Neurosporaxanthin Overproduction by <i>Fusarium fujikuroi</i> and Evaluation of Its Antioxidant Properties
Neurosporaxanthin (NX) is a carboxylic carotenoid produced by some filamentous fungi, including species of the genera <i>Neurospora</i> and <i>Fusarium</i>. NX biosynthetic genes and their regulation have been thoroughly investigated in <i>Fusarium fujikuroi</i>,...
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| Main Authors: | , , , , , , , , |
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| Format: | Book |
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MDPI AG,
2020-06-01T00:00:00Z.
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| Summary: | Neurosporaxanthin (NX) is a carboxylic carotenoid produced by some filamentous fungi, including species of the genera <i>Neurospora</i> and <i>Fusarium</i>. NX biosynthetic genes and their regulation have been thoroughly investigated in <i>Fusarium fujikuroi</i>, an industrial fungus used for gibberellin production. In this species, carotenoid-overproducing mutants, affected in the regulatory gene <i>carS</i>, exhibit an upregulated expression of the NX pathway. Based on former data on a stimulatory effect of nitrogen starvation on carotenoid biosynthesis, we developed culture conditions with <i>carS</i> mutants allowing the production of deep-pigmented mycelia. With this method, we obtained samples with ca. 8 mg NX/g dry mass, in turn the highest concentration for this carotenoid described so far. NX-rich extracts obtained from these samples were used in parallel with <i>carS</i>-complemented NX-poor extracts obtained under the same conditions, to check the antioxidant properties of this carotenoid in in vitro assays. NX-rich extracts exhibited higher antioxidant capacity than NX-poor extracts, either when considering their quenching activity against [O<sub>2</sub>(<sup>1</sup>Δ<sub>g</sub>)] in organic solvent (singlet oxygen absorption capacity (SOAC) assays) or their scavenging activity against different free radicals in aqueous solution and in liposomes. These results make NX a promising carotenoid as a possible feed or food additive, and encourage further studies on its chemical properties. |
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| Item Description: | 10.3390/antiox9060528 2076-3921 |