TRANSFORMANT AND METHOD FOR PRODUCING SAME, AND METHOD FOR PRODUCING LACTIC ACID

Provided are: a transformant that is capable of producing lactic acid at a high productivity without requiring neutralization with an alkaline agent, and has excellent lactic acid production ability and excellent proliferation potency; a method for producing the transformant; and a method for producing lactic acid using the transformant. A transformant characterized in that: the host thereof is Schizosaccharomyces pombe; 3-5 copies of a human-derived lactate dehydrogenase gene are integrated thereinto; and some genes belonging to a gene group encoding pyruvate decarboxylase of the Schizosaccharomyces pombe host are deleted or deactivated therein. A transformant characterized in that: when the transformant is inoculated into 100 ml of a liquid medium in a 500 ml Sakaguchi flask, said liquid medium comprising 1% of yeast extract, 2% of peptone and 6% of glucose, at an initial cell concentration of 0.04 g (dcw)/l and then cultured for 20 hours at a temperature of 32°C under shaking at 110 rpm and a shaking width of 7 cm, the cell concentration of the liquid culture is 4.0 g (dcw)/l or greater; and, when the cells obtained by culturing for 20 hours under the same conditions as described above are inoculated into a 11.1% aqueous glucose solution at an initial cell concentration of 36 g (in terms of dry cells)/l and then fermented for 3 hours at a temperature of 32°C under shaking at 110 rpm and a shaking width of 7 cm, the lactic acid concentration of the fermented liquor is 80 g/l or greater. A method for producing lactic acid using any of the aforesaid transformants. L'invention concerne : un transformant qui est capable de produire de l'acide lactique à une productivité élevée sans avoir à être neutralisé à l'aide d'un agent alcalin, ayant une excellente capacité de production d'acide lactique et un excellent pouvoir de prolifération; un procédé de production du transformant; et un procédé de production d'acide lactique l'utilisant. Le transformant selon l'invention est caractérisé en ce que : son hôte est Schizosaccharomyces pombe; 3 à 5 copies du gène de la lactate déshydrogénase d'origine humaine sont intégrées; et certains gènes appartenant à un groupe de gènes codant pour la pyruvate décarboxylase de l'hôte Schizosaccharomyces pombe sont délétés ou désactivés. Le transformant selon l'invention est en outre caractérisé en ce que : quand le transformant est inoculé dans 100 ml de milieu liquide dans un flacon Sakaguchi de 500 ml, ledit milieu liquide comp