Efficient itaconic acid production by Aspergillus terreus: Overcoming the strong inhibitory effect of manganese

Abstract Itaconic acid (IA), a building block platform chemical, is produced industrially by Aspergillus terreus utilizing glucose. Lignocellulosic biomass can serve as a low cost source of sugars for IA production. However, the fungus could not produce IA from dilute acid pretreated and enzymatically saccharified wheat straw hydrolyzate even at 100‐fold dilution. Furfural, hydroxymethyl furfural and acetic acid were inhibitory, as is typical, but Mn 2+ was particularly problematic for IA production. It was present in the hydrolyzate at a level that was 230 times over the inhibitory limit (50 ppb). Recently, it was found that PO 4 3− limitation decreased the inhibitory effect of Mn 2+ on IA production. In the present study, a novel medium was developed for production of IA by varying PO 4 3− , Fe 3+ and Cu 2+ concentrations using response surface methodology, which alleviated the strong inhibitory effect of Mn 2+ . The new medium contained 0.08 g KH 2 PO 4 , 3 g NH 4 NO 3 , 1 g MgSO 4 ·7H 2 O, 5 g CaCl 2 ·2 H 2 O, 0.83 mg FeCl 3 ·6H 2 O, 8 mg ZnSO 4 ·7H 2 O, and 45 mg CuSO 4 ·5H 2 O per liter. The fungus was able to produce IA very well in the presence of Mn 2+ up to 100 ppm in the medium. This medium will be extremely useful for IA production in the presence of Mn 2+ . This is the first report on the development of Mn 2+ tolerant medium for IA production by A. terreus .