Submitted to: Applied Biochemistry and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2018
Publication Date: 7/4/2018
Citation: Saha, B.C., Kennedy, G.J., Bowman, M.J., Qureshi, N., Dunn, R.O. 2018. Factors affecting production of itaconic acid from mixed sugars by Aspergillus terreus. Applied Biochemistry and Biotechnology. 187(2):449-460. https://doi.org/10.1007/s12010-018-2831-2
DOI: https://doi.org/10.1007/s12010-018-2831-2

Interpretive Summary: Itaconic acid is a building block platform chemical which is currently produced industrially from glucose by fermentation with a fungus. Biomass has the potential to serve as low cost source of sugars for itaconic acid production. However, the fungus could not produce itaconic acid from hydrolyzed biomass. In this work, the factors responsible for inhibition of itaconic acid production were investigated. The results will be very useful in developing process technology for itaconic acid production from biomass by the fungus.

Technical Abstract: Itaconic acid (IA; a building block platform chemical) is currently produced industrially from glucose by fermentation with Aspergillus terreus. In order to expand the use of IA, its production cost must be lowered. Lignocellulosic biomass has the potential to serve as low-cost source of sugars for IA production. It was found that the fungus cannot produce IA from dilute acid pretreated and enzymatically saccharified wheat straw hydrolysate even at 100-fold dilution. The effects of typical compounds (acetic acid, furfural, HMF and Mn2+, enzymes, CaSO4), culture conditions (initial pH, temperature, aeration), and medium components (KH2PO4, NH4NO3, CaCl2·2H2O, FeCl3·6H2O) on growth and IA production by A. terreus NRRL 1972 using mixed sugar substrate containing glucose, xylose, and arabinose (4:3:1, 80 g L-1) mimicking the wheat straw hydrolysate were investigated. Acetic acid, furfural, Mn2+, and enzymes were strong inhibitors to both growth and IA production from mixed sugars. Optimum culture conditions (pH 3.1, 33 °C, 200 rpm) and medium components (0.8 g KH2PO4, 3 g NH4NO3, 2.0 g CaCl2·2H2O, 0.83–3.33 mg FeCl3·6H2O per L) as well as tolerable levels of inhibitors (0.4 g acetic acid, <'0.1 g furfural, 100 mg HMF, <'5.0 ppb Mn2+, 24 mg CaSO4 per L) for mixed sugar utilization were established. The results will be highly useful for developing a bioprocess technology for IA production from lignocellulosic feedstocks.