issue
2
pages
138 - 144
publisher
Elsevier
external identifiers
  • wos:000319244000010
  • pmid:23562827
  • scopus:84876725866
ISSN
1873-4863
DOI
10.1016/j.jbiotec.2013.03.014
language
English
LU publication?
yes
id
2aacea13-3baa-4354-8918-046d654f53e4 (old id 3734070)
date added to LUP
2013-05-28 16:32:35
date last changed
2019-02-20 01:43:31
@article{2aacea13-3baa-4354-8918-046d654f53e4,
  abstract     = {Immobilization of Escherichia coli cells containing a ω-transaminase was carried out by flocculation with chitosan and the preparation was used in asymmetric synthesis of (S)-4'-cyano-α-methylbenzylamine, recycled in five consecutive batches. Chitosans with different molecular weights and degrees of acetylation were compared and effects of varying the chitosan properties, cell concentration and ratio of cells to chitosan were studied. Immobilization was achieved by increasing the pH to slightly alkaline, which induced the formation of large fast sedimenting flocs. Although an effective immobilization was obtained using most types of chitosan, high molecular weight and low degree of acetylation were considered favourable properties, resulting in good floc stability and quick sedimentation. It was found that it was possible to affect the floc characteristics, by changing the ratio of cells to chitosan in such a way that preparations resembling either entrapped or cross-linked cells could be obtained. The volume of the sedimented preparation decreased approximately 50% when increasing the cell to chitosan ratio from 2g/g to 10g/g at a constant amount of cells. Despite very high concentrations of cells (10-100g cells/g chitosan) in the flocculated preparations, diffusion limitations were minimal. Flocculation with chitosan was considered a simple and effective method for immobilization of E. coli cells for biocatalytic processes.},
  author       = {Rehn, Gustav and Grey, Carl and Branneby, Cecilia and Adlercreutz, Patrick},
  issn         = {1873-4863},
  language     = {eng},
  number       = {2},
  pages        = {138--144},
  publisher    = {Elsevier},
  series       = {Journal of Biotechnology},
  title        = {Chitosan flocculation: An effective method for immobilization of E. coli for biocatalytic processes.},
  url          = {http://dx.doi.org/10.1016/j.jbiotec.2013.03.014},
  volume       = {165},
  year         = {2013},
}