Mitsubishi Gas Chemical Company, Inc.

Asahi Kasei Kogyo Kabushiki Kaisha

Mitsubishi Kasei Corporation

Yoshiharu Doi

Minoru Akiyama

An improved method for producing a microbial polyester comprising 3-hydroxybutyrate monomer units is disclosed, in which a strain belonging to the genus Alcaligenes is cultured in a liquid medium containing a carbon source selected from specific long chain fatty acids and derivatives thereof. The produced microbial polyester is useful in plastics and polymers which are free from environmental pollution problems, and in implanting materials and drug carriers, recovery of which is not necessary.

Method for producing a microbial polyester

A random copolymer comprising less than 50 mole % of D-(-)-3-hydroxybutyrate units and more than 50 mole % of D-(-)-3-hydroxyvalerate units, the percentages being based on the total amount of the two units. A process for producing the random copolymer which comprises (1) cultivating a microorganism having the ability to produce poly(3-hydroxybutyrate) to grow and proliferate the cells of the microorganism, (2) cultivating the cells in the presence of a valeric acid or in the copresence of a valeric acid and an n-butyric acid while limiting the amount of nitrogen or phosphorus to produce and accumulate a random copolymer comprising D-(-)-3-hydroxybutyrate units and D-(-)-3-hydroxyvalerate units within the cells, and thereafter, (3) recovering the copolymer from the cells.

Random copolymer comprising D-(-)-3-hydroxybutyrate units and

According to the present invention, a novel copolyester comprising 3-hydroxybutyrate unit, 3-hydroxyvalerate unit and 5-hydroxyvalerate unit; 3-hydroxybutyrate unit and 4-hydroxybutyrate unit; or 3-hydroxybutyrate unit, 4-hydroxybutyrate unit and 3-hydroxyvalerate unit is easily obtained. Further, since the copolyester according to the present invention has various excellent specific properties, it is extremely suitable as the biomedical materials such as suture material and fixation materials for bone fracture, and its application to various fields such as the slow-releasing system, etc. is expected.

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Yokohama, Japan

Yoshiharu Doi