Mutant Breeding of Furfural Tolerant Aspergillus terreus for Itaconic Acid Production

Itaconic acid (IA) is one of the most important biobased chemicals, and is generally produced by the filamentous fungi Aspergillus terreus. In order to degrade the production cost of IA, the low-cost and renewable lignocelluloses could be used for IA production. However, inhibitors including furfural derived from indispensable lignocelluloses pretreatment, can seriously hinder the microbial growth and fermentation, and microbial IA production is also no exception. Compared to Saccharomyces cerevisiae, less is known about the effects of furfural for Aspergillus terreus. Here, a furfural tolerant strain was obtained by chemical mutagenesis with diethyl sulfate (DES), and the highest furfural tolerable concentration was up to 1.3 g/L in solid medium. The growth, glucose consumption and IA production of mutant and parental strain were compared in fermentation media containing different furfural concentration, which found 0.5 g/L furfural is the critical concentration. In addition, the morphology of organelle structure was observed with transmission electron microscope and the cellular sugar content was quantified to further support the changes in cell morphology and the impact of furfural.