Research on peptide requirement of lactobacilli resident in human small intestine

2016 Fiscal Year Final Research Report

• Project/Area Number: 26870393
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Eating habits; Applied microbiology
• Research Institution: Okayama University
• Principal Investigator: ARAKAWA Kensuke 岡山大学, 環境生命科学研究科, 准教授 (50609930)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 乳酸菌 / Lactobacillus gasseri / 乳 / 大豆 / ムチン / ペプチド / プロテアーゼ / ペプシン

Outline of Final Research Achievements

Lactobacillus gasseri is well-known as a species of probiotic lactic acid bacteria resident in human small intestine. However, the usability of Lb. gasseri as a fermentation starter was limited, because of its indefinite auxotrophy. In this study, we first revealed that Lb. gasseri requires peptides for growth, and that the peptide requirement would be caused by low activity of cell-envelope proteinases of Lb. gasseri. Next, we developed new two methods for milk fermentation using Lb. gasseri without any supplementation of peptides. In a method, fermentation was achieved after hydrolysis of milk proteins using food-grade proteinases particularly pepsin. In another, cocultivation with selected coccal strains of lactic acid bacteria was used. In addition, it was found that Lb. gasseri can assimilate endogenous peptides such as pepsinolytic hydrolysates of gastric mucin, as well as exogenous peptides generated from orally ingested food proteins.

Free Research Field

酪農科学, 畜産物利用学, 食品加工学, 食品微生物学, 乳酸菌学, 発酵学