Abstract
The family Ustilaginaceae (belonging to the smut fungi) are known for their plant pathogenicity. Despite the fact that these plant diseases cause agricultural yield reduction, smut fungi attracted special attention in the field of industrial biotechnology. Ustilaginaceae show a versatile product spectrum such as organic acids (e.g., itaconate, malate, succinate), polyols (e.g., erythritol, mannitol), and extracellular glycolipids, which are considered value-added chemicals with potential applications in the pharmaceutical, food, and chemical industries. This study focused on itaconate as a platform chemical for the production of resins, plastics, adhesives, and biofuels. During this work, 72 different Ustilaginaceae strains from 36 species were investigated for their ability to (co-) consume the CO2-derived substrates acetate and formate, potentially contributing toward a carbon-neutral itaconate production. The fungal growth and product spectrum with special interest in itaconate was characterized. Ustilago maydis MB215 and Ustilago rabenhorstiana NBRC 8995 were identified as promising candidates for acetate metabolization whereas Ustilago cynodontis NBRC 7530 was identified as a potential production host using formate as a co-substrate enhancing the itaconate production. Selected strains with the best itaconate production were characterized in more detail in controlled-batch bioreactor experiments confirming the co-substrate utilization. Thus, a proof-of-principle study was performed resulting in the identification and characterization of three promising Ustilaginaceae biocatalyst candidates for carbon-neutral itaconate production contributing to the biotechnological relevance of Ustilaginaceae.
Highlights
Itaconic acid is an unsaturated dicarboxylic acid that shows a broad application spectrum due to its two functional groups
Besides A. terreus, other microorganisms have been reported as natural itaconate producers such as yeasts belonging to Candida species, smut fungi belonging to the family of Ustilaginaceae such as the pH tolerant U. cynodontis, and the yeast-like Ustilago maydis, which have recently been engineered to higher efficiency [15,16,17,18]
For the identification of promising biocatalysts contributing to a CO2 -neutral synthesis of itaconic acid, 72 different Ustilaginaceae strains of 36 species in total were cultivated and screened for growth on acetate and formate as potential co-substrates derived from
Summary
Itaconic acid is an unsaturated dicarboxylic acid that shows a broad application spectrum due to its two functional groups. Since the 1950s, industrial biotechnological production of itaconate has been performed by the filamentous fungus Aspergillus terreus. This long production and optimization history has enabled titers in a range of 85–100 g L−1 and yields near the theoretical maximum at low pH, making A. terreus, so far, the best industrial production host for itaconate [10,11,12]. Microbial itaconate production using this fungus remains challenging. It shows a production dependent on a certain morphology which is required for its high productivity leading to an increase of the production costs [13,14]. Besides A. terreus, other microorganisms have been reported as natural itaconate producers such as yeasts belonging to Candida species, smut fungi belonging to the family of Ustilaginaceae such as the pH tolerant U. cynodontis, and the yeast-like Ustilago maydis, which have recently been engineered to higher efficiency [15,16,17,18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
