Location: Bioenergy ResearchTitle: Mannose and galactose as substrates for production of itaconic acid by Aspergillus terreus
Submitted to: Letters in Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2017
Publication Date: 10/24/2017
Citation: Saha, B.C., Kennedy, G.J. 2017. Mannose and galactose as substrates for production of itaconic acid by Aspergillus terreus. Letters in Applied Microbiology. 66(6):527-533. https://doi.org/10.1111/lam.12810.
Interpretive Summary: Itaconic acid is a building block platform chemical which is currently produced industrially from glucose by fermentation with a fungus. However, softwood has the potential to serve as low cost source of sugars for production of itaconic acid. In this work, 20 fungal strains were evaluated for production of itaconic acid from softwood derived sugars - mannose and galactose. A novel strain was found that gave the highest itaconic acid titer reported so far from mannose. This is the first detailed report on the production of itaconic acid from mannose and galactose. The results will be very useful in developing a process technology for production of itaconic acid from softwood.
Technical Abstract: 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 oC and 200 rpm for 7 days. Strain NRRL1971 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 liter with a yield of 0.46 g g-1 mannose (highest titer 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 liter 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.