Kagoshima University · Division of Agricultural Sciences, School of Agriculture, Fisheries and Veterinary Medicine · 准教授

Research keywords白麹菌・焼酎醸造・クエン酸高生産・Aspergillus luchuensis・Aspergillus chevalieri・麹菌ゲノム編集・有機酸排出トランスポーター・酵母香気成分・分裂酵母ホスホリパーゼ・PCB分解菌

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• Chihiro Kadooka, Shun Yakabe, Daisuke Hira, Taiki Futagami, Masatoshi Goto, Takuji Oka . Functional redundancy and divergence of UDP-glucose 4-epimerases in galactose metabolism and cel2025 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） Galactose-containing polysaccharides in the cell walls of filamentous fungi are vital for hyphal formation, mycelial aggregation, and adhesion. Uridine diphosphate (UDP)-glucose 4-epimerase, an enzyme capable of reversibly converting UDP-glucose to UDP-galactose, plays a key role in galactose metabolism. This study investigates the functional specialization and overlapping roles of UDP-glucose 4-epimerases, UgeA and UgeB, in Aspergillus nidulans. Enzyme activity assays revealed that UgeA catalyzes the interconversion of UDP-glucose and UDP-galactose, while UgeB facilitates both UDP-glucose/UDP-galactose and UDP-N-acetylglucosamine/UDP-N-acetylgalactosamine interconversions. Both UgeA and UgeB successfully restored growth in a yeast gal10 disruptant, indicating their involvement in galactose metabolism in vivo. Additionally, the ugeB disruptant of A. nidulans exhibited growth retardation during galactose metabolism, a defect that was alleviated by complementation with ugeB or multiple-copy expression of ugeA. These findings elucidate the complex interplay between sugar metabolism and cell wall synthesis in filamentous fungi and offer insights for the development of novel antifungal therapies. DOI： 10.1016/j.fgb.2025.103972 PubMed researchmap
• Takefumi Karashima, Ken Oda, Taiki Futagami, Hideki Hokazono, Hideharu Takashita . Ribonucleoprotein-based CRISPR/Cas9 genome co-editing in Aspergillus luchuensis mut. kawachii.2025 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） In this study, we established a ribonucleoprotein-based clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) genome co-editing method for the white koji fungus, Aspergillus luchuensis mut. kawachii. To introduce the single guide RNA-Cas9 ribonucleoprotein complex into protoplast cells of A. luchuensis mut. kawachii, we investigated the conditions for protoplast preparation using Yatalase -Plus-. Subsequently, we employed the ribonucleoprotein-based method to knockout the ATP sulfurylase-encoding sC gene, which imparts selenate resistance in the model strain NBRC 4308 and the industrial strain No. 8046. Furthermore, we explored genome co-editing by simultaneously targeting sC along with either the orotidine 5'-phosphate decarboxylase-encoding pyrG gene or the transcriptional activator of protease genes-encoding prtR gene in NBRC 4308. The transformants were selected in medium containing selenate, resulting in the successful generation of pyrG- and prtR-knockout strains. Similarly, transformants were selected on medium containing selenate, resulting in the successful generation of prtR-knockout strain in No. 8046. These results demonstrate that the ribonucleoprotein-based genome co-editing method is applicable not only to the model strain but also to industrial strains, making it a promising approach for manipulating A. luchuensis mut. kawachii. DOI： 10.1016/j.jbiosc.2025.07.006 PubMed researchmap
• Kazuna Yanagi, Kentaro Hiramatsu, Chihiro Kadooka, Atsushi Nishitani, Kayu Okutsu, Yumiko Yoshizaki, Kazunori Takamine, Hisanori Tamaki, Taiki Futagami . Diverse fungal communities in c2025 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） We investigated the effect of a starter culture on the fungal communities of commercial karebushi. Aspergillus pseudoglaucus was initially identified as the starter fungus. In karebushi samples from two manufacturers relying on naturally occurring molds, Aspergillus chevalieri was the dominant species, accompanied by Aspergillus montevidensis and Aspergillus sydowii, while A. pseudoglaucus was not detected. Among samples from six manufacturers that used the starter culture, A. pseudoglaucus was dominant in only three; in the remaining three, A. chevalieri predominated despite the starter being used. These results suggest that indigenous fungi, particularly A. chevalieri, present in the processing environment can outcompete the starter culture, influence the fungal community, and potentially contribute to the qualitative diversity of karebushi. DOI： 10.2323/jgam.2025.08.001 PubMed researchmap
• Atsushi Nishitani, Kentaro Hiramatsu, Chihiro Kadooka, Kyoka Hiroshima, Kazutaka Sawada, Kayu Okutsu, Yumiko Yoshizaki, Kazunori Takamine, Masatoshi Goto, Hisanori Tamaki, Taiki Futagami .2024 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） The white koji fungus Aspergillus luchuensis mut. kawachii secretes substantial amounts of citric acid through the expression of the citric acid exporter CexA, a member of the DHA1 family. In this study, we aimed to characterize 11 CexA homologs (Chl proteins) encoded in the genome of A. luchuensis mut. kawachii to identify novel transporters useful for organic acid production. We constructed overexpression strains of chl genes using a cexA disruptant of the A. luchuensis mut. kawachii as the host strain, which prevented excessive secretion of citric acid into the culture supernatant. Subsequently, we evaluated the effects of overexpression of chl on producing organic acids by analyzing the culture supernatant. All overexpression strains did not exhibit significant citric acid accumulation in the culture supernatant, indicating that Chl proteins are not responsible for citric acid export. Furthermore, the ChlH overexpression strain displayed an accumulation of 2-oxoglutaric and fumaric acids in the culture supernatant, while the ChlK overexpression strain exhibited the accumulation of 2-oxoglutaric, malic and succinic acids. Notably, the ChlH and ChlK overexpression led to a substantial increase in the production of 2-oxoglutaric acid, reaching approximately 25 mM and 50 mM, respectively. Furthermore, ChlH and ChlK overexpression also significantly increased the secretory production of dicarboxylic acids, including 2-oxoglutaric acid, in the yellow koji fungus, Aspergillus oryzae. Our study demonstrates that overexpression of DHA1 family gene results in enhanced secretion of organic acids in koji fungi of the genus Aspergillus. DOI： 10.1016/j.jbiosc.2024.01.010 PubMed researchmap

• 焼酎酵母の増殖遅延に関連する新規細胞壁合成ネットワークの解明2024 · 配分額： 4680000円 （ 直接経費： 3600000円 、 間接経費： 1080000円 ） researchmap
• 細菌との共培養特異的な麹菌の二次代謝物質生産能発現の分子機構2023 · 配分額： 4680000円 （ 直接経費： 3600000円 、 間接経費： 1080000円 ） researchmap
• 白麹菌の有用物質生産に係る多様な制御機構の解明2022 · 配分額： 17680000円 （ 直接経費： 13600000円 、 間接経費： 4080000円 ） researchmap
• 白麹菌の有用物質生産に係る多様な制御機構の解明2022 · 配分額： 17680000円 （ 直接経費： 13600000円 、 間接経費： 4080000円 ） researchmap

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