Efficient itaconic acid production from glycerol with Ustilago vetiveriae TZ1

• Published in: Biotechnology for biofuels 2017-05, Vol.10 (1), p.131-131, Article 131
• Main Authors: Zambanini, Thiemo, Hosseinpour Tehrani, Hamed, Geiser, Elena, Merker, Dorothee, Schleese, Sarah, Krabbe, Judith, Buescher, Joerg M, Meurer, Guido, Wierckx, Nick, Blank, Lars M
• Format: Article
• Language: English
• Subjects: Acid production; Adaptive laboratory evolution; Biodiesel fuels; Biofuels; Biomass; Carbon; Carbon sources; Chemicals; Clusters; Coding; Diesel; Engineering; Evolution; Fed-batch cultivation; Genomes; Glycerol; Itaconate; Itaconic acid; Malate; Metabolism; Microorganisms; Mitochondria; Optimization; Organic acids; Plates; Polymers; Product inhibition; Screening; Transcription; Ustilago vetiveriae
• ISSN: 1754-6834; 1754-6834
• DOI: 10.1186/s13068-017-0809-x

The family of Ustilaginaceae is known for their capability to naturally produce industrially valuable chemicals from different carbon sources. Recently, several Ustilaginaceae were reported to produce organic acids from glycerol, which is the main side stream in biodiesel production. In this study, we present   as new production organism for itaconate synthesis from glycerol. In a screening of 126 Ustilaginaceae, this organism reached one of the highest titers for itaconate combined with a high-glycerol uptake rate. By adaptive laboratory evolution, the production characteristics of this strain could be improved. Further medium optimization with the best single colony,    TZ1, in 24-deep well plates resulted in a maximal itaconate titer of 34.7 ± 2.5 g L produced at a rate of 0.09 ± 0.01 g L  h from 196 g L glycerol. Simultaneously, this strain produced 46.2 ± 1.4 g L malate at a rate of 0.12 ± 0.00 g L  h . Due to product inhibition, the itaconate titer in NaOH-titrated bioreactor cultivations was lower (24 g L ). Notably, an acidic pH value of 5.5 resulted in decreased itaconate production, however, completely abolishing malate production. Overexpression of or , encoding a transcriptional regulator and mitochondrial transporter, respectively, from the itaconate cluster of   resulted in a 2.0-fold ( and 1.5-fold ( ) higher itaconate titer in comparison to the wild-type strain, simultaneously reducing malate production by 75 and 41%, respectively. The observed production properties of    TZ1 make this strain a promising candidate for microbial itaconate production. The outcome of the overexpression experiments, which resulted in reduced malate production in favor of an increased itaconate titer, clearly strengthens its potential for industrial itaconate production from glycerol as major side stream of biodiesel production.