FACTORS AFFECTING CHINESE HAMSTER OVARY CELL PROLIFERATION AND VIABILITY

Advantageous cultivation procedures for the Chinese hamster ovary (CHO) cells are necessary for the productive commercial production of biopharmaceuticals. A main challenge that needs to be addressed during the process development is the differences in each cell line requirements concerning the nutrients and feed strategies in order to achieve the desired growth characteristics. Therefore, within the current research, a naïve high cell density serum free suspension adapted CHO cell line was tested with glucose and glutamine rich feeds in fed-batch Erlenmeyer shake flask cultures. Glucose consumption rate was adjusted to develop the optimal feed strategies. Obtained results indicated that high glucose and l-glutamine feeding did not improve maximum viable cell density compared to the control samples. During the exponential phase, cell proliferation and viability of all feeds showed no statistically significant difference. Instead, the fed-batch processes tested led to statistically significant differences in viable cell density and cell viability during the decline phase, compared to control (batch) culture. The difference between glucose and glutamine feeding was indistinguishable, most probably due to the concentration imbalance with the rest of the nutrients in feed. The overall study presented a method to slow down the decrease in CHO cell proliferation and viability during the decline phase, instead of increasing the maximum cell density at the plateau phase.

Enzyme-constrained genome-scale metabolic model of Rhodotorula toruloides

Rhodotorula toruloides is a non-conventional, oleaginous yeast able to naturally accumulate high amounts of microbial lipids when grown on various carbon substrates, including from a lignocellulosic origin. Its unique metabolic characteristics, which make lipid synthesis possible, are not fully understood. With genome-scale models (GEMs) it is possible to systematically study cellular metabolism using metabolic flux predictions in silico. Enzyme-constrained genome-scale modelling approach has been demonstrated to improve cell phenotype predictions in model organisms, including yeasts. In this work, enzyme-constrained genome-scale metabolic model of R. toruloides was developed, incorporating cell physiology and absolute proteomics data on three different carbon substrates (xylose, glucose, acetic acid) under exponential growth and lipid accumulation phases. The generated model could predict experimental rates measured in all conditions, except for the gases on glucose. Further, predicted intracellular flux patterns demonstrated the differences in R. toruloides metabolism under different carbon substrates and the importance of cofactor balance (NADPH) during the lipid accumulation. These results and the developed genome-scale model can be further used for the design of efficient microbial cell factories and various metabolic studie

The role of magnetic field in the biopharmaceutical production: Current perspectives

Current scientific evidence on the influence of magnetic field on mammalian cell lines used for industrial production of biopharmaceuticals, on human cell lines and on potential cell lines for the biopharmaceutical production is presented in this review. A novel magnetic coupling induced agitation could be the best solution to eliminate sources of contamination in stirred tank bioreactors which is especially important for mammalian cell cultures. Nevertheless, the side effect of magnetically-coupled stirring mechanism is that cells are exposed to the generated magnetic field. The influence of magnetic field on biological systems has been investigated for several decades. The research continues nowadays as well, investigating the influence of various types of magnetic field in a variety of experimental setups. In the context of bioreactors, only the lower frequencies and intensities of the magnetic field are relevant. Keywords: Time-varying magnetic field, Static magnetic field, Magnetic field influence, Mammalian cells, Biopharmaceutical