Isolation and identification of the antimicrobial substance included in tempeh using Rhizopus stolonifer NBRC 30816 for fermentation

Masahiro Ito, Takashi Ito, Hideyuki Aoki, Koshi Nishioka, Tsugumi Shiokawa, Hiroko Tada, Yuki Takeuchi, Nobuyuki Takeyasu, Tadashi Yamamoto, Shogo Takashiba

Research output: Contribution to journalArticle


In this study, we focus on the antimicrobial properties of tempeh, a soybean fermented food, against oral bacteria. Tempeh showed antimicrobial activity against dental caries pathogenic bacterium Streptococcus mutans at a final concentration of 1 mg/mL. An antimicrobial substance contained in tempeh was present in the 100 kDa or greater fraction generated by ultrafiltration, but it was found not to be proteinaceous by native-PAGE, SDS-PAGE and protein degradation tests. Next, when the fraction was purified with an ODS column, the 80% and 100% methanol eluates showed antimicrobial activity against S. mutans. The 100% methanol eluate was further subjected to a 2nd column purification, and isolation of the target was confirmed by HPLC. When the isolated material was analyzed by ESI-MS, the m/z was 279.234. Further analysis by Raman spectroscopy revealed a peak similar to linoleic acid. This substance also possessed antimicrobial properties equivalent to linoleic acid.

Original languageEnglish
Article number108645
JournalInternational Journal of Food Microbiology
Publication statusPublished - Jul 16 2020



  • Antibacterial
  • Fermented soybean food
  • Linoleic acid
  • Oral infection

ASJC Scopus subject areas

  • Food Science
  • Microbiology

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