title: Japanese traditional dietary fungus koji Aspergillus oryzae functions as a prebiotic for Blautia coccoides through glycosylceramide: Japanese dietary fungus koji is a new prebiotic.
abstract: BACKGROUND
  The Japanese traditional cuisine, Washoku, considered to be responsible for increased longevity among the Japanese, comprises various foods fermented with the non-pathogenic fungus Aspergillus oryzae (koji). We have recently revealed that koji contains an abundant amount of glycosylceramide. Intestinal microbes have significant effect on health. However, the effects of koji glycosylceramide on intestinal microbes have not been studied.
  
  
  METHODS
  Glycosylceramide was extracted and purified from koji. C57BL/6N mice were fed a diet containing 1 % purified koji glycosylceramide for 1 week. Nutritional parameters and faecal lipid constituents were analyzed. The intestinal microbial flora of mice on this diet was investigated.
  
  
  RESULTS
  Ingested koji glycosylceramide was neither digested by intestinal enzymes nor was it detected in the faeces, suggesting that koji glycosylceramide was digested by the intestinal microbial flora. Intestinal microbial flora that digested koji glycosylceramide had an increased ratio of Blautia coccoides. Stimulation of B. coccoides growth by pure koji glycosylceramide was confirmed in vitro.
  
  
  CONCLUSIONS
  Koji functions as a prebiotic for B. coccoides through glycosylceramide. Since there are many reports of the effects of B. coccoides on health, an increase in intestinal B. coccoides by koji glycosylceramide might be the connection between Japanese cuisine, intestinal microbial flora, and longevity.
authors: Department of Environmental Science, Faculty of Agriculture, Saga University, Honjo-cho, Saga City, Saga Japan.
authors: Hiroshi
authors: H
authors: Hamajima
authors: Department of Environmental Science, Faculty of Agriculture, Saga University, Honjo-cho, Saga City, Saga Japan.
authors: Haruka
authors: H
authors: Matsunaga
authors: Department of Environmental Science, Faculty of Agriculture, Saga University, Honjo-cho, Saga City, Saga Japan.
authors: Ayami
authors: A
authors: Fujikawa
authors: Department of Environmental Science, Faculty of Agriculture, Saga University, Honjo-cho, Saga City, Saga Japan.
authors: Tomoya
authors: T
authors: Sato
authors: Department of Applied Biochemistry and Food Science, Faculty of Agriculture, Saga University, Honjo-cho, Saga City, Saga Japan.
authors: Susumu
authors: S
authors: Mitsutake
authors: Faculty of Health and Nutrition Science, Nishikyushu University, Ozaki, Kanzaki-cho, Kanzaki City, Saga Japan.
authors: Teruyoshi
authors: T
authors: Yanagita
authors: Department of Applied Biochemistry and Food Science, Faculty of Agriculture, Saga University, Honjo-cho, Saga City, Saga Japan.
authors: Koji
authors: K
authors: Nagao
authors: Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan.
authors: Jiro
authors: J
authors: Nakayama
authors: Department of Environmental Science, Faculty of Agriculture, Saga University, Honjo-cho, Saga City, Saga Japan.
authors: Hiroshi
authors: H
authors: Kitagaki
keywords: Aspergillus; Blautia; Glycosylceramide; Intestinal microbial flora; Japanese cuisine; Koji; Prebiotic