Method for controlling molecular weight of polyhydroxyalkanoates
US5811272A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1996 |
| Grant date | Sep 22, 1998 |
| Priority date | — |
| Expiry date | Jul 26, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC12P7/625
- WIPO fieldBiotechnology
- WIPO sectorChemistry
Abstract
A method has been developed for control of molecular weight and molecular weight dispersity during production of polyhydroxyalkanoates in genetically engineered organism by control of the level and time of expression of one or more PHA synthases in the organisms. The method was demonstrated by constructing a synthetic operon for PHA production in E. coli in which the level of PHA synthase activity could be tightly controlled by placement of the synthase behind an inducible promoter. Modulation of the total level of PHA synthase activity in the host cell by varying the concentration of the inducer, isopropyl .beta.-D-thiogalactoside (IPTG), was found to effect the molecular weight of the polymer produced in the cell. Specifically, high concentrations of synthase activity were found to yield polymers of low molecular weight while low concentrations of synthase activity yielded polymers of higher molecular weight. Polymer molecular weight dispersity is also proportional to the amount of synthase activity, with less dispersity in polyhydroxyalkanoate compositions produced in expression systems with an initial burst of synthase activity, and higher levels of molecular weight dispersity …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.