Mannose and galactose as substrates for production of itaconic acid by Aspergillus terreus

Itaconic acid (IA), an unsaturated 5-carbon dicarboxylic acid, is a building block platform chemical that is currently produced industrially from glucose by fermentation with Aspergillus terreus. Softwood has the potential to serve as low cost source of sugars for its production. Effective utilization of all softwood derived sugars such as glucose, mannose and galactose by the fungus for production of IA will lower the cost of its production. In this work, 20 A. terreus strains were evaluated for the first time for IA production from mannose and galactose in shake-flasks at initial pH of 3·1, 33°C and 200 rev min^-1 for 7 days. Strain NRRL 1971 possesses the unique ability to produce high concentrations of IA from mannose. It produced 36·4 ± 0·2 g IA from 80 g mannose per litre with a yield of 0·46 g g^-1 mannose (highest titre reported so far). This strain has the potential to be used for IA production from softwood. The maximum (1·1 ± 0·2 g) IA was produced by strain DSM 23081 from 80 g galactose per litre utilizing only 9·1 ± 0·3 g. Galactose was not suitable for IA production by these strains. This is the first detailed report on the production of IA from mannose and galactose.

Itaconic acid (IA) is a building block platform chemical which is currently produced industrially from glucose by fermentation with Aspergillus terreus. In order to expand the use of IA, its production cost must be lowered. Softwood has the potential to serve as low cost source of sugars for its production. In this work, 20 A. terreus strains were evaluated for the first time for production of IA from mannose and galactose, sugars derived from softwood. A novel strain was found that gave the highest IA titre reported so far. Galactose was a poor substrate for IA production by A. terreus.