Oxygen limitations to growaz Adirachta indica cell culture in shake flasks

It was evaluated the growth of Azadirachta indica cell suspension in different conditions of oxygen delivery in Erlenmeyer shake flask. Oxygen transfer rate (OTR, kg O₂ m^-3 day^-1) for the closures utilized were: silicone foam (1.04), cotton (0.58), and aluminum foil (0.07). A. indica cells growing during 6 weeks of subculture showed that lower OTR reduced cell viability, the pH of broth medium, and Azadirachtins production. While, higher OTR induced the formation of aggregates. Using a stirred tank bioreactor, it was determined that A. indica cells had an oxygen consumption of 0.100 kg O₂ kg DW^-1 day^-1, a higher value than other plant cell cultures. These results show that OTR generated in Erlenmeyer shake flasks is lower to oxygen uptake rate of A. indica cells and it is a limiting factor to grow this plant.