[The key enzymes of metabolisms of glycerol in Candida glycerolgenesis].
The specific enzymes for glycerol formation and dissimilation in Candida glycerolgenesis were studied. C. glycerolgenesis hardly assimilated glycerol without glucose and a little amount of glucose remarkably stimulated this dissimilation pathway and the activity and expression of mitochondrial glycerol-3-phosphate dehydrogenase was induced strongly by glycerol-3-phosphate and repressed by glucose metabolism. During glycerol production fermented by C. glycerolgenesis, the activity of cytoplasmic glycerol 3-phosphate dehydrogenase maintained at a higher level and existed two peaks of activity, which appeared at 36 h and 60 h, respectively. The activity level of the first activity peak determines glycerol productivity and becomes a key enzyme of glycerol formation. The activity of glycerol 3-phosphatase maintained at a higher level just between 18 h and 48 h and appeared on peak activity at 36 h. In that period, the activity of glycerol 3-phosphatase was up to more than two times of cytoplasmic glycerol 3-phosphate dehydrogenase and that was inosculated with the phase of rapid accumulation of glycerol during glycerol production by C. glycerolgenesis. In the phase of slowly accumulation of glycerol between 48 h and 72 h, the activity of glycerol 3-phosphatase decreased below that of cytoplasmic glycerol 3-phosphate dehydrogenase. So, cytoplasmic glycerol 3-phosphate dehydrogenase is a key enzyme of glycerol formation in the phase of rapid accumulation of glycerol and glycerol 3-phosphatase becomes a more effective factor after glycerol fermentation reached into slowly accumulation phase. In a conclusion, it is a fundamental for C. glycerolgenesis over-producing high level of glycerol that its cytoplasmic glycerol 3-phosphate dehydrogenase maintains at high activity and the activity of glycerol 3-phosphatase is much higher than that of cytoplasmic glycerol 3-phosphate dehydrogenase.