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Applied Microbiology and Biotechnology

, Volume 55, Issue 6, pp 771–776 | Cite as

Absence of aflatoxin biosynthesis in koji mold (Aspergillus sojae)

  • Kenichiro Matsushima
  • Kumiko Yashiro
  • Yoshiki Hanya
  • Keietsu Abe
  • Kimiko Yabe
  • Takashi Hamasaki
Original Paper

Abstract.

Ten strains isolated from industrial soy sauce producing koji mold were identified as Aspergillus sojae and distinguished from Aspergillus parasiticus morphologically and physiologically. There was no detectable aflatoxin in any culture extracts of A. sojae strains. Strain 477 was chosen as a representative strain of industrial A. sojae for further molecular analysis. All enzymatic activities associated with the aflatoxin biosynthesis were not detected or negligible in strain 477 compared with that of the A. parasiticus strain. Southern analysis suggested that the genomic DNA of strain 477 contained aflatoxin biosynthetic pathway genes. In contrast, all industrial strains lacked detectable transcripts of aflR, the main regulatory gene for aflatoxin biosynthesis, under the aflatoxin-inducing condition. Our data suggest that defects in aflR expression cause the lack of expression of aflatoxin-related genes which results in the absence of aflatoxin biosynthesis in A. sojae strains.

Keywords

Mold Aspergillus Aflatoxin Biosynthetic Pathway Pathway Gene 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 2001

Authors and Affiliations

  • Kenichiro Matsushima
    • 1
  • Kumiko Yashiro
    • 1
  • Yoshiki Hanya
    • 1
  • Keietsu Abe
    • 1
  • Kimiko Yabe
    • 2
  • Takashi Hamasaki
    • 3
  1. 1.Kikkoman Corporation, 399 Noda, Noda-City, 278-0037 Japan
  2. 2.National Food Research Institute, 2-1-2 Kannondai, Tsukuba, 305-8642 Japan
  3. 3.Faculty of Agriculture, 101-4 Minami, Koyama-cho, Tottori, Tottori University, 680-8553, Japan

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