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: 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: 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.

Abstract: A host vector system comprising Rhizopus species such as Rhizopus niveus (IFO4810) and a plasmid derived from Phycomycetes such as Mucor, Phycomyces and Absidia wherein the plasmid is contained in a chromosome and/or cytoplasm of the Rhizopus species. The host vector system is suitable for the extracellular production of proteins and enzymes. A process for preparing the host vector system is also provided.

Abstract: The present invention relates to plasmids whose hosts can be Escherichia coli and some kinds of yeasts, namely, shuttle vectors, as well as to processes for producing said plasmids. There are provided in the present invention (1) plasmids containing an autonomously replicating sequence of Candida maltosa, Leu 2 gene derived from Saccharomyces cerevisiae and an ampicillin resistance gene and (2) plasmids further containing a tetracycline resistance gene as well as the genes described in (1).The plasmids (shuttle vectors) of the present invention can be utilized as follows. A useful foreign gene is inserted into plasmids of the present invention; using the resulting new plasid, Escherichia coli is transformed and cultured in order to obtain the plasmid in a large amount; and using this plasmid, Saccharomyces cerevisiae or Candida maltosa as a host is allowed to produce useful substances such as hormones and enzymes on a large scale.

Abstract: A cycloheximide resistant gene of the present invention can be produced by cultivating yeast belonging to Candida genus and by cleaving a cycloheximide resistant gene from the yeast using restriction enzymes XbaI and Sau3AI.By incorporating the cycloheximide resistant gene together with the gene for useful substance into a plasmid, the transformant producing useful substance can be readily detected.