Abstract: This invention relates to a method of producing polyesters resulting from homopolymerization or copolymerization of a 3-hydroxyalkanoic acid(s) and having biodegradability and good physical properties using yeasts as hosts. By constructing at least one enzyme gene involved in polyester synthesis by adding a DNA coding a peroxisome-targeting signal, introducing an enzyme gene expression cassette containing that gene into yeast, and cultivating the thus-obtained transformant, it becomes possible to cause accumulation of a polyester resulting from homopolymerization or copolymerization of a 3-hydroxyalkanoic acid(s) in yeast cells and recover the polyester from the culture.

Abstract: The present invention provides a production method of a copolymeric polyester which comprises culturing an ACT1 gene promoter shown under SEQ ID NO: 9, a GAP3 gene promoter shown under SEQ ID NO: 10; a PMA1 gene promoter shown under SEQ ID NO: 11, and, a TEF1 gene promoter shown under SEQ ID NO: 12; a plasmid which contains the gene expression unit comprising said promoter; a transformed cell as resulting from transformation of the said plasmid; and said transformed cell.

Abstract: Process for producing a copolyester of desired quality at low cost with high productivity, preferably a process for producing P(3HB-co-3HH) of 4 mol % or more 3HH content with a productivity as high as 40 g/L or more. In particular, a process for producing a copolyester of 3HB and 3HH comprising culturing a microorganism with the use of, as a carbon source, a fat or oil containing lauric acid as a constituent fatty acid under such conditions that phosphorus as a source of nutrition is limited.

Abstract: A gene expression cassette comprising an Aeromonas caviae-origin polyhydroxyalkanoic acid (PHA) synthase gene having a mutation introduced thereinto and a promoter and a terminator acting in a yeast; a transformant constructed by transferring the above gene expression cassette into a yeast; and a process for producing a polyester using the above transformant. Thus, it becomes possible to efficiently produce a copolymerized polyester having a high biodegradability and excellent properties by copolymerizing 3-hydroxyalkanoic acids in a yeast.

Abstract: This invention relates to a method of producing polyesters resulting from homopolymerization or copolymerization of a 3-hydroxyalkanoic acid(s) and having biodegradability and good physical properties using yeasts as hosts. By constructing at least one enzyme gene involved in polyester synthesis by adding a DNA coding a peroxisome-targeting signal, introducing an enzyme gene expression cassette containing that gene into yeast, and cultivating the thus-obtained transformant, it becomes possible to cause accumulation of a polyester resulting from homopolymerization or copolymerization of a 3-hydroxyalkanoic acid(s) in yeast cells and recover the polyester from the culture.

Abstract: The present invention relates to a gene coding for a copolyester-synthesizing enzyme, a microorganism which utilizes the gene for the fermentative synthesis of a polyester, and a method of producing a polyester with the aid of the microorganism. More particularly, the present invention relates to a gene which functions in a host organism and, by an enzyme, synthesizes a plastic-like polymer degradable under the action of microorganisms in the natural environment (the soil, river or sea). The present invention also, more particularly, relates to a transformant derived from the host organism by transformation with the gene and having an improved ability to fermentatively synthesize a plastic-like polymer, and a method of producing a copolyester with the aid of the transformant.

Abstract: The invention provides a yeast in which a specific gene alone has been disrupted and to which auxotrophy is impared to construct a system for producing an industrially useful substance through gene recombination by utilizing characteristics of a yeast. In the practice of the invention, a yeast strain in which ADE1 gene has been disrupted is constructed by homologous recombination with a chromosomal DNA by using an ADE1 gene fragment encoding phosphoribosylaminoimidazole succinocarboxamide synthase (EC6.3.2.6) of Candida maltosa. In the practice of the invention, then, this disrupted strain is transformed by a gene expression cassette containing a biodegradable polyester synthase gene and the obtained transformant is cultured to thereby produce biodegradable polyester.

Abstract: Process for producing a copolyester of desired quality at low cost with high productivity, preferably a process for producing P(3HB-co-3HH) of 4 mol % or more 3HH content with a productivity as high as 40 g/L or more. In particular, a process for producing a copolyester of 3HB and 3HH comprising culturing a microorganism with the use of, as a carbon source, a fat or oil containing lauric acid as a constituent fatty acid under such conditions that phosphorus as a source of nutrition is limited.

Abstract: The object of the present invention is to develop a technology to optionally control a composition of a biodegradable copolyester with maintaining low cost and high productivity. The present invention consists in a culture method in producing a copolyester by a microorganism, which comprises controlling a specific substrate feed rate of an oil or fat to be used as a carbon source at a constant value throughout the whole culture period, or a method, which comprises applying a different specific substrate feed rate of an oil or fat used as a carbon source between a cell growth phase and a polyester accumulation phase in a culture and controlling the rate at a constant value during the respective phases. Furthermore, the present invention also consists in a culture method, which comprises controlling the composition of the produced copolyester by selecting the species and/or the control value for the specific substrate feed rate.

Abstract: The present invention relates to a gene coding for a copolyester-synthesizing enzyme, a microorganism which utilizes said gene for the fermentative synthesis of a polyester, and a method of producing a polyester with the aid of said microorganism. More particularly, the present invention relates to a gene which functions in a host organism and is related to synthesize, by an enzyme, a plastic-like polymer degradable under the action of microorganisms in the natural environment (the soil, river or sea), a transformant derived from said host organism by transformation with said gene and having an improved ability to fermentatively synthesize a plastic-like polymer, and a method of producing a copolyester with the aid of said transformant.