Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing oxygen-containing organic compound
Patent
1993-07-26
1995-06-06
Knode, Marian C.
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing oxygen-containing organic compound
435146, C12P 762, C12P 742
Patent
active
054222575
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to the field of organic synthesis. In particular, it has as its object a novel process for the preparation of poly-.beta.-hydroxyoctanoic acid, a polymer formed of repeating units of formula ##STR1## which process allows the preparation of said acid in good yields and without significant degradation of the polymer.
The process of the invention is based on a method of extraction of poly-.beta.-hydroxyoctanoic acid from a culture of bacteria containing it, by means of an organic solvent.
PRIOR ART
The poly-hydroxyalkanoic acids are storage compounds which can be found in certain families of bacteria. These acids deposit themselves in aggregate form in the cytoplasmic solution when the cells are grown in a carbon-rich medium and wherein one of the nutrients is growth-limiting.
Several methods of extraction of these acids have been described in the literature. They concern most particularly the production of poly-.beta.-hydroxybutanoic acid or of poly-.beta.-hydroxyoctanoic acid for which there has been suggested an extraction by means of chlorinated solvents, for example chloroform or methylene chloride, starting from cells obtained via cold-drying, more specifically by lyophilization. Examples of such methods are described in Appl. Environ. Microbiol., 55 (1989), 1949; Appl. Environ. Microbiol., 54 (1988), 1977 and Appl. Environ. Microbiol., 45 (1983), 71.
The use of chlorinated solvents on the lyophilized biomass comes up against two major inconvenients. On the one hand, such solvents are to be avoided, as much as possible, in large scale industrial operations for obvious reasons of protection of the environment, and, on the other hand, the lyophilization process is particularly expensive.
DESCRIPTION OF THE INVENTION
The present inventions brings a novel solution to this problem. In its general principle, the process of the invention consists in growing appropriate bacteria in an adequate nutrient medium. The bacteria are subsequently separated, after fermentation, by the usual techniques, for example centrifugation, and the wet biomass thus obtained is suspended in acetone or isopropanol or any other dehydrating solvent known from the prior art. Thus, after separation, the still wet biomass is stirred in the chosen suspension organic solvent until an homogeneous suspension is obtained. The separation of the solid cellular mass from the suspension is carried out by the usual methods, for example decantation, filtration or centrifugation. Simple filtration by means of a Buchner filter allows the separation of the bacteria cells in the form of an already dry powder. A subsequent drying can be optionally carried out by direct exposure to air of the separated solid.
It should be noted that, although poly-.beta.-hydroxyoctanoic acid is completely soluble in anhydrous acetone, the presence of water, even in very small quantities, renders the polymer quite insoluble.
The extraction of poly-.beta.-hydroxyoctanoic acid takes place in nonchlorinated organic solvents defined by the following group: acetone, methylisobutylketone, diisopropylketone, diethylketone, ethyl acetate, propyl acetate, butyl acetate, diethyl ether, diisopropyl ether and tetrahydrofuran. Preferably, acetone or tetrahydrofuran are used. In the absence of water, these solvents make it possible to completely dissolve the polymer obtained by simple stirring at room temperature. The relative proportion of the mass of dried cells with regard to acetone or tetrahydrofuran is comprised between about 7.5 and 15% (weight/volume).
By filtration of the obtained suspension and evaporation of the separated clear solution, the desired product is finally obtained in the form of a translucent polymeric film, consisting essentially of poly-.beta.-hydroxyoctanoic acid.
As indicated above, the intracellular formation of poly-.beta.-hydroxyalkanoic acids has been observed in a great number of bacteria families. In particular, fermentation of bacteria of the Pseudomonas genus, in a nutrient medium wherein one of the agent
REFERENCES:
patent: 3275610 (1966-09-01), Coty
patent: 4140741 (1979-02-01), Lafferty et al.
patent: 4968611 (1990-11-01), Traussnig et al.
Haywood et al., "Accumulation of a Polyhydroxyalkanoth-containing Primarily 3-hydroxydicanrth from Sample Carbohydrate Substrates by Pseudomas" pp. strain NCIMP 40135; Chemical Abstracts, 114:20781f, 1991.
Kirk-Othmer, "Acetone", pp. 176-194, Kirk-Othmer Encyclopedia of Chemical Technology, Pub: John Wiley and Sons, 1978.
Kirk-Othmer, "Ethus", pp. 866-876, Kirk-Othmer Encyclopedia of Chemical Technology, Pub: John Wiley and Sons, 1978.
Firmenich SA
Knode Marian C.
Prats Francisco C.
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