CONTINUOUS PRODUCTION OF S-LACTOYLGLUTATHIONE BY IMMOBILIZED GLYOXALASE-I FROM HANSENULA-MRAKII

S-Lactoylglutathione is synthesized from methylglyoxal and glutathione by the action of glyoxalase I. Partially purified glyoxalase I from a yeast, Hansenula mrakii IFO 0895, was immobilized to silica gel and DEAE-cellulose, respectively, and some properties of these immobilized enzymes for the production of S-lactoylglutathione were studied. The optimal pH for the activity of glyoxalase I immobilized to DEAE-cellulose was around the acidic region (pH 5-6), whereas that of the enzyme immobilized to the silica gel was shifted to the alkaline region (pH 8-9). The silica gel-immobilized enzyme showed higher stability during the storage than the DEAE-cellulose-immobilized enzyme. By packing the immobilized enzyme into a column, the continuous production of S-lactoylglutathione was investigated. Approximately 30 g/l (83 mM) of S-lactoylglutathione could be produced from 100 mM methylglyoxal and 100 mM glutathione by using the glyoxalase I immobilized to silica gel when the space velocity was fixed at 0.025 min-1.