US5149644A
Expired / Lapsed
US
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Process for the release of poly(3-hydroxy carboxylic acids)
Assignee: PCD Polymere GmbH
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Filing: 1990-12-26
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Granted: 1992-09-22
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Expires: 2010-12-26
Abstract
Abstract Process for releasing poly(3-hydroxy carboxylic acid) granules from cells of Gram-negative bacteria containing the latter, by expression of a cloned natural or chimeric lysis gene, in which, before induction of lysis gene expression, the ionic strength of doubly charged cations is increased to between 0.05 and 0.5 mol/1, the expression of the lysis gene is induced by raising the temperature, the cells are harvested, and the still wet cells are resuspended in water or buffer solutions, which results in the release of the polymer granules by spontaneous lysis.
Inventors
- 👤 Werner Lubitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:07
CPC Classifications
C; C12; C12P; C12P7/00; C12P7/62; C12P7/625; C12N; C12N9/00; C12N9/14
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
92 words
Process for releasing poly(3-hydroxy carboxylic acid) granules from cells of Gram-negative bacteria containing the latter and divalent cations, by expression of a cloned natural or chimeric lysis gene, wherein, before induction of lysis gene expression, the ionic concentration of divalent cations is increased to between 0.05 and 0.05 mol/l, the expression of the lysis gene is induced by raising the temperature, the cells are harvested by gentle centrifugation, and the still wet cells are resuspended in water or buffer solutions, which results in the release of the polymer granules by spontaneous lysis.
Claim 2
Dependent Claim
92 words
Process for releasing poly(3-hydroxy carboxylic acid) granules from cells of Gram-negative bacteria containing the latter and divalent cations, by expression of a cloned natural or chimeric lysis gene, wherein, before induction of lysis gene expression, the ionic concentration of divalent cations is increased to between 0.05 and 0.05 mol/l, the expression of the lysis gene is induced by raising the temperature, the cells are harvested by gentle centrifugation, and the still wet cells are resuspended in water or buffer solutions, which results in the release of the polymer granules by spontaneous lysis.
Claim 3
Dependent Claim
19 words
Process according to claim 1, wherein the lysis gene employed is the cloned lysis gene E of bacteriophage PhiX174.
Claim 4
Dependent Claim
20 words
Process according to claim 1, wherein the concentration of the divalent cations is raised to between 0.1 and 0.3 mol/l.
Claim 5
Dependent Claim
22 words
Process according to claim 1, wherein the concentration of the divalent cations is raised by adding MgSO 4 or CaCO 3 .
Claim 6
Dependent Claim
12 words
Process according to claim 1, wherein Alcaligenes are employed as Gram-negative bacteria.
Claim 7
Dependent Claim
14 words
Process according to claim 1, wherein transformed E. coli are employed as Gram-negative bacteria.
References Cited (Backward Citations)
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US4520016A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-22 | 1996-03-23 | 1996-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-22 | 2000-03-23 | 2000-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-22 | 2004-03-23 | 2004-09-22 | $7700.00 | Window Closed / Lapsed |