Metabolic characterization of a CHO cell size increase phase in fed-batch cultures

• Published in: Applied microbiology and biotechnology 2017-11, Vol.101 (22), p.8101-8113
• Main Authors: Pan, Xiao, Dalm, Ciska, Wijffels, René H., Martens, Dirk E.
• Format: Article
• Language: English
• Subjects: Amino acids; Amino Acids - metabolism; Animals; Antibodies, Monoclonal - biosynthesis; Antibody production; Batch Cell Culture Techniques; Batch culture; Biological research; Biomedical and Life Sciences; Bioreactors; Biosynthesis; Biotechnological Products and Process Engineering; Biotechnology; Cell Cycle - physiology; Cell division; Cell Division - physiology; Cell growth; Cell lines; Cell Proliferation; Cell Size; Cell size increase; Cell Survival; Chinese hamster ovary (CHO) cell; CHO Cells; Cricetulus; Fatty acids; Fatty Acids - metabolism; Fed batch; Glucose - metabolism; Life Sciences; Lipid metabolism; Lipids; Metabolic Flux Analysis; Metabolism; Microbial Genetics and Genomics; Microbiology; Monoclonal antibodies; Phase Transition; Production processes; Stationary phase; Synthesis
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-017-8531-y

Normally, the growth profile of a CHO cell fed-batch process can be divided into two main phases based on changes in cell concentration, being an exponential growth phase and a stationary (non-growth) phase. In this study, an additional phase is observed during which the cell division comes to a halt but the cell growth continues in the form of an increase in cell size. The cell size increase (SI) phase occurs between the exponential proliferation phase (also called the number increase or NI phase) and the stationary phase. During the SI phase, the average volume and dry weight per cell increase threefold linearly with time. The average mAb specific productivity per cell increases linearly with the cell volume and therefore is on average two times higher in the SI phase than in the NI phase. The specific essential amino acids consumption rates per cell remain fairly constant between the NI and the SI phase, which agrees with the similar biomass production rate per cell between these two phases. Accumulation of fatty acids and formation of lipid droplets in the cells are observed during the SI phase, indicating that the fatty acids synthesis rate exceeds the demand for the synthesis of membrane lipids. A metabolic comparison between NI and SI phase shows that the cells with a larger size produce more mAb per unit of O 2 and nutrient consumed, which can be used for further process optimization.