Clamp System Dual for 2 PreSens SDRs

The yeast P. guillermondii was cultivated in deep well Oxo- and HydroDishes to examine growth profiles and determine the minimal filling volumes for sensor read-out at a shaking speed of 200 rpm. As no optical shielding mask (SDR-OSM24) was used in these experiments, recordings show a higher noise-ratio at lower filling volumes. Both oxygen and pH kinetics show clearly when the initial substrate is consumed and the cultures switch to metabolise another substrate. This substrate change correlates with the filling volume, as low volume samples had better oxygen supply and grew faster, so the initial substrate was used up earlier. The optimal working volume for yeast cultivation in the deep well plates is 1.25 - 1.5 mL. 

Thomas Grimm, BIOWORX, Berlin, Germany

Oxygen kinetics during a shaken E. coli cultivation were monitored using a Deep Well OxoDish®. Different media compositions were tested and compared to a minimal medium (MM). A higher concentration of yeast extract (YE) led to faster growth. Addition of glycerine as a second substrate prolonged the stationary phase. Ammonium chloride had no influence on the metabolism. After the substrate(s) was consumed, oxygen increased due to oxygen ingress.

Olaf Christensen, Lonza Ltd., Visp, Switzerland

Reliable screening set-ups are the key to rapid identification of genetic modifications or changes of cultivation conditions improving strain performance. Using Deep Well SensorDishes® to improve culture conditions for antibody-producing S. cerevisiae strains, it was found that increasing the buffering capacity of standard synthetic yeast media affects the stability of the secreted antibody. Furthermore, it was detected that the media modification also affected dissolved oxygen levels during batch growth of the strain.

l. Kirjavainen and A. Frey, Aalto University, Finland