Biofilm inhibition of cariogenic Streptococcus mutans by Japanese fermented food natto

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K18704
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Food science
• Research Institution: Nihon University
• Principal Investigator: NARISAWA Naoki 日本大学, 生物資源科学部, 講師 (90632034)
• Research Collaborator: TAKENAGA Fumio ; TORII Yasuyoshi ; ABE Shin ; NAKAMURA Tomoyo ; IWAMOTO Rika ; KAWASAKI Yukimasa
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 納豆 / う蝕 / バイオフィルム / Streptococcus mutans / ナットウキナーゼ

Outline of Final Research Achievements

Natto made from soybeans cultured with Bacillus subtilis natto contains an abundance of proteolytic enzymes. In this study, we investigated the correlation between the protease activity of extracts from 36 commercially available natto products and the inhibition of biofilm formation. The biofilm inhibitory effect was found to correlate with the level of protease activity in the natto extracts, without reducing the viable cell numbers. The natto extract markedly inhibited the production of a water-insoluble glucan by Streptococcus mutans, which is the main agent involved in the formation of biofilm by cariogenic streptococci. The characteristics of the protease present in the extract were similar to those of nattokinase. Our results indicate that the protease activity exhibited by extracts of the Japanese fermented food natto reduces the risk of caries by inhibiting biofilm formation.

Free Research Field

応用微生物