Promoters from the itaconate cluster of Ustilago maydis are induced by nitrogen depletion

Zambanini, Thiemo; Hartmann, Sandra K.; Schmitz, Lisa; Büttner, Linda; Tehrani, Hamed Hosseinpour; Geiser, Elena; Beudels, Melanie Marita; Venc, Dominik; Wandrey, Georg; Büchs, Jochen; Schwarzländer, Markus; Blank, Lars M.; Wierckx, Nick

doi:10.1186/s40694-017-0040-3

Cited by 27 publications

(25 citation statements)

References 62 publications

(82 reference statements)

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“…IA production started after 24 h of growth preceded by an increase in Um_mtt1 expression. Although the relative induction level is different, the expression profile observed here is in agreement with in trans P mtt1 expression analysis using GFP as a reporter [28]. On the other hand, the highest expression of the UMAG02365 and UMAG02806 genes was observed at 24 h during the exponential growth phase and then decreased during the itaconate production phase (stationary phase of growth).…”

Section: Gene Expression Analysis Of Umag02365 and Umag02806 During Isupporting

confidence: 85%

Mitochondrial carriers of Ustilago maydis and Aspergillus terreus involved in itaconate production: same physiological role but different biochemical features

et al. 2019

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Itaconic acid (IA) is a naturally occurring dicarboxylic acid with applications in the manufacture of polymers. IA can be produced by fermentation using the fungi Aspergillus terreus or Ustilago maydis as biocatalysts. Indirect evidence has suggested that the mitochondrial carriers U. maydis Um_Mtt1 and A. terreus At_MttA export mitochondrially synthesized cis‐aconitate to the cytosol for IA synthesis using malate as a countersubstrate. Here, by assaying the transport features of recombinant Um_Mtt1 and At_MttA in reconstituted liposomes, we find that both proteins efficiently transport cis‐aconitate, but malate is well transported only by Um_Mtt1 and 2‐oxoglutarate only by At_MttA. Bioinformatic analysis shows that Um_Mtt1 and At_MttA form a distinctive mitochondrial carrier subfamily. Our data show that although fulfilling the same physiological task, Um_Mtt1 and At_MttA have different biochemical features.

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Section: Gene Expression Analysis Of Umag02365 and Umag02806 During Isupporting

confidence: 85%

Mitochondrial carriers of Ustilago maydis and Aspergillus terreus involved in itaconate production: same physiological role but different biochemical features

et al. 2019

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“…The mineral medium described by Geiser et al [22] was adapted for the cultivation on pectic substrates. Nitrogen limitation is known to induce itaconic acid production in certain U. maydis strains, but significantly reduces growth [3, 51–53]. As this study focuses on the growth on complex substrates, the ammonium chloride concentration was elevated from 0.8 to 4.0 g/L to prevent a secondary substrate limitation.…”

Section: Resultsmentioning

confidence: 99%

Online evaluation of the metabolic activity of Ustilago maydis on (poly)galacturonic acid

et al. 2018

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BackgroundPectin is a rather complex and highly branched polysaccharide strengthening the plant cell wall. Thus, many different pectinases are required for an efficient microbial conversion of biomass waste streams with a high pectin content like citrus peel, apple pomace or sugar beet pulp. The screening and optimization of strains growing on pectic substrates requires both, quantification of the residual substrate and an accurate determination of the enzymatic activity. Galacturonic acid, the main sugar unit of pectin, is an uncommon substrate for microbial fermentations. Thus, growth and enzyme production of the applied strain has to be characterized in detail to understand the microbial system. An essential step to reach this goal is the development of online monitoring tools.ResultsIn this study, a method for the online determination of residual substrate was developed for the growth of the plant pathogenic fungus Ustilago maydis on pectic substrates such as galacturonic acid. To this end, an U. maydis strain was used that expressed a heterologous exo-polygalacturonase for growth on polygalacturonic acid. The growth behavior on galacturonic acid was analyzed by online measurement of the respiration activity. A method for the online prediction of the residual galacturonic acid concentration during the cultivation, based on the overall oxygen consumption, was developed and verified by offline sampling. This sensitive method was extended towards polygalacturonic acid, which is challenging to quantify via offline measurements. Finally, the enzymatic activity in the culture supernatant was calculated and the enzyme stability during the course of the cultivation was confirmed.ConclusionThe introduced method can reliably predict the residual (poly)galacturonic acid concentration based on the overall oxygen consumption. Based on this method, the enzymatic activity of the culture broth of an U. maydis strain expressing a heterologous exo-polygalacturonase could be calculated. It was demonstrated that the method is especially advantageous for determination of low enzymatic activities. In future, it will be applied to U. maydis strains in which the number of produced hydrolytic enzymes is increased for more efficient degradation.Electronic supplementary materialThe online version of this article (10.1186/s13036-018-0128-1) contains supplementary material, which is available to authorized users.

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“…That said, certain stresses can induce filamentous growth in U. maydis [45, 54] but efficient itaconate production with this species is, at least at small scale, not coupled to a specific morphology. In wild-type U. maydis , itaconate production is induced by nitrogen limitation [74] and requires pH values above five [21]. Like in A. terreus , the genes encoding the itaconate production pathway in U. maydis are clustered and co-regulated [19, 53].…”

Section: Introductionmentioning

confidence: 99%

Integrated strain- and process design enable production of 220 g L−1 itaconic acid with Ustilago maydis

Tehrani

Becker

Bator

et al. 2019

Biotechnol Biofuels

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BackgroundItaconic acid is an unsaturated, dicarboxylic acid which finds a wide range of applications in the polymer industry and as a building block for fuels, solvents and pharmaceuticals. Currently, Aspergillus terreus is used for industrial production, with titers above 100 g L−1 depending on the conditions. Besides A. terreus, Ustilago maydis is also a promising itaconic acid production host due to its yeast-like morphology. Recent strain engineering efforts significantly increased the yield, titer and rate of production.ResultsIn this study, itaconate production by U. maydis was further increased by integrated strain- and process engineering. Next-generation itaconate hyper-producing strains were generated using CRISPR/Cas9 and FLP/FRT genome editing tools for gene deletion, promoter replacement, and overexpression of genes. The handling and morphology of this engineered strain were improved by deletion of fuz7, which is part of a regulatory cascade that governs morphology and pathogenicity. These strain modifications enabled the development of an efficient fermentation process with in situ product crystallization with CaCO3. This integrated approach resulted in a maximum itaconate titer of 220 g L−1, with a total acid titer of 248 g L−1, which is a significant improvement compared to best published itaconate titers reached with U. maydis and with A. terreus.ConclusionIn this study, itaconic acid production could be enhanced significantly by morphological- and metabolic engineering in combination with process development, yielding the highest titer reported with any microorganism.

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Promoters from the itaconate cluster of Ustilago maydis are induced by nitrogen depletion

Cited by 27 publications

References 62 publications

Mitochondrial carriers of Ustilago maydis and Aspergillus terreus involved in itaconate production: same physiological role but different biochemical features

Mitochondrial carriers of Ustilago maydis and Aspergillus terreus involved in itaconate production: same physiological role but different biochemical features

Online evaluation of the metabolic activity of Ustilago maydis on (poly)galacturonic acid

Integrated strain- and process design enable production of 220 g L−1 itaconic acid with Ustilago maydis

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