Phosphate limitation alleviates the inhibitory effect of manganese on itaconic acid production by Aspergillus terreus

Lignocellulosic biomass has the potential to serve as a low-cost source of sugars for production of itaconic acid (IA, a building block platform chemical) by fermentation with Aspergillus terreus. However, the IA production from biomass hydrolysate was severely inhibited. Mn2+ was found to inhibit the IA production strongly. The effect of Mn2+ on each medium component (KH2PO4, NH4NO3, MgSO4 center dot 7H(2)O, CaCl2 center dot 2H(2)O, FeCl3 center dot 6H(2)O, ZnSO4 center dot 7H(2)O, and CuSO4 center dot 7H(2)O) was evaluated for sugar utilization and IA production by A. terreus NRRL 1972. Both K+ and PO4-3 were necessary for IA production. Low PO4-3 in the medium greatly alleviated the inhibitory effect of Mn2+ on IA production. However, high PO4-3 (K+) was detrimental for IA production in the presence of Mn2+. The inhibitory effect of Mn2+ on IA production was partly eliminated by increasing the CuSO4 center dot 7H(2)O level in the medium. This is the first report on the effect of phosphate limitation to alleviate the inhibition of IA production by Mn2+ and on the relationship of Mn(2+)on the medium components for utilization of sugar and production of IA.