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

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 Mn2+ 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 PO43− limitation decreased the inhibitory effect of Mn2+ on IA production. In the present study, a novel medium was developed for production of IA by varying PO43−, Fe3+ and Cu2+ concentrations using response surface methodology, which alleviated the strong inhibitory effect of Mn2+. The new medium contained 0.08 g KH2PO4, 3 g NH4NO3, 1 g MgSO4·7H2O, 5 g CaCl2·2 H2O, 0.83 mg FeCl3·6H2O, 8 mg ZnSO4·7H2O, and 45 mg CuSO4·5H2O per liter. The fungus was able to produce IA very well in the presence of Mn2+ up to 100 ppm in the medium. This medium will be extremely useful for IA production in the presence of Mn2+. This is the first report on the development of Mn2+ tolerant medium for IA production by A. terreus. [ABSTRACT FROM AUTHOR]