Tracing microbiota changes in yamahai-moto, the traditional Japanese sake starter.

Sake is made from steamed rice, malted rice, and water. Sake production begins with the preparation of a small-scale starter (moto); the quality of moto significantly influences the flavor and richness of sake. In the traditional starter, yamahai-moto, the growth of naturally occurring lactic acid bacteria represses the putrefactive micro-organisms, whereas in the modern starter, sokujo-moto, this is achieved by adding lactic acid. In this study, the successive change in bacterial flora of yamahai-moto was analyzed by pyrosequencing 16S ribosomal RNA genes. Lactobacillus was dominant throughout the process (93-98%). Nitrate-reducing bacteria that have been generally assumed to be the first colonizers of yamahai-moto were scarcely found in the early stage, but Lactobacillus acidipiscis dominated. Lactobacillus sakei drastically increased in the middle stage. This is the first report, though one case study, to show how the early stage microbiota in Japanese yamahai-moto is varyingly controlled without nitrate-reducing bacteria using next-generation sequencing.

The γ-aminobutyric acid-producing ability under low pH conditions of lactic acid bacteria isolated from traditional fermented foods of Ishikawa Prefecture, Japan, with a strong ability to produce ACE-inhibitory peptides.

Many traditional fermented products are onsumed in Ishikawa Prefecture, Japan, such as kaburazushi, narezushi, konkazuke, and ishiru. Various kinds of lactic acid bacteria (LAB) are associated with their fermentation, however, characterization of LAB has not yet been elucidated in detail. In this study, we evaluated 53 isolates of LAB from various traditional fermented foods by taxonomic classification at the species level by analyzing the 16S ribosomal RNA gene (rDNA) sequences and carbohydrate assimilation abilities. We screened isolates that exhibited high angiotensin-converting enzyme (ACE) inhibitory activities in skim milk or soy protein media and produced high γ-aminobutyric acid (GABA) concentrations in culture supernatants when grown in de Man Rogosa Sharpe broth in the presence of 1% (w/v) glutamic acid. The results revealed that 10 isolates, i.e., Lactobacillus buchneri (2 isolates), Lactobacillus brevis (6 isolates), and Weissella hellenica (2 isolates) had a high GABA-producing ability of >500 mg/100 ml after 72 h of incubation at 35 °C. The ACE inhibitory activity of the whey cultured with milk protein by using L. brevis (3 isolates), L. buchneri (2 isolates), and W. hellenica (2 isolates) was stronger than that of all whey cultured with soy protein media, and these IC50 were < 1 mg protein/ml. Three of 10 isolates had high GABA-producing activities at pH 3, suggesting that they could be powerful candidates for use in the fermentation of food materials having low pH.

Pyrosequencing analysis of microbiota in Kaburazushi, a traditional medieval sushi in Japan.

The processing of archetypal Japanese sushi involves microbial fermentation. The traditional sushi kaburazushi, introduced in the middle ages, is made by fermenting salted yellow tail, salted turnip, and malted rice, and is distinguished from the ancient sushi narezushi, made from fish and boiled rice. In this study, we examined changes in the microbial population during kaburazushi fermentation by pyrosequencing the 16S ribosomal RNA genes (rDNA) of the organisms in the fermentation medium. Ribosomal Database Project Classifier analysis identified 31 genera, among which Lactobacillus drastically increased during fermentation (150-fold increment over 8 d), while the relative populations of the other gram-positive bacteria (Staphylococcus and Bacillus) decreased. Basic Local Alignment Search Tool analysis revealed the dominant species to be L. sakei. This organism constituted approximately 90% of Lactobacillus and 79% of total microbiota. The taxonomic diversity and species richness (assayed by Shannon-Weiner Index and Chao 1, respectively) were not significantly different between middle-ages kaburazushi and ancient narezushi. Both types were characterized by the preferential growth of Lactobacillales.

Inhibitive effects of alkyl gallates on hyaluronidase and collagenase.

A series of the gallate esters of n-alkanols (C(1)-C(12)) was examined to determine their inhibitory activities against hyaluronidase and collagenase. Hexyl, heptyl, octyl, nonyl, and decyl gallates inhibited both hyaluronidase and collagenase, and the most potent inhibitor was octyl gallate against both enzymes. Octyl 3,5-dihydroxybenzoate showed inhibitory effects on hyaluronidase, whereas collagenase was inhibited by octyl 3,4-dihydroxybenzoate.

Purification and characterization of a corrinoid-compound in an edible cyanobacterium Aphanizomenon flos-aquae as a nutritional supplementary food.

The vitamin B12 concentration of the dried cells of Aphanizomenon flos-aquae was determined by both microbiological method with Lactobacillus delbrueckeii ATCC7830 and chemiluminescence method with intrinsic factor. The Aphanizomenon cells contained 616.3 +/- 30.3 micro g (n = 4) of vitamin B12 per 100 g of the dried cells by the microbiological method. The values determined with the chemiluminescence method, however, were only about 5.3% of the values determined by the microbiological method. A corrinoid-compound was purified from the dried cells and characterized. The purified corrinoid-compound was identified as pseudovitamin B12 (an inactive corrinoid-compound for humans) by silica gel 60 TLC, C18 reversed-phase HPLC, ultraviolet-visible spectroscopy, and 1H NMR spectroscopy. The results suggest that the Aphanizomenon cells are not suitable for use as a vitamin B12 source, especially in vegans.