HKI Colloquium

Exploiting the biochemical potential of smut fungi for the production of chemicals

Universitätsprofessor Lars M. Blank

RWTH Aachen, Institut für Angewandte Mikrobiologie

Abstract

The envisaged bioeconomy requires efficient whole-cell catalysts for the synthesis of molecules already in use or even novel molecules with advantageous properties. We engineer microbes that can convert renewable resources into valuable chemicals. The followed engineering approach of analysis, design, and synthesis¹ will be presented for the production of organic acids including itaconic and malic acid^2,3.

These acids have been identified by the US DOE as some of the top bio-based chemicals. They are produced at large scale as a building block for various polymers, and can also serve as a platform chemical for the production of a wide variety of derivatives. While malate is produced from crude oil, the established method of itaconate production uses the filamentous fungus Aspergillus terreus. However, the difficulties associated with the submerged fermentation of filamentous fungi in general, and the specific sensitivities of A. terreus to, e.g., substrate impurities, have led to continuous efforts to identify alternative itaconate production hosts.

Alternative organic acid producers belong to the Ustilaginacea, with the most prominent species Ustilago maydis, a basidiomycetous fungus with a highly versatile metabolism. The haploid form of U. maydis has a yeast-like growth pattern and grows readily on defined media. We exploit these so called smut fungi through screening², metabolic engineering³, and process optimization⁴.

The results are presented in the context of the envisaged bioeconomy.