DEVELOPMENT OF AN ONLINE CONTROL-SYSTEM FOR THE CULTIVATION OF ANIMAL-CELLS IN A HOLLOW-FIBER REACTOR USING FLOW-INJECTION ANALYSIS AND A VISUAL PROGRAMMING LANGUAGE

A system for the independent control of ammonia and glutamine in a hol low-fiber reactor has been developed. On-line analysis of the two chem ical species was performed using FIA. A custom-made program has been w ritten to fully automate the FIA, to perform measurements, calibration s and data acquisition, and to activate two peristaltic feed pumps. Di agnostic tests were also automatically performed in order to identify, and in some cases eliminate, erroneous measurements and calibrations due to instrument failures. For this purpose, a visual programming lan guage (LabVIEW) has been chosen. Ammonia concentration was controlled by varying the medium supply rate to the hollow-fiber reactor, which w as shown to behave like an ideal-stirred tank reactor. The glutamine c oncentration was controlled through the intermittent activation of a p ump delivering a concentrated solution of this species to the reactor. This control system was tested with a culture of hybridoma cells at t hree different ammonia and one glutamine set-points. The hollow-fiber reactor was successfully operated automatically for more than 1200 h w ith ammonia and glutamine concentrations accurately controlled at non- limiting levels. The visual programming environment was found to be re liable and highly suitable for the development of custom programs for bioprocess control.