Lactic acid bacteria (LAB) and qualified presumption of safety (QPS)-designated Bacillus strains are widely applied to enhance the nutritional and functional properties of natural products. Green garlic (Allium sativum L.), a common Korean vegetable and recognized functional food, is valued for its antioxidant and immune-enhancing activities. In this study, we investigated the functional properties of green garlic fermented with LAB and QPS-designated Bacillus strains. A total of 450 strains were isolated from marine environments, livestock sources, and diverse agricultural and fishery products, including fermented derivatives, of which 191 originated from agricultural products. Enzyme assays identified 89 strains with strong protease and amylase activities. After excluding taxonomic duplicates, we obtained seven QPS-designated Bacillus strains and four LAB strains characterized by robust growth in media containing green garlic. Fermentation using Sacheon green garlic powder was conducted for 4 days, and compared with the control, we found that the antioxidant activity of green garlic fermented with Latilactobacillus curvatus GH-11-11 and Bacillus amyloliquefaciens JY-48-5 increased by 144.0% and 145.8%, respectively. In addition, relative to a non-fermented extract, a 2-day fermentation with JY-48-5 enhanced α-glucosidase inhibitory activity by over 189.4%. These findings indicate that cultures of selected LAB and QPS-designated Bacillus strains could serve as promising starters for enhancing the bioactive properties of foods, and also emphasize the importance of regional microbial resources.

The lactic acid bacteria, Lactiplantibacillus plantarum KU15149 and Levilactobacillus brevis KU15176 were verified through phenotypic and genotypic analyses. Safety evaluation was conducted using multiple assays, including minimum inhibitory concentration assay for nine antibiotics, hemolytic activity, mucin degradation, gelatin liquefaction, urease activity, indole production, β-glucuronidase activity, bile salt deconjugation, cell cytotoxicity, D-/L-lactic acid production, and biogenic amine formation. Genotypically L. plantarum KU15149 and L. brevis KU15176 lacked all virulence and antibiotic resistance genes investigated. Consistent with these results, phenotypic assays showed that both strains were susceptible according to EFSA cut-off values and tested negative for hemolysis, mucin degradation, gelatin liquefaction, urease activity, indole production, β-glucuronidase activity, and bile salt deconjugation. Furthermore, neither strain showed cytotoxicity toward Caco-2 cells at a multiplicity of infection of 250. Production of D-lactic acid and biogenic amines was negligible in both bacteria. Overall, L. plantarum KU15149 and L. brevis KU15176 demonstrated safety and beneficial characteristics and therefore could serve as probiotic strains.

This study aimed to confirm the species identity and characterize two Selenomonas sputigena strains (KCOM 1787 and KCOM 2046) isolated from the oral cavities of Korean individuals using genomic and chemotaxonomic approaches. Whole-genome sequencing was performed with PacBio RSII and Illumina platforms. Species-level classification was assessed using 16S rDNA similarity, average nucleotide identity (OrthoANI), and genome-togenome distance calculation (GGDC). Chemotaxonomic analysis included cellular fatty acid profiling using gas chromatography and polar lipid analysis using two-dimensional thin-layer chromatography. The two strains showed 16S rDNA similarities of 98.85% and 99.53% with the S. sputigena type strain ATCC 35185T. OrthoANI values exceeded the species threshold (95.34% and 95.69%), whereas GGDC values were below the conventional cutoff (61.6% and 63.7%). Despite the low GGDC values, classification as S. sputigena was supported by the combined evidence of high 16S similarity, OrthoANI values above the species demarcation threshold, and minimal differences in genomic GC content (< 1 mol%). Chemotaxonomic analysis revealed that the major fatty acids were C14:0 DMA and C16:1 cis -7, while the polar lipids included phosphatidylethanolamine and several unidentified aminolipids. Although GGDC values were below the 70% species threshold, the high OrthoANI values, 16S rDNA similarity, and genomic GC content supported the classification of KCOM 1787 and KCOM 2046 as S. sputigena. These strains may serve as valuable resources for future studies on intraspecies variation and the pathogenesis of oral Selenomonas species.

Wood ear mushrooms (Auricularia heimuer) are commercially used in various fields in South Korea. Therefore, it is necessary to take appropriate measures, including monitoring and prevention of microbial growth in cultivation houses, as microorganisms can reduce the wood ear mushroom’s marketability and cause food poisoning among consumers. Therefore, this study was conducted to evaluate the direct impact of airborne fungi isolated and identified from the indoor air of domestic wood ear mushroom cultivation houses on the mycelia growth of wood ear mushroom strains. For the evaluation, 11 airborne fungal species were tested with three strains of A. heimuer on PDA using the cocultivation method. Among them, Alternaria alternata, Cladosporium anthropophilum, Cochliobolus kusanoi, Lecanicillium sp., Periconia byssoides, and Periconia pseudobyssoides suppressed the mycelial growth of all three A. heimuer strains. There was no significant difference in the reaction against the 11 tested airborne fungal species among the three A. heimuer strains. The results of this study show that proper management of airborne fungi is necessary in the indoor environment of wood ear mushroom cultivation houses.

Three strains (KCOM 2191, KCOM 2668, and KCOM 2812) of Capnocytophaga sp. isolated from a Korean population were initially classified by 16S rDNA sequence comparison. This study aimed to resolve their species-level identity using whole genome sequencing and to assess their taxonomic characteristics. Genomes of the three strains were sequenced using PacBio RS II and Illumina platforms. Average nucleotide identity (ANI) analysis was employed for species-level identification. Cellular fatty acid (CFA) compositions were determined using the MIDI/Hewlett Packard Microbial Identification System. ANI values for KCOM 2191, KCOM 2668, and KCOM 2812 were 96.43%, 96.33%, and 96.33%, respectively, compared with the type strain Capnocytophaga ochracea DSM 7271T. CFA profiling showed a predominance of iso-C15:0 (57.9%, 67.2%, and 64.9%, respectively), consistent with DSM 7271T (51.5%). These findings confirm that KCOM 2191, KCOM 2668, and KCOM 2812 are strains of C. ochracea . These strains may serve as valuable models for investigating the role of C. ochracea in oral and systemic pathogenesis.

The Grifola frondosa cultivar KMCC03118 was used to isolate monokaryotic strains via spore separation, resulting in the successful crossbreeding of strains KMCC03118-11 and KMCC03118-23, which produced F1 hybrids. These F1 hybrids were then further crossed with various monokaryotic strains to generate F2 progeny. In evaluating the effects of different medium compositions on fruit body development, it was found that a substrate consisting of wheat bran and dried sawdust, with a carbon-to-nitrogen (C/N) ratio of 66-68, provided the most favorable conditions for mycelial growth. Among the strains tested, KMCC03137 and GF-18-50 demonstrated superior characteristics, including a larger fruit body diameter, thicker pileus, and greater stipe thickness, with the highest productivity observed at 143.6 ± 13.3 g and 144.7 ± 15.2 g, respectively. Furthermore, the color of the caps (L: 29.7 ± 7.1, a: 2.6 ± 0.7, b: 8.2 ± 1.8) remained consistent, indicating stable high-quality production. Based on these results, the optimal substrate composition for enhancing both the quality and productivity of the fruit bodies was determined to be 42% Quercus sp. sawdust, 42% Quercus sp. fermented sawdust, 6% wheat bran, and 10% dried tofu residue. This study provides a crucial foundation for the commercial cultivation and breeding improvement of Grifola frondosa, offering valuable insights into its genetic enhancement, and providing essential data for future research aimed at increasing the species' genetic diversity and productivity.

Probiotic lactic acid bacteria are live microorganisms that provide health benefits when administered in adequate amounts and may exhibit antiproliferative effects on various cancer cell lines, including colon cancer. This study investigates the cytotoxic effects of three Lactobacillus strains - Limosilactobacillus (L.) reuteri VA 102, Ligilactobacillus (L.) animalis VA 105, and Limosilactobacillus (L.) reuteri KCTC 3594 (ATCC 23272) - on mouse colon carcinoma cells (CT-26). Live cells, heat-killed cells, and cell-free supernatant (CFS) of Lactobacillus sp. were prepared and used to treat CT-26 cells at different concentrations. The cytotoxic effect was assessed using the MTT assay. The results indicated that the CFS of all strains significantly reduced the viability of CT-26 cells in a dose-dependent manner, with the VA 102 strain showing the most pronounced effect. Heat-killed cells of L. reuteri VA 102 and L. reuteri KCTC 3594 (ATCC 23272) also reduced cell viability. These findings suggest the potential anticancer properties of these Lactobacillus strains and indicate that CFS and heat-killed cells may offer a safer and more effective alternative to live bacteria for therapeutic applications. Our study contributes to the understanding of the potential of Lactobacillus strains, particularly L. reuteri VA 102, L. reuteri KCTC 3594 (ATCC 23272), and L. animalis VA 105, as possible candidates for cancer treatment and control.

Entomopathogenic fungi have been studied to control insect pests as an alternative to chemical insecticides. However, all fungi haven't a high virulence against pests. In this study, we compared the biological characteristics of Metarhizium anisopliae strains. First, we selected four M. anisopliae strains and compared the thermotolerance, conidial productivity, and virulence. For the thermotolerance test, conidial suspensions were exposed to 0, 30, 60, and 90 min at 45 °C. As a result, the conidial germination rates were over 95% when exposed for 0 min but, were 64, 37.7, 6, and 3% when exposed for 30 min at 45°C, respectively. To compare conidial productivity, 200g of millet were used and inoculated with a conidial suspension of 1 ml (1×107 conidia/ml). Conidial productivity was investigated after 14 days. As a result of conducting a virulence test against mealworms using a spray method, differences in virulence between strains were confirmed.