Characteristics of High-cell Density Cultivation of Recombinant Escherichia coli Producing RHLC Using the Fermentor Pressure Shifting Strategy

• Published in: Biotechnology and bioprocess engineering 2011, 16(3), , pp.488-494
• Main Authors: Chi, Lei, Northwest University, Xi'an, China, Fan, Dai-Di, Northwest University, Xi'an, China, Ma, Xiao-Xuan, Northwest University, Xi'an, China, Luo, Yan-E, Northwest University, Xi'an, China, Zhu, Chen-Hui, Northwest University, Xi'an, China
• Format: Article
• Language: English
• Subjects: ESCHERICHIA COLI; fermentor pressure; kinetic model; oxygen transfer capacity; recombinant Escherichia coli; recombinant human-like collagen; 생물공학
• ISSN: 1226-8372; 1976-3816

To increase the biomass and production of recombinant human-like collagen (RHLC), the effect of controlled fermentor pressure during fed-batch cultivation was investigated using recombinant Escherichia coli producing RHLC. This study focused primarily on the effects of the fermentor pressure on the oxygen transfer capacity. A twostep exponential feeding strategy was used to control the specific growth rate at 0.2 and 0.1/h in the fed-batch and induction phase, respectively. A kinetic model of cell growth was developed, and the specific growth rate, specific glucose uptake rate, concentration of extracellular DNA, and percentage of plasmid loss were calculated and detected. The results demonstrated that increasing the fermentor pressure was an effective way of avoiding the oxygen transfer capacity limitation, and an increase in the dissolved CO₂ content did not affect the growth of the recombinant E. coli BL21 strain. At the end of the fermentation process, the cell density (represented by the dry cell weight, DCW) reached 77.3 g/L, and the RHLC concentration reached 14.1 g/L. In addition, the oxygen transfer capacity (K∧LaC*) decreased drastically at approximately 5 h after induction. This is probably because of the increased concentration of extracellular DNA due to cell lysis, indicating that the cells needed to be harvested.