This raises demand for scalable tools for diligent analysis of recombinant strains in order to evaluate their potential as cell factories and to guide further developments.
To meet the demand for a fast and reliable method for physiological characterisation of fungal strains, a fully automated screening approach using a microtiter format was developed. This method aimed at characterising physiology at two levels:
1) An approach focusing on the traditional growth related parameters i.e. growth rate, yield coefficients and extracellular metabolites.
2) 13C-labelling experiments, where metabolic fluxes are quantified in the strains of interest during exponential growth.
The novelty of this approach is the potential for early selection of potential cell factories based on their growth rates, metabolic capacity for producing products of interest and further characterised based on their flux distributions. As a validation of the setup well characterised fungal strains were selected and tested using the described method supported by tests on recombinant strains producing metabolites of interest. The scalability of the methodology was challenged in sequences of scale-up experiments with the well characterised CEN.PK113-7D strain and substantiated through metabolic flux analysis in both microtiter format and in bioreactors.
This highly versatile approach in terms of scalability, offers the attractive possibility for up-scaling directly from screening levels to volumes designed for product production in a reliable high throughput setting.