The functional landscape of the skin microbiome is largely defined by dominant genera such as Cutibacterium and Staphylococcus, whereas rare commensals remain poorly understood. In this study, we identified Rothia kristinae BF00107, a skin-resident strain with a complete pantothenate biosynthesis pathway, as a novel postbiotic candidate with distinct dermatological benefits. BF00107 fermentation filtrate suppressed pro-inflammatory cytokines (IL-1β and TNF-α) in keratinocytes and restored extracellular matrix homeostasis in UVB-irradiated fibroblasts by upregulating COL1A1 expression and reducing MMP-1 levels. Consistent with the observed phenotypes, transcriptomic profiling revealed a strain-specific signature characterized by downregulation and upregulation of the expression of inflammatory mediators and barrier- and ECM-associated genes, respectively. Comparative genomics and metabolite profiling confirmed BF00107 as a unique high-pantothenate producer. Supplementation with pantothenic acid reproduced the anti-inflammatory and barrier-supporting effects of the strain, confirming its role as a key effector metabolite. Furthermore, BF00107 passed standard safety assessments, including the Human Repeat Insult Patch Test (HRIPT), Ames, and irritation tests, supporting its suitability for human applications. These findings establish the pantothenate-producing R. kristinae BF00107 as the first functionally validated Rothia strain with anti-inflammatory and photoaging-protective properties. This study expands the functional scope of the skin microbiome and highlights rare commensals as valuable reservoirs for safe, strain-specific postbiotic development.

Androgenetic alopecia (AGA) is the most common form of patterned hair loss, exhibiting gender-specific clinical features. Recent studies highlight the importance of the skin microbiome in maintaining skin health, but the relationship between the hair follicle microbiome and hair loss, particularly AGA, remains understudied. Hair follicle layer samples were collected directly from the crown region of female pattern hair loss (FPHL), male pattern hair loss (MPHL), and healthy adult women (control) groups. Microbial DNA was extracted and analyzed using Illumina 16S rRNA V3–V4 gene amplicon sequencing. Alpha-diversity and beta-diversity analyses and taxonomic and functional profiling were conducted through relative abundance, LEfSe, and PICRUSt2 analyses. The alpha-diversity analysis showed a significant decrease in microbial richness in the hair loss groups. Unweighted UniFrac-based beta-diversity analysis revealed significant clustering between the control group and the FPHL group. Taxonomic profiling and LEfSe analysis identified differences in microbial composition and biomarkers. PICRUSt2 analysis further revealed altered pathways related to porphyrin metabolism, fatty acid biosynthesis, and steroid hormone metabolism. Additionally, differences in microbiome composition and potential functions were found between the FPHL and MPHL groups. This study provides comprehensive insights into the hair follicle microbiome, revealing unique microbial patterns and functional alterations associated with FPHL. Understanding these microbiome characteristics may contribute to targeted approaches for addressing AGA. Further research is warranted.

Recognized as the third-generation biomass of the future, microalgae are increasingly viewed as a promising solution for the sustainable production of biofuels, often referred to as “green gold.” Extensive research is being conducted across the upstream, midstream, and downstream sectors to develop fundamental technologies that enable efficient and economical large-scale microalgae cultivation. Recent studies suggest that microalgae-based biofuels have the potential to meet global energy demands. However, challenges such as spatial constraints in site selection and the high cost of transporting CO₂—an essential component for pH regulation and photosynthesis—pose obstacles. Here, this study demonstrates that by supplementing air-only medium with CaCO₃, Chlorella sorokiniana can effectively utilize airborne CO₂ to produce biomass. In laboratory-scale culture conditions supplied only with air, adding 5 mM CaCO₃ (pH 7.8) could maintain the pH stably compared to the untreated conditions (pH 9.5) and improved the biomass concentration and lipid content by 17.68-fold and 9.58-fold, respectively. In bench-scale conditions, cultures supplemented with 5 mM CaCO₃ exhibited a 9-fold increase in the biomass and a 7.15-fold increase in the lipid concentrations compared to those cultivated with air alone. With microalgae emerging as an essential resource for future generations, cultivation technology utilizing CaCO₃ will be a critical technology that enables commercial-scale microalgae cultivation using only air, without artificial CO₂ supply facilities.

Various bacterial strains with nitrate-reducing capacity (NRC), such as Haemophilus, Actinomyces, and Neisseria, are known to promote NH₃ production, control pH in the oral cavity, and inhibit the growth of aciduric bacteria. However, experimental evidence on various estimated bacterial networks within the salivary microbiome is insufficient. This study aims to explore potential bacterial compositional competition observed within saliva samples from dental caries patients through a co-culture assay of mitis Streptococci, which is a primary colonizer in the salivary microbiome, and nitrate-reducing bacteria Haemophilus parainfluenzae. We investigated bacterial growth efficiency change by co-culture time using the qRT-PCR method. In addition, we applied LC/Q-TOF-based metabolites screening to confirm metabolic interactions between oral bacterial species and their association with dental caries from a metabolomics perspective. As a result, we first found that the nitrate reduction ability of H. parainfluenzae is maintained even in a co-culture environment with the mitis Streptococci group through a nitrate reduction test. However, nitrate reduction efficiency was hindered when compared with monoculture-based nitrate reduction test results. Next, we designed species-specific primers, and we confirmed by qRT-PCR that there is an obvious competitive relationship in growth efficiency between H. parainfluenzae and two mitis Streptococci (S. australis and S. sanguinis). Furthermore, although direct effects of nitrate reduction on competition have not been identified, we have potentially confirmed through LC/Q-TOF-based metabolite screening analysis that the interaction of various metabolic compounds synthesized from mitis Streptococci is driving inter-strain competition. In particular, we constructed a basic reference core-metabolites list to understand the metabolic network between each target bacterial species (H. parainfluenzae and mitis Streptococci) within the salivary microbiome, which still lacks accumulated research data. Ultimately, we suggest that our data have potential value to be referenced in further metagenomics and metabolomics-based studies related to oral health care.

The rhizosphere is the area of the soil affected by plant roots and plays an important role in plant health, nutrient cycling, and soil structure. This study investigated differences in rhizosphere soil metabolites between trees in urban and forest environments using LC/MS-Q-TOF and GC/MS. Urban environments can cause soil pollution and ecosystem disturbance due to the accumulation of heavy metals and petrochemicals, while forest environments are rich in organic matter and fallen leaves, maintaining a nutrient-rich environment in which various microorganisms coexist. Rhizosphere soil samples were collected from Dankook University (city) and Taejo Mountain (forest) in Cheonan, South Korea, extracted using methanol and chloroform using the Soxhlet extraction method, and then analyzed by LC/MS-Q-TOF and GC/MS. N-Nitrosopyrrolidine, a possible carcinogen from automobile exhaust and industrial activities, has been found in the rhizosphere soil of urban trees. Forest rhizosphere samples showed high concentrations of momilactone A, which is important for plant defense mechanisms. 140 significant metabolites were identified through MPP analysis. Furthermore, GC/MS analysis confirmed that siloxanes and oleamides were predominantly detected in urban and forest samples, respectively. Overall, this study highlights the impact of environmental conditions on rhizosphere soil chemistry and microbial ecosystems and provides insights for urban greening and forest conservation strategies. Comprehensive profiling of rhizosphere metabolites will improve our understanding of plant-soil interactions and contribute to maintaining soil health and plant diversity in diverse ecosystems.