PURPOSE: To prepare efficiently S(+)-citramalic acid having high optically purity, by treating mesaconic acid with a specific fungus belonging to the genus Hansenula, etc., collecting the reaction product.
CONSTITUTION: A microorganism [e.g., Hansenula nonfermentans (IFO1473), Kloeckera africana (IFO0633)] belonging to the genus Hansenula or Kloeckera, having mesaconate hydratase activity is used. Namely, the microorganism is aerobically cultivated in a nutritive medium at about 4W9.5pH at about 20W 45°C for about 10W96hr, then treated with mesaconic acid, so that it is converted into S(+)-citramalic acid. Then, the mold is removed from the culture to give a culture solution, which is adjusted to ≤3pH, extracted with ethyl acetate, the extract is purified by chromatography, to give S(+)-citramalic acid.
SAWA IKUO
ASADA MASANORI
WATANABE KIYOSHI
