Screening of feeding strategies based on trigger events in a 24-micro bioreactor platform

Several bioprocesses exploit feeding strategies such as the minimization of acetate production in microbial cell culture. Some of these feeding strategies use values for pH or dissolved oxygen (dO2) as a trigger point. The availability of a platform able to perform this approach on a micro scale cultivation is essential for strain optimization strategy. Applikon’s micro-Matrix product is a platform that holds 24 micro bioreactors (working volume 2-5 mL) with individual control of pH, dO2 and temperature. The micro-Matrix is able to program event-based control whereby the control strategy is based on a triggered event. In the present work, two different feeding strategies in an E. coli cultivation have been implemented based on i) pH above 7.1 and ii) dO2 above 50 %, using the work of Chen et al., 1997 as a reference. The results demonstrate that the micro-Matrix can be successfully used for the screening of different feeding strategies and it is able to reproduce the pH and dO2 profi les observed for a 7 L bioreactor during a pH and DO-stat process.