Liu Hong-Juan, Liu De-Hua, Zhong Jian-Jiang
Institute of Applied Chemistry, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
Biotechnol Prog. 2003 Sep-Oct;19(5):1615-9. doi: 10.1021/bp034097f.
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.
在克鲁斯假丝酵母发酵生产甘油的后期，尽管培养基中仍有残余糖分，但观察到该菌株会消耗甘油。为提高最终甘油积累量，开发了一种新的发酵策略，即在相对较长时间内维持甘油合成酶（即甘油-3-磷酸脱氢酶（ctGPD）和甘油-3-磷酸酶（GPP））的高活性，同时在后期进行限氧以抑制与甘油降解相关的另一种酶活性（即线粒体甘油-3-磷酸脱氢酶（mtGPD））的增加。从88小时开始进行限氧，此时ctGPD和GPP活性已处于较低水平而mtGPD活性正在增加，甘油异化作用得到有效降低。最终甘油浓度达到55.6 g/L，比对照分别高出约18%（96小时）和30%（104小时），其生产率提高到0.54 g/(L·h)。所提出的基于细胞生理学的策略被证明对甘油发酵过程是有用的。
