Dissolved carbon dioxide (pCO_{2) has been identified as an important process parameter affecting cell growth, productivity and product quality (e.g. glycosylation) of recombinant proteins when exceeding critical levels, occurring especially in industrial large-scale cell culture processes due to the increased hydrostatic pressure. As CO_{2can easily pass the cellular membrane and thereby influence intracellular pH (pH_{i), important cellular processes (e.g. cell cycle regulation, enzymes of TCA cycle) are directly influenced by pCO_{2and dependent bicarbonate concentration. Consequently, process control strategies attend to keep pCO_{2within physiological range. In a metabolic engineering approach an antibody producing CHO cell line stably expressing human carbonic anhydrase (hCAII), the enzyme that catalyzes the equilibrium of CO_{2in aqueous solutions, was generated and used to characterize CO_{2effects in simulated CO_{2acid load and high CO_{2levels as they occur in large scale mammalian cell culture. The cell line expressing active hCAII showed more rapid initial re-alkalinization of cytoplasm after induced CO_{2acid load. Results also suggest that cellular pH_{ifine tuning was performed by the Cl^{-/HCO_{3^{-exchanger (AE) and Na--dependent Cl^{-/HCO_{3^{-exchanger (NCBE) instead of the Na^{+/H^{+exchanger (NHE1). weiterlesen