Leuconostoc encompasses a number of species that frequently appear in foods where they play different roles, ranging from ripening to spoiling. The number of available Leuconostoc genomes has recently increased and enabled the precise taxonomic and phylogenetic delineation of species. Nonetheless, a thorough investigation of the functions and the metabolic potential of Leuconostoc species has never been accomplished. In this study, all the currently available 553 Leuconostoc genomes were downloaded from NCBI GenBank and annotated utilizing specific tools in order to reconstruct the metabolic potential of the genus in terms of carbohydrate hydrolysis and fermentative pathways, transporters, and anabolic potential. The analysis revealed that species cluster based on their metabolic potential, showing unique adaptation and ecological roles. Pentose phosphate and phosphoketolase pathways were highlighted as the main ones of central metabolism. The various identified PTS and ABC transporters showed adaptability to different sugars. The metabolic diversity described in this study not only supports the role of Leuconostoc spp. in natural ecosystems but also highlights their potential in industrial applications, particularly in the fermentation industry where their ability to metabolize a wide range of substrates can be harnessed for the production of various fermented foods and bioproducts.

Introduction: Clostridia is a major microbial class in the human gut, crucial for fermenting undigested carbohydrates and proteins, which produce short-chain fatty acids essential for gut health and immune balance. This study revised the taxonomic classification and phylogeny of all the species of intestinal Clostridia catalogued in the Unified Human Gastrointestinal Genome database using a whole-genome approach and assessed butyrate and propionate producing species. Methods: A total of 1,897 Clostridia species, including those with recognised binomial nomenclature and those lacking formal taxonomic classification, were retrieved and reclassified using GTDB-Tk. Their phylogeny was determined by identifying, concatenating, and aligning the 120 ubiquitous single-copy proteins defined in the GTDB. Average amino acid identity (AAI), percentage of conserved proteins (POCP), and phylogenetic relationships were used to organize the species into genera and families. The presence of enzymes belonging to the biosynthetic pathways for butyrate and propionate production was investigated in all genomes with the tool GapSeq. Results: Reclassification of the genomes resulted in 404 recognised species and 1,493 species lacking formal taxonomic classification. Oscillospirales and Lachnospirales encompassed most of the species. The pathways leading to butyrate and propionate production were analyzed in their entirety, revealing 519 species as potential butyrate producers, 257 as potential propionate producers and 77 capable of producing both. To assess the abundance of each species, 151 faecal metagenomes of healthy subjects were profiled, indicating that butyrate producing Clostridia accounted on average for 28.0% of each microbiome. Conclusions: This study offers a comprehensive overview of intestinal Clostridia diversity, emphasising their role in gut ecosystems and their potential for butyrate and propionate production.

Food waste valorization represents a critical challenge and opportunity for sustainable food systems. This study investigated the reuse of sauce production by-products through two approaches: (i) solvent-free recovery of an oil-rich fraction and (ii) development of polymeric films for potential edible or biodegradable packaging. Centrifugation recovered approximately 10 g per 100 g of by-product. The recovered oil was characterized for total polyphenols and fatty acid composition, showing a profile consistent with vegetable oils (mainly olive oil), with minor contributions attributable to cheese and meat components. A full factorial design was used to prepare and test films and to study the effects of the three ingredients used, namely pectin, carvacrol, and sauce by-products, on their mechanical, surface, and antibacterial properties. Chemometric analysis based on principal component analysis (PCA) and regression-based modeling (multiple linear regression and response surface analysis) was applied to identify the relationships among the responses and the most influential factors. Among the tested formulations, N3 (low pectin and by-product; high carvacrol) showed the most favorable overall balance, combining the strongest antibacterial activity (mean inhibition halo diameter of 14.8 mm and 17.8 mm against Escherichia coli ATCC 11229 and Staphylococcus aureus ATCC 6538, respectively) with favorable mechanical performance, including the highest maximum force (0.53 ± 0.01 MPa) and elastic modulus, (6.8 ± 0.01 MPa) and intermediate elongation (12 ± 3%) and work at maximum force (11.9 ± 0.9 N mm).

C-di-AMP is a bacterial second messenger recognized by host immune sensors such as the STING pathway, linking gut microbiota activity to tumor immunity. This interaction holds significant therapeutic potential particularly for oncologic patients, given the increasingly recognized relationship between gut microbiota and tumor immunity. Recent evidence shows that microbial c-di-AMP can enhance anti-tumor responses and improve the efficacy of PD-1/PD-L1 blockade and radiotherapy. This study identified gut microbial species capable of synthesizing c-di-AMP by mining the Unified Human Gastrointestinal Protein catalogue for diadenylate cyclases (DACs), generating a database of 4,228 DACs across 3,901 species out of 4,744 presents in the Unified Human Gastrointestinal Genome catalogue. Analysis of metagenomic data from 190 healthy subjects and 569 cancer patients (melanoma, NSCLC, renal carcinoma) revealed a significantly higher abundance of DAC-encoding species in healthy microbiota, with no differences between responders and non-responders to immunotherapy. These findings indicate that c-di-AMP-producing bacteria are depleted in cancer-associated microbiota, supporting further studies on their role in modulating anti-tumor immunity.