Shaanxi R&D Center of Biomaterials and Fermentation Engineering, School of Chemical Engineering, Northwest University, Xi'an 710069, People's Republic of China.
Biotechnol Appl Biochem. 2010 Mar 19;55(4):169-74. doi: 10.1042/BA20090314.
The effects of different methods for elevating the OTR (oxygen transfer rate) during foreign gene expression and the cell growth of recombinant Escherichia coli BL21 were investigated. Two strategies were introduced to control DO (dissolved oxygen) levels in the fermentation broth: (i) increasing fermentor pressure and (ii) supplying oxygen-enriched air. These two methods were compared with the glucose feedback model, which acted as the control. By adopting a fed-batch method of cultivation, the cell yield coefficient (YX/S), accumulation of acetic acid and volumetric product yield (Yp) were measured or estimated. Adoption of these two methods led to an improvement in the OTR. The cell density and volumetric product yield in the cultivation controlled by increasing the fermentor pressure reached 77 g x l(-1) (dry cell weight) and 14 g x l(-1) respectively, which were much higher than those obtained with the strategy of supplying oxygen-enriched air (48 and 6 g x l(-1) respectively) and in the control (46 and 7 g x l(-1) respectively). The results indicate that increasing fermentor pressure is an effective way to enhance the OTR and recombinant protein (human-like collagen) productivity.
研究了不同方法提高外源基因表达和重组大肠杆菌 BL21 细胞生长过程中的 OTR（氧传递速率）的效果。引入了两种策略来控制发酵液中的 DO（溶解氧）水平：（i）增加发酵罐压力和（ii）供应富氧空气。这两种方法与葡萄糖反馈模型进行了比较，后者作为对照。通过采用分批补料培养方法，测量或估计了细胞产率系数（YX/S）、乙酸积累和比体积产物产率（Yp）。采用这两种方法提高了 OTR。通过增加发酵罐压力控制的培养物中的细胞密度和比体积产物产率分别达到 77 g x l(-1)（干细胞重量）和 14 g x l(-1)，明显高于供应富氧空气策略（分别为 48 和 6 g x l(-1)）和对照（分别为 46 和 7 g x l(-1)）。结果表明，增加发酵罐压力是提高 OTR 和重组蛋白（类人胶原蛋白）产率的有效方法。
