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Open Access Highly Accessed Research

An automated workflow for enhancing microbial bioprocess optimization on a novel microbioreactor platform

Peter Rohe1*, Deepak Venkanna1, Britta Kleine2, Roland Freudl2 and Marco Oldiges1

Author Affiliations

1 Institute of Bio- and Geosciences, IBG-1: Biotechnology, Systems Biotechnology, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany

2 Institute of Bio- and Geosciences, IBG-1: Biotechnology, Systemic Microbiology, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany

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Microbial Cell Factories 2012, 11:144  doi:10.1186/1475-2859-11-144

Published: 31 October 2012

Abstract

Background

High-throughput methods are widely-used for strain screening effectively resulting in binary information regarding high or low productivity. Nevertheless achieving quantitative and scalable parameters for fast bioprocess development is much more challenging, especially for heterologous protein production. Here, the nature of the foreign protein makes it impossible to predict the, e.g. best expression construct, secretion signal peptide, inductor concentration, induction time, temperature and substrate feed rate in fed-batch operation to name only a few. Therefore, a high number of systematic experiments are necessary to elucidate the best conditions for heterologous expression of each new protein of interest.

Results

To increase the throughput in bioprocess development, we used a microtiter plate based cultivation system (Biolector) which was fully integrated into a liquid-handling platform enclosed in laminar airflow housing. This automated cultivation platform was used for optimization of the secretory production of a cutinase from Fusarium solani pisi with Corynebacterium glutamicum. The online monitoring of biomass, dissolved oxygen and pH in each of the microtiter plate wells enables to trigger sampling or dosing events with the pipetting robot used for a reliable selection of best performing cutinase producers. In addition to this, further automated methods like media optimization and induction profiling were developed and validated. All biological and bioprocess parameters were exclusively optimized at microtiter plate scale and showed perfect scalable results to 1 L and 20 L stirred tank bioreactor scale.

Conclusions

The optimization of heterologous protein expression in microbial systems currently requires extensive testing of biological and bioprocess engineering parameters. This can be efficiently boosted by using a microtiter plate cultivation setup embedded into a liquid-handling system, providing more throughput by parallelization and automation. Due to improved statistics by replicate cultivations, automated downstream analysis, and scalable process information, this setup has superior performance compared to standard microtiter plate cultivation.

Keywords:
Microbioreactor; Biolector; Bioprocess development; Strain screening; Heterologous protein expression; Automation; Liquid-handling