研究者詳細 - 二神　泰基

論文 - 二神　泰基

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Enkang Zhu, Kentaro Hiramatsu, Taiga Inoue, Kazuki Mori, Kosuke Tashiro, Kiyotaka Fujita, Takefumi Karashima, Hideharu Takashita, Kayu Okutsu, Yumiko Yoshizaki, Kazunori Takamine, Hisanori Tamaki, Taiki Futagami . Deficiency of β-xylosidase activity in Aspergillus luchuensis mut. kawachii IFO 4308. . Bioscience, biotechnology, and biochemistry 2024年4月国際誌

記述言語：英語掲載種別：研究論文（学術雑誌）

In this study, we investigated a deleterious mutation in the β-xylosidase gene, xylA (AkxylA), in Aspergillus luchuensis mut. kawachii IFO 4308 by constructing an AkxylA disruptant and complementation strains of AkxylA and xylA derived from A. luchuensis RIB2604 (AlxylA), which does not harbor the mutation in xylA. Only the AlxylA complementation strain exhibited significantly higher growth and substantial β-xylosidase activity in medium containing xylan, accompanied by an increase in XylA expression. This resulted in lower xylobiose and higher xylose concentrations in the mash of barley shochu. These findings suggest that the mutation in xylA affects xylose level during the fermentation process. Because the mutation in xylA was identified not only in the genome of strain IFO 4308 but also the genomes of other industrial strains of A. luchuensis and A. luchuensis mut. kawachii, these findings enhance our understanding of the genetic factors that affect the fermentation characteristics.

DOI： 10.1093/bbb/zbae046

Atsushi Nishitani, Kentaro Hiramatsu, Chihiro Kadooka, Kyoka Hiroshima, Kazutaka Sawada, Kayu Okutsu, Yumiko Yoshizaki, Kazunori Takamine, Masatoshi Goto, Hisanori Tamaki, Taiki Futagami . Overexpression of the DHA1 family, ChlH and ChlK, leads to enhanced dicarboxylic acids production in koji fungi, Aspergillus luchuensis mut. kawachii and Aspergillus oryzae. . Journal of bioscience and bioengineering 2024年2月

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

Yuki Kobashi, Eri Nakayama, Naoki Fukumori, Ayane Shimojima, Manami Tabira, Yuki Nishimura, Manami Mukae, Ai Muto, Naoto Nakashima, Kayu Okutsu, Yumiko Yoshizaki, Taiki Futagami, Kazunori Takamine, Hisanori Tamaki . Homozygous gene disruption in diploid yeast through a single transformation. . Journal of bioscience and bioengineering137 ( 1 ) 31 - 37 2024年1月

記述言語：英語掲載種別：研究論文（学術雑誌）

As industrial shochu yeast is a diploid strain, obtaining a strain with mutations in both allelic genes was considered difficult. We investigated a method for disrupting two copies of a homozygous gene with a single transformation. We designed a disruption cassette containing an intact LYS5 flanked by nonfunctional ura3 gene fragments divided into the 5'- and 3'-regions. These fragments had overlapping sequences that enabled LYS5 removal as well as URA3 regeneration through loop-out. Furthermore, both ends of the disruption cassette had an additional repeat sequence that allowed the cassette to be removed from the chromosome through loop-out. First, 45 bases of 5'- and 3'-regions of target gene sequences were added on both ends of this cassette using polymerase chain reaction; the resultant disruption cassette was introduced into a shochu yeast strain (ura3/ura3 lys5/lys5); then, single allele disrupted strains were selected on Lys drop-out plates; and after cultivation in YPD medium, double-disrupted strains, in which replacement of another allelic gene with disruption cassette by loss of heterozygosity and regeneration of URA3 in one of the cassettes by loop-out, were obtained by selection on Ura and Lys drop-out plates. The disruption cassettes were removed from the double-disrupted strain via loop-out between repeat sequences in the disruption cassette. The strains that lost either URA3 or LYS5 were counter-selected on 5-fluoroorotic acid or α-amino adipic acid plates, respectively. Using this method, we obtained leu2/leu2 and leu2/leu2 his3/his3 strains in shochu yeast, demonstrating the effectiveness and repeatability of this gene disruption technique in diploid yeast Saccharomyces cerevisiae.

DOI： 10.1016/j.jbiosc.2023.11.003

Yuki Kobashi, Yumiko Yoshizaki, Kayu Okutsu, Taiki Futagami, Hisanori Tamaki, Kazunori Takamine . THI3 contributes to isoamyl alcohol biosynthesis through thiamine diphosphate homeostasis. . Journal of bioscience and bioengineering 2023年12月

記述言語：英語掲載種別：研究論文（学術雑誌）

Isoamyl alcohol is a precursor of isoamyl acetate, an aromatic compound that imparts the ginjo aroma to sake. The isoamyl alcohol biosynthesis pathway in yeasts involves the genes PDC1, PDC5, PDC6, ARO10, and THI3 encoding enzymes that decarboxylate α-ketoisocaproic acid to isovaleraldehyde. Among these genes, THI3 is the main gene involved in isoamyl alcohol biosynthesis. Decreased production of isoamyl alcohol has been reported in yeast strains with disrupted THI3 (Δthi3). However, it has also been reported that high THI3 expression did not enhance decarboxylase activity. Therefore, the involvement of THI3 in isoamyl alcohol biosynthesis remains unclear. In this study, we investigated the role of THI3 in isoamyl alcohol biosynthesis. While reproducing previous reports of reduced isoamyl alcohol production by the Δthi3 strain, we observed that the decrease in isoamyl alcohol production occurred only at low yeast nitrogen base concentrations in the medium. Upon investigating individual yeast nitrogen base components, we found that the isoamyl alcohol production by the Δthi3 strain reduced when thiamine concentrations in the medium were low. Under low-thiamine conditions, both thiamine and thiamine diphosphate (TPP) levels decreased in Δthi3 cells. We also found that the decarboxylase activity of cell-free extracts of the Δthi3 strain cultured in a low-thiamine medium was lower than that of the wild-type strain, but was restored to the level of the wild-type strain when TPP was added. These results indicate that the loss of THI3 lowers the supply of TPP, a cofactor for decarboxylases, resulting in decreased isoamyl alcohol production.

DOI： 10.1016/j.jbiosc.2023.11.006

Nishitani A, Hiramatsu K, Kadooka C, Mori K, Okutsu K, Yoshizaki Y, Takamine K, Tashiro K, Goto M, Tamaki H, Futagami T . Expression of heterochromatin protein 1 affects citric acid production in Aspergillus luchuensis mut. kawachii. . Journal of bioscience and bioengineering 2023年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Bioscience and Bioengineering

A putative methyltransferase, LaeA, controls citric acid production through epigenetic regulation of the citrate exporter gene, cexA, in the white koji fungus Aspergillus luchuensis mut. kawachii. In this study, we investigated the role of another epigenetic regulator, heterochromatin protein 1, HepA, in citric acid production. The ΔhepA strain exhibited reduced citric acid production in liquid culture, although to a lesser extent compared to the ΔlaeA strain. In addition, the ΔlaeA ΔhepA strain showed citric acid production similar to the ΔlaeA strain, indicating that HepA plays a role in citric acid production, albeit with a less-significant regulatory effect than LaeA. RNA-seq analysis revealed that the transcriptomic profiles of the ΔhepA and ΔlaeA strains were similar, and the expression level of cexA was reduced in both strains. These findings suggest that the genes regulated by HepA are similar to those regulated by LaeA in A. luchuensis mut. kawachii. However, the reductions in citric acid production and cexA expression observed in the disruptants were mitigated in rice koji, a solid-state culture. Thus, the mechanism by which citric acid production is regulated differs between liquid and solid cultivation. Further investigation is thus needed to understand the regulatory mechanism in koji.

DOI： 10.1016/j.jbiosc.2023.09.004

Okutsu K, Yamamoto Y, Matsuo F, Yoshizaki Y, Futagami T, Tamaki H, Maeda G, Tsuchida E, Takamine K . Characterization of aroma profiles of kokuto-shochu prepared from three different cultivars of sugarcane. . Journal of bioscience and bioengineering135 ( 6 ) 458 - 465 2023年6月

記述言語：英語出版者・発行元：Journal of Bioscience and Bioengineering

Kokuto-shochu is a traditional Japanese spirit prepared from kokuto, obtained by evaporating water from sugarcane (Saccharum officinarum L.) juice. To clarify the effects of sugarcane cultivars on the sensory quality of kokuto-shochu, we investigated the flavor characteristics and composition of volatiles in kokuto-shochu prepared from kokuto using three different sugarcane cultivars, NiF8, Ni15, and RK97-14. Furthermore, experiments were conducted by using the cultivars collected between 2018 and 2020 to observe annual variations in their properties. The amino acid content of the three kokuto varieties did not differ significantly, but the amino acid content of NiF8 was two to five times higher than that of RK97-14, which was the same for all samples collected in the selected years. The browning degrees of kokuto were also higher in NiF8, and they were positively correlated to the amino acid contents of kokuto. The kokuto-like aroma of shochu made from Ni15 was stronger than that of shochu made from RK97-14. The concentration of ethyl lactate in shochu made from Ni15 was higher, however, the concentration of guaiacol was the lowest in the three cultivars’ products. Shochu made from NiF8 had the highest levels of Maillard reaction products (MRPs; pyrazines and furans), β-damascenone, and guaiacol amounts. In contrast, shochu made from RK97-14 tended to have a fruity flavor, and lower MRP levels than those made from NiF8. Thus, it was shown that sugarcane cultivars affect the sensory characteristics and volatiles in kokuto-shochu.

DOI： 10.1016/j.jbiosc.2023.03.010

Sobol MS, Hoshino T, Delgado V, Futagami T, Kadooka C, Inagaki F, Kiel Reese B . Genome characterization of two novel deep-sea sediment fungi, Penicillium pacificagyrus sp. nov. and Penicillium pacificasedimenti sp. nov., from South Pacific Gyre subseafloor sediments, highlights survivability. . BMC genomics24 ( 1 ) 249 - 249 2023年5月国際誌

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：BMC Genomics

Background: Marine deep subsurface sediments were once thought to be devoid of eukaryotic life, but advances in molecular technology have unlocked the presence and activity of well-known closely related terrestrial and marine fungi. Commonly detected fungi in deep marine sediment environments includes Penicillium, Aspergillus, Cladosporium, Fusarium, and Schizophyllum, which could have important implications in carbon and nitrogen cycling in this isolated environment. In order to determine the diversity and unknown metabolic capabilities of fungi in deep-sea sediments, their genomes need to be fully analyzed. In this study, two Penicillium species were isolated from South Pacific Gyre sediment enrichments during Integrated Ocean Drilling Program Expedition 329. The inner gyre has very limited productivity, organic carbon, and nutrients. Results: Here, we present high-quality genomes of two proposed novel Penicillium species using Illumina HiSeq and PacBio sequencing technologies. Single-copy homologues within the genomes were compared to other closely related genomes using OrthoMCL and maximum-likelihood estimation, which showed that these genomes were novel species within the genus Penicillium. We propose to name isolate SPG-F1 as Penicillium pacificasedimenti sp. nov. and SPG-F15 as Penicillium pacificagyrus sp. nov. The resulting genome sizes were 32.6 Mbp and 36.4 Mbp, respectively, and both genomes were greater than 98% complete as determined by the presence of complete single-copy orthologs. The transposable elements for each genome were 4.87% for P. pacificasedimenti and 10.68% for P. pacificagyrus. A total of 12,271 genes were predicted in the P. pacificasedimenti genome and 12,568 genes in P. pacificagyrus. Both isolates contained genes known to be involved in the degradation of recalcitrant carbon, amino acids, and lignin-derived carbon. Conclusions: Our results provide the first constructed genomes of novel Penicillium isolates from deep marine sediments, which will be useful for future studies of marine subsurface fungal diversity and function. Furthermore, these genomes shed light on the potential impact fungi in marine sediments and the subseafloor could have on global carbon and nitrogen biogeochemical cycles and how they may be persisting in the most energy-limited sedimentary biosphere.

DOI： 10.1186/s12864-023-09320-6

Hiramatsu K, Nishitani A, Okutsu K, Yoshizaki Y, Takamine K, Tamaki H, Futagami T . Efficient gene targeting in Aspergillus chevalieri used to produce katsuobushi. . Bioscience, biotechnology, and biochemistry87 ( 6 ) 672 - 682 2023年3月国際誌

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Bioscience, Biotechnology and Biochemistry

In this study, we developed an efficient gene targeting system for the osmophilic fungus Aspergillus chevalieri, which is commonly used in the production of a dried bonito, katsuobushi. Specifically, we utilized the clustered regularly interspaced short palindromic repeats/Cas9 system to disrupt the ATP sulfurylase encoding sC gene. This results in methionine auxotroph and selenate-resistance. Additionally, we disrupted the DNA ligase IV encoding ligD gene, which is required for nonhomologous end joining. Using the sC marker and selenate-resistance as a selection pressure, we were able to rescue the sC marker and generate a ligD sC strain. We determined that the gene targeting efficiency of the ligD sC strain was significantly higher than that of the parental sC strain, which indicates that this strain provides efficient genetic recombination for the genetic analysis of A. chevalieri.

DOI： 10.1093/bbb/zbad033

Tiantian Wang, Isao Hanashiro, Yumiko Yoshizaki, Yuki Kobashi, Suzuka Noda, Kayu Okutsu, Taiki Futagami, Hisanori Tamaki, Kazunori Takamine . Shochu Koji Microstructure and Starch Structure during Preparation. . Journal of applied glycoscience70 ( 4 ) 109 - 117 2023年

記述言語：英語掲載種別：研究論文（学術雑誌）

In this study, we investigated the changes in composition, microstructure, and starch molecular structure of shochu koji during preparation. We observed that the gelatinized and outer part of starch was decomposed in priority during the early and middle preparation stages. The gap between the starch granules increased with the delayed time. Finally, the koji microstructure became spongy. Shochu koji mold produced two α-amylases in different expression manners. Acid-labile α-amylase was produced in the early and middle preparation stages. Acid-stable α-amylase and saccharification power were produced in the middle and late stages. Throughout the koji preparation, reducing sugars content reached approximately 13-20 % of the total sugar content, with glucose representing over 70 % of the reducing sugars. α-Glucan fragments with C chains of degree of polymerization (DP) 4-73 were observed in the early and middle stages (<23 h), indicating the degradation of amylopectin at long B chains. In the latter stage, the amount of C chains of DP 6-30 decreased, while the longer C chains (DP 30<) did not change. These results showed that acid-labile α-amylase, acid-stable α-amylase, and saccharification enzymes including glucoamylase and α-glucosidase work preferentially on the amorphous regions of starch granules, and cooperative action of these enzymes during koji preparation contributes to the formation of the observed microstructure. Our study is the first report on the decomposition schemes of starch and the microstructure forming process in shochu koji.

DOI： 10.5458/jag.jag.JAG-2023_0006

Li B, Yoshizaki Y, Okutsu K, Haruyama Y, Sato Y, Futagami T, Tamaki H, Takamine K . Factors that cause replacement of shochu yeast by wild yeast upon Sashi-moto repetition. . Journal of bioscience and bioengineering134 ( 4 ) 326 - 330 2022年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Bioscience and Bioengineering

In shochu-making, a small amount of fermenting moromi is added to a koji/water mixture instead of yeast culture to initiate fermentation. This is a characteristic process called Sashi-moto. It is known that shochu yeast is replaced by wild yeast upon repetition of Sashi-moto. The shochu yeast strains Kagoshima No. 2 (K2), Kagoshima No. 4 (C4), and Kagoshima No. 5 (H5), but not Kagoshima No. 6 (A6), were replaced by wild yeast (strain No. S5-g). K2 and C4 were easily replaced compared to H5, and the specific growth rates of K2 and C4 were lower than that of S5-g under higher osmotic pressure. Although the specific growth rate of H5 was higher than that of S5-g, its yeast population at the stationary phase was smaller than S5-g. On the other hand, both the specific growth rate and yeast population of A6 were higher than those of S5-g. The specific growth rate of yeast would be affected by osmotic tolerance and specific characters of the yeast strain.

DOI： 10.1016/j.jbiosc.2022.07.011

曾伝濤, 劉夢迪, 吉﨑由美子, 奥津果優, 二神泰基, 玉置尚徳, 髙峯和則 . サトイモ焼酎の香味特性と焼酎粕の機能性 . 日本醸造協会誌117 ( 10 ) 701 - 711 2022年10月

劉根僑, 吉﨑由美子, 奥津果優, 二神泰基, 玉置尚徳, 髙峯和則 . サツマイモ固体糖化後仕込みによる芋焼酎製造の可能性 . 日本醸造協会誌117 ( 10 ) 712 - 723 2022年10月

Futagami T . The white koji fungus Aspergillus luchuensis mut. kawachii. . Bioscience, biotechnology, and biochemistry86 ( 5 ) 574 - 584 2022年4月査読国際誌

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Bioscience, Biotechnology and Biochemistry

The white koji fungus, Aspergillus luchuensis mut. kawachii, is used in the production of shochu, a traditional Japanese distilled spirit. White koji fungus plays an important role in the shochu production process by supplying amylolytic enzymes such as α-amylase and glucoamylase. These enzymes convert starch contained in primary ingredients such as rice, barley, buckwheat, and sweet potato into glucose, which is subsequently utilized by the yeast Saccharomyces cerevisiae to produce ethanol. White koji fungus also secretes large amounts of citric acid, which lowers the pH of the shochu mash, thereby preventing the growth of undesired microbes and enabling stable production of shochu in relatively warm regions of Japan. This review describes the historical background, research tools, and recent advances in studies of the mechanism of citric acid production by white koji fungus.

DOI： 10.1093/bbb/zbac033

Mori K, Kadooka C, Oda K, Okutsu K, Yoshizaki Y, Takamine K, Tashiro K, Goto M, Tamaki H, Futagami T . Chromosome-level genome sequence data and analysis of the white koji fungus, Aspergillus luchuensis mut. kawachii IFO 4308. . Data in brief41 107888 - 107888 2022年4月国際誌

Ketkaeo S, Nagano Y, Baba S, Kimura K, Futagami T, Sanpamongkolchai W, Kobayashi G, Goto M . Development of Monascus purpureus monacolin K-hyperproducing mutant strains by synchrotron light irradiation and their comparative genome analysis. . Journal of bioscience and bioengineering133 ( 4 ) 362 - 368 2022年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Bioscience and Bioengineering

Monascus purpureus have been used for making koji and other fermented foods and supplements. M. purpureus characteristically produces monacolin K (MK), a secondary metabolite that competitively inhibits cholesterol synthesis. Synchrotron light irradiation was applied to induce mutation in the strain KUPM5 to improve the MK-producing ability of M. purpureus strain KUPM5. Screening by a bioassay utilizing sensitivities to yeast Saccharomyces cerevisiae from 936 colonies allows isolating three mutant strains: SC01, SC02, and SC03. These mutant strains and the parental strain KUPM5 were subjected to make koji using rice, and their metabolites were compared. All strains SC01, SC02, and SC03 in koji showed higher production of MK than the strain KUPM5. Particularly, the SC02 strain produced MK threefold higher than KUPM5 and maintained the production capabilities of other metabolites, including red, yellow, and orange pigments, mycelial contents, and α-amylase activity comparable to those of the strain KUPM5. Comparative genome analysis among strain KUPM5 and the mutants revealed that synchrotron light irradiation introduced mutations in approximately 90% of the total genes, including SNV, MNV, and indel mutations. The frequencies of SNV substitution in the whole genome occupied 68.96% of all mutations, of which 92.38% were transversions and 7.62% were transitions. This study, therefore, proved the synchrotron light irradiation was highly efficient for the strain improvement of a filamentous fungus, M. purpureus, and provided insights into the properties of mutation in the fungus by this mutagen.

DOI： 10.1016/j.jbiosc.2021.11.011

Oussou-Azo FA, Futagami T, Vestergaard MCM . Immuno-Dipstick for Colletotrichum gloeosporioides Detection: Towards On-Farm Application. . Biosensors12 ( 2 ) 49 - 49 2022年1月国際誌

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Biosensors

Early and quick detection of pathogens are crucial for managing the spread of infections in the biomedical, biosafety, food, and agricultural fields. While molecular diagnostics can offer the specificity and reliability in acute infectious diseases, detection of pathogens is often slowed down by the current benchtop molecular diagnoses, which are time consuming, labor intensive, and lack the mobility for application at the point-of-need. In this work, we developed a complete on-farm use detection protocol for the plant-devastating anthracnose agent: Colletotrichum gloeosporioides. Our methods combined a simplified DNA extraction on paper that is compatible with loop-mediated isothermal amplification (LAMP), coupled with paper-based immunoassay lateral flow sensing. Our results offer simple, quick, easy, and a minimally instrumented toolkit for Colletotrichum gloeosporioides detection. This scalable and adaptable platform is a valuable alternative to traditional sensing systems towards on-the-go pathogen detection in food and agriculture, biomedical, and other fields.

DOI： 10.3390/bios12020049

Futagami T, Goto M . Insights regarding sirtuin-dependent gene regulation during white koji production. . Communicative & integrative biology15 ( 1 ) 92 - 95 2022年査読国際誌

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Communicative and Integrative Biology

White koji, a solid-state culture of Aspergillus luchuensis mut. kawachii using grains such as rice and barley, is used as a source of amylolytic enzymes and citric acid for the production of shochu, a traditional Japanese distilled spirit. We previously characterized changes in gene expression that affect the properties of white koji during the shochu production process; however, the underlying regulatory mechanisms were not determined. We then characterized the NAD+-dependent histone deacetylase sirtuin, an epigenetic regulator of various biological phenomena, in A. l. mut. kawachii and found that sirtuin SirD is involved in expression of α-amylase activity and citric acid accumulation. In this addendum study, we measured the NAD+/NADH redox state and found that the NAD+ level and NAD+/NADH ratio decrease during koji production, indicating that sirtuin activity declines in the late stages of koji culture. By comparing these results with transcriptomic data obtained in our previous studies, we estimate that approximately 35% of the gene expression changes during white koji production are SirD dependent. This study provides clues to the mechanism of gene expression regulation in A. l. mut. kawachii during the production of white koji.

DOI： 10.1080/19420889.2022.2051844

Zhao Z., Sugimachi M., Yoshizaki Y., Yin X., Han X.L., Okutsu K., Futagami T., Tamaki H., Takamine K. . Correlation between key aroma and manufacturing processes of rice-flavor baijiu and awamori, Chinese and Japanese traditional liquors . Food Bioscience44 2021年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Food Bioscience

In this study, we compared the flavor profiles Chinese rice-flavor baijiu and Japanese awamori—traditional liquors with similar manufacturing processes. Citric acid and lactic acid were the major acid constituents in the mash of awamori and rice-flavor baijiu, respectively. The amino acid content of awamori mash was greater than that of rice-flavor baijiu owing to the higher proteolytic activities in the former. The high amino acid content also induced yeast growth at the early stage of fermentation in awamori mash, thus increasing the fermentation rate. Sensory evaluation revealed that rice-flavor baijiu had a significantly stronger alcoholic, floral, and fruity aroma, whereas the awamori had a strong sour, koji-like, oily, and cereal-like aromas. We determined the aroma threshold of (+)-ethyl D-lactate (15,400 μg/L) and (−)-ethyl L-lactate (12,500 μg/L). Both compounds have a common sweet, fruity, and green leaves-like aroma and a different nuance; (+)-ethyl D-lactate has a peach- and citrus-like aromas, and (−)-ethyl L-lactate has an apple-like and milky aromas. In rice-flavor baijiu, (−)-ethyl L-lactate constitutes the major isoform, as evident from the higher concentration of L (+)-lactic acid in the mash. Higher alcohols, (−)-ethyl L-lactate, and isoamyl acetate contents were greater in rice-flavor baijiu, while 1-octen-3-ol and acetic acid were greater in awamori. These results showed that solid-state saccharification contributed to the production of ethyl lactate by supplying in the mash a large amount of lactic acid produced by Rhizopus oryzae and koji contributed to the production of 1-octen-3-ol via the high fatty acid oxygenase activity produced by Aspergillus luchuensis.

DOI： 10.1016/j.fbio.2021.101375

Zitai Wang, Kayu Okutsu, Yumiko Yoshizaki, Taiki Futagami, Hisanori Tamaki, Takuro Maruyama, Kazufumi Toume, Katsuko Komatsu, Fumio Hashimoto, Kazunori Takamine . Effects of microbial fermentation on enzyme activity and volatile properties of Massa Medicata Fermentata . Traditional & Kampo Medicine9 ( 1 ) 10 - 17 2021年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Wiley

Aim: Massa Medicata Fementata (MMF) is a crude drug used in East Asia to treat anorexia and dyspepsia. It is prepared from wheat and several herbs through microbial fermentation using Aspergillus sp. and Rhizopus sp. There is great difference in the quality of commercial MMF, and the microbes of MMF are suggested to affect its quality. We investigated the effects of microbial fermentation on the quality of MMF. Methods: Raw materials of MMF were mixed according to the ratio listed in the National Standard for Chinese Patent Drugs, and MMF was prepared using pure cultures of Aspergillus oryzae or Rhizopus oryzae. Digestive enzyme activities (α-amylase, protease, and lipase) and volatile compounds were measured using an analytical kit and GC–MS, respectively. Results: Enzyme activity increased in MMF. MMF prepared with A. oryzae (MMF-A) showed higher α-amylase and lipase activities than that prepared with R. oryzae (MMF-R). Protease activity was marginally higher in MMF-R than in MMF-A. GC–MS analysis revealed that terpenoids decreased with fermentation; however, 2,3-butanediol, acetoin, and guaiacol were detected in MMF only. C8 compounds such as 1-octen-3-ol were higher in MMF-A than MMF-R; however, aromatic compounds such as 4-vinylguaiacol and pyrazines were higher in MMF-R than MMF-A. Conclusion: Microbial fermentation contributes to increased enzyme activity and changes in MMF volatiles. These properties of MMF were considerably affected by the microbes used, and it is proposed in this study that it is important to have microbial control in the production of commercial MMF.

DOI： 10.1002/tkm2.1303

その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/tkm2.1303

Hirose J, Watanabe T, Futagami T, Fujihara H, Kimura N, Suenaga H, Goto M, Suyama A, Furukawa K . A New ICEclc Subfamily Integrative and Conjugative Element Responsible for Horizontal Transfer of Biphenyl and Salicylic Acid Catabolic Pathway in the PCB-Degrading Strain Pseudomonas stutzeri KF716. . Microorganisms9 ( 12 ) 2021年11月国際誌

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Microorganisms

Integrative and conjugative elements (ICEs) are chromosomally integrated self-transmissible mobile genetic elements. Although some ICEs are known to carry genes for the degradation o-f aromatic compounds, information on their genetic features is limited. We identified a new member of the ICEclc family carrying biphenyl catabolic bph genes and salicylic acid catabolic sal genes from the PCB-degrading strain Pseudomonas stutzeri KF716. The 117-kb ICEbph-sal KF716 contains common core regions exhibiting homology with those of degradative ICEclc from P. knackmussii B13 and ICEXTD from Azoarcus sp. CIB. A comparison of the gene loci collected from the public database revealed that several putative ICEs from P. putida B6-2, P, alcaliphila JAB1, P. stutzeri AN10, and P. stutzeri 2A20 had highly conserved core regions with those of ICEbph-sal KF716, along with the variable region that encodes the catabolic genes for biphenyl, naphthalene, toluene, or phenol. These data indicate that this type of ICE subfamily is ubiquitously distributed within aromatic compound-degrading bacteria. ICEbph-sal KF716 was transferred from P. stutzeri KF716 to P. aeruginosa PAO1 via a circular extrachromosomal intermediate form. In this study, we describe the structure and genetic features of ICEbph-sal KF716 compared to other catabolic ICEs.

DOI： 10.3390/microorganisms9122462

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