New insights into microorganism-derived antibiotics based on identification and antimicrobial activity of antibiotic-producing actinomycetes in kusaya gravy that lead to its high preservability.

Kusaya shows a high preservability due to the microorganism-derived antibiotics contained in kusaya gravy, which is important for kusaya manufacturing. However, the antimicrobial compounds and its producing bacteria, as well as the antimicrobial activity of the kusaya gravy itself, have remained unknown. In this study, we isolated antibiotic-producing bacteria of the genus Streptomyces from kusaya gravy from Hachijojima and found that they produced antibacterial substances against various fungi and bacteria.

Causality Verification for the Correlation between the Presence of Nonstarter Bacteria and Flavor Characteristics in Soft-Type Ripened Cheeses.

Flavor characteristics of ripened cheese are established by various bacteria, such as lactic acid bacteria, , and , which spontaneously develop during the cheese-manufacturing process. We previously revealed the relationship between bacterial microbiota and flavor components in soft-type ripened cheeses by using a multiomics approach that combined metagenomics and metabolomics; however, we could not establish a causal relationship. This study aimed to substantiate the causal nature of the correlations revealed by the multiomics approach by using cheese-ripening tests with single isolate inoculation.

Evaluation of the Relationships Between Microbiota and Metabolites in Soft-Type Ripened Cheese Using an Integrated Omics Approach.

Cheese ripening is effected by various microorganisms and results in the characteristic flavors of cheese. Owing to the complexity of the microbiota involved, the relationship between microorganisms and components during ripening remains unclear. In this study, metagenomics and metabolomics were integrated to reveal these relationships in three kinds of surface mold-ripened cheeses and two kinds of bacterial smear-ripened cheeses.