17-06: Production of itaconic acid from biomass using Ustilago maydis

Itaconic acid (ITA) has been identified by the US DOE as one of the top 12 bio-based chemicals. It is produced at large scale as a building block for various polymers⁽¹⁾, and can also serve as a platform chemical for the production of a wide variety of derivatives, including biofuels.

The most established method of ITA production is by fermentation using 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 a continuous effort to identify alternative ITA production hosts. Ustilago maydis is 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.  Besides the well-studied secretion of glycolipids, U. maydis is also capable of producing ITA⁽²⁾.

Screening of a mutant library of U. maydis overexpressing a putative ITA producing gene (UM06344) led to a significant increase in production. Further improvements can be expected to arise from the characterization of the biochemical ITA production route and improvement of the culture conditions. Furthermore, this organism can grow on the plant polymer xylan, and can metabolize xylose and arabinose. Together, these properties make U. maydis a highly promising host for the production of ITA from lignocellulosic hydrolysates.

(1) M. Okabe et al. Appl Microbiol Biotechnol (2009) 84:597–606

(2) RH. Haskins et al. Can J. Microbiol (1955) 1: 749–756