A minimal growth medium for the basidiomycete for metabolic flux analysis.

BACKGROUND

secretes a huge enzymatic repertoire including hydrolytic and oxidative enzymes and is an example for higher basidiomycetes being interesting for biotechnology. The complex growth media used for submerged cultivation limit basic physiological analyses of this group of organisms. Using undefined growth media, only little insights into the operation of central carbon metabolism and biomass formation, , the interplay of catabolic and anabolic pathways, can be gained.

RESULTS

The development of a chemically defined growth medium allowed rapid growth of in submerged cultures. As grew extremely slow in salt medium, the co-utilization of amino acids using C-labelled glucose was investigated by gas chromatography-mass spectrometry (GC-MS) analysis. While some amino acids were synthesized up to 90% from glucose ( alanine), asparagine and/or aspartate were predominantly taken up from the medium. With this information in hand, a defined yeast free salt medium containing aspartate and ammonium nitrate as a nitrogen source was developed. The observed growth rates of were well comparable with those previously published for complex media. Importantly, fast growth could be observed for 4 days at least, up to cell wet weights (CWW) of 400 g L. The chemically defined medium was used to carry out a C-based metabolic flux analysis, and the reactions rates in the central carbon metabolism of were investigated. The results revealed a highly respiratory metabolism with high fluxes through the pentose phosphate pathway and TCA cycle.

CONCLUSIONS

The presented chemically defined growth medium enables researchers to study the metabolism of , significantly enlarging the analytical capabilities. Detailed studies on the production of extracellular enzymes and of secondary metabolites of may be designed based on the reported data.