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

• Published in: International journal of food microbiology Vol. 325; p. 108645
• Main Authors: Ito, Masahiro, Ito, Takashi, Aoki, Hideyuki, Nishioka, Koshi, Shiokawa, Tsugumi, Tada, Hiroko, Takeuchi, Yuki, Takeyasu, Nobuyuki, Yamamoto, Tadashi, Takashiba, Shogo
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 16.07.2020; Elsevier BV
• Subjects: Anti-Infective Agents - analysis; Anti-Infective Agents - isolation & purification; Antibacterial; Antiinfectives and antibacterials; Antimicrobial activity; Antimicrobial agents; Bacteria; Biodegradation; Dental caries; Dental Caries - microbiology; Dental Caries - prevention & control; Dental materials; Fermentation; Fermented food; Fermented Foods - analysis; Fermented soybean food; Gel electrophoresis; Glycine max - metabolism; Glycine max - microbiology; High-performance liquid chromatography; Linoleic acid; Liquid chromatography; Methanol; Oral infection; Plant Extracts - pharmacology; Raman spectroscopy; Rhizopus - metabolism; Sodium lauryl sulfate; Soy Foods - analysis; Soy products; Soybeans; Streptococcus infections; Streptococcus mutans - drug effects; Tempeh; Ultrafiltration; Fermented soybean food; Antibacterial; Oral infection; Linoleic acid
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2020.108645

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. •Tempeh demonstrated antimicrobial activity against Streptococcus mutans.•Antibacterial activity was shown at a concentration of 1 mg/mL after extraction with water.•The antimicrobial substance displayed composition and bonding similar to linoleic acid.•This substance exhibited similar antibacterial properties to linoleic acid.