Molecular weight characterization of poly[( R)-3-hydroxybutyrate] synthesized by genetically engineered strains of Escherichia coli
This study investigated the relationship of growth conditions, host strains and molecular weights of poly[( R)-3-hydroxybutyrate] [P(3HB)] synthesized by genetically engineered Escherichia coli. Various PHA synthases belonging to types I–IV enzymes were expressed in E. coli JM109 under the same expe...
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Published in | Polymer degradation and stability Vol. 91; no. 5; pp. 1138 - 1146 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford
Elsevier Ltd
01.05.2006
Elsevier Science |
Subjects | |
Online Access | Get full text |
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Summary: | This study investigated the relationship of growth conditions, host strains and molecular weights of poly[(
R)-3-hydroxybutyrate] [P(3HB)] synthesized by genetically engineered
Escherichia coli. Various PHA synthases belonging to types I–IV enzymes were expressed in
E. coli JM109 under the same experimental conditions, and the molecular weights of the polymers were characterized by gel permeation chromatography. The results demonstrate that P(3HB) polymers have varied molecular weights and polydispersities dependent on the characteristics of the individual PHA synthase employed. P(3HB) with high number-average molecular weights (
M
n) [(1.5–4.0)
×
10
6] and narrow polydispersities (1.6–1.8) were synthesized by PHA synthases from
Ralstonia eutropha (type I),
Delftia acidovorans (type I) and
Allochromatium vinosum (type III). Contrary to these, P(3HB) with relatively low
M
n [(0.17–0.79)
×
10
6] and broad polydispersities (2.2–9.0) were synthesized by PHA synthases from
Aeromonas caviae (type I),
Pseudomonas sp. 61-3 (type II) and
Bacillus sp. INT005 (type IV). Furthermore, the molecular weights of P(3HB) synthesized under various culture conditions, in various hosts of
E. coli and by mutants of PHA synthase were characterized. It was found that, in addition to culture pH [Kusaka et al. Appl Microbiol Biotechnol 1997;47:140], other variances such as culture temperature, host strain and use of mutants are effective in changing polymer molecular weight. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 ObjectType-Article-2 ObjectType-Feature-1 |
ISSN: | 0141-3910 1873-2321 |
DOI: | 10.1016/j.polymdegradstab.2005.07.006 |