Novel fermentation strategy for enhancing glycerol production by Candida krusei.
During the later stage of glycerol production by fermentation of Candida krusei, glycerol consumption by the strain was observed, although there was residual sugar in the medium. To enhance the final glycerol accumulation, a new fermentation strategy was developed by maintaining high activities of glycerol synthetic enzymes (i.e., glycerol-3-phosphate dehydrogenase (ctGPD) and glycerol-3-phosphatase (GPP)) for a relatively long period while conducting oxygen limitation at a later stage to inhibit the increase of another enzyme activity related to glycerol degradation (i.e., mitochondrial glycerol-3-phosphate dehydrogenase (mtGPD)). With oxygen limitation performed from 88 h, when ctGPD and GPP activities were already at a low level while mtGPD activity was increasing, the glycerol dissimilation was efficiently reduced. The final glycerol concentration reached 55.6 g/L, which was about 18% (96 h) and 30% (104 h) higher than control, and its productivity increased to 0.54 g/(L h). The proposed strategy based on cell physiology was proved useful to the glycerol fermentation process.
Liu
Hong-Juan
HJ
Institute of Applied Chemistry, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
Liu
De-Hua
DH
Zhong
Jian-Jiang
JJ
D019149:Bioreactors / Q000382:microbiology*; D002175:Candida / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D018929:Cell Culture Techniques / Q000379:methods*; D002455:Cell Division / Q000502:physiology; D005947:Glucose / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D010865:Pilot Projects; D011786:Quality Control
D009097:Multienzyme Complexes; D005993:Glycerolphosphate Dehydrogenase; D010744:Phosphoric Monoester Hydrolases; C040842:glycerol-1-phosphatase; D005947:Glucose; D005990:Glycerol; D010100:Oxygen