Precultures grown under fed-batch conditions increase the reliability and reproducibility of high-throughput screening results.

Abstract

One essential task in bioprocess development is strain selection. A common screening procedure consists of three steps: first, the picking of colonies; second, the execution of a batch preculture and main culture e.g. in microtiter plates; and third, the evaluation of product formation. Especially during the picking step, unintended variations occur due to undefined amounts and varying viability of transferred cells. The aim of this study is to demonstrate that the application of polymer-based controlled-release fed-batch microtiter plates during preculture eliminates these variations. The concept of equalizing growth through fed-batch conditions during preculture is theoretically discussed and then tested in a model system, namely, a cellulase-producing E. coli clone bank containing 32 strains. Preculture was once conducted in batch and once in fed-batch mode. By applying fed-batch mode, equalized growth was observed in the subsequent main culture. Furthermore, the standard deviation of cellulase activity was reduced compared to that observed in the conventional approach. Compared with the strains in the batch preculture process, the first-ranked strain in the fed-batch preculture process was the superior cellulase producer. These findings recommend the application of the fed-batch microtiter plate during preculture in high-throughput screening processes to achieve accurate and reliable results. This article is protected by copyright. All rights reserved.