• Food Science and Preservation
• /
• v.24 no.8
• /
• pp.1168-1179
• /
• 2017

In this study, we tried to screen the Bacillus strain having safety probability by isolation of strains from traditional fermented food, measurement of probiotic properties, and the fermentative characteristics of Cheonggukjang. We isolated 400 Bacillus-like isolates from traditional fermented foods. Selected strains examined on the prevalent characteristic such as extracellular enzyme and antibacterial activities, and their safety probability was confirmed by biogenic amine productivity, hemolytic, and harmful substances and enzyme productivity. We selected the 5 strains by analysis of biogenic amine, antibacterial and B. cereus toxic associated gene. Five selected strains were examined on cell surface hydrophobicity, and bile and acid tolerance, and we selected the SRCM100730 as the final strain. SRCM100730 was confirmed B. amyloliquefaciens by 16S rRNA sequencing, and named the B. amyloloquefaciens SRCM100730 (KCCM11966P). Finally, we manufactured Cheonggukjang using SRCM100730 for confirmation of fermentation properties. Manufactured Cheonggukjang did not contain B. cereus, and showed that ${\gamma}$-PGA and extracellular enzyme activities were superior to commercial Chunggukjang. Amino nitrogen content was 544.02 mg% and 26 free amino acid were detected, and the bitterness-related amino acid content was lower than commercial Cheonggukjang. Especially, the amount of GABA was 3 fold higher than commercial Cheonggukjang. These results suggest that SRCM100730 have high availability in commercial probiotics market and fermented food industry.

• Microbiology and Biotechnology Letters
• /
• v.48 no.1
• /
• pp.57-63
• /
• 2020

Over the past 20 years, global warming has transformed the marine ecosystem of the Jeju Island into a subtropical zone making it conducive to the production of tropical fishes. Recently, the balloon fish (Diodon holoanthus) has been found off the coast of the Jeju Island. In this study, we analyzed the diversity of its intestinal microorganisms as a representative for the surrounding environment. In addition, the isolates were evaluated for their antibacterial activity. A total of 161 strains of various species were identified and isolated using 16S ribosomal RNA gene sequence analysis. They were separated into three groups, of which Phylum Proteobacteria was found to be the most dominant with 91% sequence similarity. This includes the class γ-proteobacteria that is made up of twelve genera and twenty-four hundred species. The second group comprised strains of the genus Vibrio, made up of 35% Photobacteria, 32% Shewanella, and 6% Psychrobacter. It was also determined that 4% of the isolates were Acinetobacter, 3% were Enterovibrio, while Moraxella_g2 accounted for 1% of the total isolates. Class α-proteobactera includes five genera and five species; Brevundimonas, Allorhizobium, Pseudoceanicola and Erythrobcter, each accounting for 1% of the total isolates. The Firmicute strains belonged to six genera and ten species. 5% of the strains were Terribacillus, while Paenibacillus, Salinicoccus, Staphylococcus and Streptococcus accounted for 1% each of the total isolates. Actinobacteria accounted for the final phylum with strains belonging to three genera and ten species with Janibacter, Micrococcus and Isoptericola each accounting for 1% of the total isolates.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.10
• /
• pp.1644-1655
• /
• 2019

Saccharomyces cerevisiae (S. cerevisiae) and glucagon-like peptide-2 (GLP-2) have been employed to improve the intestinal development of weaned animals. The goal of this study was to determine whether either exogenous S. cerevisiae or GLP-2 elicits major effects on fecal microbiotas and cytokine responses in weaned piglets. Ninety-six piglets weaned at 26 days were assigned to one of four groups: 1) Basal diet (Control), 2) empty vector-harboring S. cerevisiae (EV-SC), 3) GLP-2-expressing S. cerevisiae (GLP2-SC), and 4) recombinant human GLP-2 (rh-GLP2). At the start of the post-weaning period (day 0), and at day 28, fecal samples were collected to assess the bacterial communities via sequencing the V1-V2 region of the 16S-rRNA gene, and piglets' blood was also sampled to measure cytokine responses (i.e., IL-$1{\beta}$, TNF-${\alpha}$, and IFN-${\gamma}$). This study revealed that, on the one hand, although S. cerevisiae supplementation did not significantly alter the growth of weaned piglets, it induced increases in the relative abundances of two core genera (Ruminococcaceae_norank and Erysipelotrichaceae_norank) and decreases in the relative abundances of two other core genera (Lachnospiraceae_norank and Clostridiale_norank) and cytokine levels (IL-$1{\beta}$ and TNF-${\alpha}$) (p < 0.05, Control vs EV-SC; p < 0.05, rh-GLP2 vs GLP2-SC). On the other hand, GLP-2 supplementation had no significant influence on fecal bacterial communities and cytokine levels, but it produced better body weight and average daily gain (p < 0.05, Control vs EV-SC; p < 0.05, rh-GLP2 vs GLP2-SC). Therefore, altered fecal microbiotas and cytokine response effects in weaned piglets were due to S. cerevisiae rather than GLP-2.

• Journal of Ginseng Research
• /
• v.47 no.5
• /
• pp.627-637
• /
• 2023

Background: Damage to the healthy intestinal epithelial layer and regulation of the intestinal immune system, closely interrelated, are considered pivotal parts of the curative treatment for inflammatory bowel disease (IBD). Plant-based diets and phytochemicals can support the immune microenvironment in the intestinal epithelial barrier for a balanced immune system by improving the intestinal microecological balance and may have therapeutic potential in colitis. However, there have been only a few reports on the therapeutic potential of plant-derived exosome-like nanoparticles (PENs) and the underlying mechanism in colitis. This study aimed to assess the therapeutic effect of PENs from Panax ginseng, ginseng-derived exosome-like nanoparticles (GENs), in a mouse model of IBD, with a focus on the intestinal immune microenvironment. Method: To evaluate the anti-inflammatory effect of GENs on acute colitis, we treated GENs in Caco2 and lipopolysaccharide (LPS) -induced RAW 264.7 macrophages and analyzed the gene expression of proinflammatory cytokines and anti-inflammatory cytokines such as TNF-α, IL-6, and IL-10 by real-time PCR (RT-PCR). Furthermore, we further examined bacterial DNA from feces and determined the alteration of gut microbiota composition in DSS-induced colitis mice after administration of GENs through 16S rRNA gene sequencing analysis. Result: GENs with low toxicity showed a long-lasting intestinal retention effect for 48 h, which could lead to effective suppression of pro-inflammatory cytokines such as TNF-α and IL-6 production through inhibition of NF-κB in DSS-induced colitis. As a result, it showed longer colon length and suppressed thickening of the colon wall in the mice treated with GENs. Due to the amelioration of the progression of DSS-induced colitis with GENs treatment, the prolonged survival rate was observed for 17 days compared to 9 days in the PBS-treated group. In the gut microbiota analysis, the ratio of Firmicutes/Bacteroidota was decreased, which means GENs have therapeutic effectiveness against IBD. Ingesting GENs would be expected to slow colitis progression, strengthen the gut microbiota, and maintain gut homeostasis by preventing bacterial dysbiosis. Conclusion: GENs have a therapeutic effect on colitis through modulation of the intestinal microbiota and immune microenvironment. GENs not only ameliorate the inflammation in the damaged intestine by downregulating pro-inflammatory cytokines but also help balance the microbiota on the intestinal barrier and thereby improve the digestive system.

• Journal of Life Science
• /
• v.25 no.12
• /
• pp.1408-1414
• /
• 2015

In this study, to retain a stable bacterial inoculant, Bacillus strains showing antifungal activity were screened. The improved production, antifungal mechanism, and stability of the antifungal metabolite by a selected strain, AF4, a potent antagonist against phytopathogenic Botrytis cinerea, were also investigated. The AF4 strain was isolated from rhizospheric soil of hot pepper and identified as Bacillus subtilis by phenotypic characters and 16S rRNA gene analysis. Strain AF4 did not produce antifungal activity in the absence of a nitrogen source and produced antifungal activity at a broad range of temperatures (25-40℃) and pH (7-10). Optimal carbon and nitrogen sources for the production of antifungal activity were glycerol and casein, respectively. Under improved conditions, the maximum antifungal activity was 140±3 AU/ml, which was higher than in the basal medium. Photomicrographs of strain AF4-treated B. cinerea showed morphological abnormalities of fungal mycelia, demonstrating the role of the antifungal metabolite. The B. subtilis AF4 culture exhibited broad antifungal activity against several phytopathogenic fungi. The antifungal activity was heat-, pH-, solvent-, and protease-stable, indicating its nonproteinous nature. These results suggest that B. subtilis AF4 is a potential candidate for the control of phytopathogenic fungi-derived plant diseases.

• Journal of Life Science
• /
• v.34 no.5
• /
• pp.304-312
• /
• 2024

This study was conducted to characterize strain Y10, isolated from discarded chicken feathers. Strain Y10 was identified as Bacillus amyloliquefaciens through phenotypic and 16S rRNA gene analysis. B. amyloliquefaciens Y10 exhibited plant growth-promoting activities, including the production of fungal cell-degrading enzymes (cellulase, lipase, protease, and pectinase), siderophores, ammonia, and indoleacetic acid. Furthermore, strain Y10 was able to inhibit the mycelial growth of several phytopathogenic fungi. When 0.1% sucrose as a carbon source and 0.05% casein as a nitrogen source were added to the basal medium, adjusted to pH 10, and cultured at 35℃, the degradation rate of chicken feathers by strain Y10 was about two times higher than that of the basal medium, with the feathers almost completely degraded in four days. Strain Y10 also degraded various keratin substrates, including duck feathers, wool, and human nails. It was confirmed that the feather hydrolyzates prepared using strain Y10 exhibited antioxidant activities, such as 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (EC₅₀ = 0.38 mg/ml) and superoxide dismutase-like activity (EC₅₀ = 183.7 mg/ml). These results suggest that B. amyloliquefaciens Y10 is a potential candidate for the development of bioinoculants and feed additives applicable to the agricultural and livestock industries, as well as the microbiological treatment of keratin waste.

• Mycobiology
• /
• v.45 no.3
• /
• pp.160-171
• /
• 2017

Larvae of Bradysia agrestis, an insect vector that transports plant pathogens, were sampled from geographically isolated regions in Korea to identify their cutaneous fungal and bacterial flora. Sampled areas were chosen within the distribution range of B. agrestis; each site was more than 91 km apart to ensure geographical segregation. We isolated 76 microbial (fungi and bacteria) strains (site 1, 29; site 2, 29; site 3, 18 strains) that were identified on the basis of morphological differences. Species identification was molecularly confirmed by determination of universal fungal internal transcribed spacer and bacterial 16S rRNA gene sequences in comparison to sequences in the EzTaxon database and the NCBI GenBank database, and their phylogenetic relationships were determined. The fungal isolates belonged to 2 phyla, 5 classes, and 7 genera; bacterial species belonged to 23 genera and 32 species. Microbial diversity differed significantly among the geographical groups with respect to Margalef's richness (3.9, 3.6, and 4.5), Menhinick's index (2.65, 2.46, and 3.30), Simpson's index (0.06, 0.12, and 0.01), and Shannon's index (2.50, 2.17, and 2.58). Although the microbial genera distribution or diversity values clearly varied among geographical groups, common genera were identified in all groups, including the fungal genus Cladosporium, and the bacterial genera Bacillus and Rhodococcus. According to classic principles of co-evolutionary relationship, these genera might have a closer association with their host insect vector B. agrestis than other genera identified. Some cutaneous bacterial genera (e.g., Pseudomonas) displaying weak interdependency with insect vectors may be hazardous to agricultural environments via mechanical transmission via B. agrestis. This study provides comprehensive information regarding the cutaneous microflora of B. agrestis, which can help in the control of such pests for crop management.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.7
• /
• pp.909-914
• /
• 2023

While searching for the bacteria which are responsible for degradation of pesticide in soybean field soil, a novel bacterial strain, designated 5-5^T, was isolated. The cells of the strain were Gram-staining-positive, aerobic and non-motile rods. Growth occurred at 10-42℃ (optimum, 30℃), pH 5.5-9.0 (optimum, pH 7.0-7.5), and 0-2% (w/v) NaCl (optimum, 1%). The predominant fatty acids were C_15:0 anteiso, C_17:0 anteiso, and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). The predominant menaquinone was MK-9 (H₂). Diphosphatidylglycerol, glycolipids, phosphatidylinositol, and phosphatidylglycerol were the major polar lipids. Phylogenetic analysis of 16S rRNA gene sequences indicated that strain 5-5^T is a member of the genus Sinomonas and its closest relative is Sinomonas humi MUSC 117^T, sharing a genetic similarity of 98.4%. The draft genome of strain 5-5^T was 4,727,205 bp long with an N50 contig of 4,464,284 bp. Genomic DNA G+C content of strain 5-5^T was68.0 mol%. The average nucleotide identity (ANI) values between strain 5-5^T and its closest strains S. humi MUSC 117^T and S. susongensis A31^T were 87.0, and 84.3 % respectively. In silico DNA-DNA hybridization values between strain 5-5^T and its closest strains S. humi MUSC 117^T and S. susongensis A31^T were 32.5% and 27.9% respectively. Based on the ANI and in silico DNA-DNA hybridization analyses, the 5-5^T strain was considered as novel species belonging to the genus Sinomonas. On the basis of the results from phenotypic, genotypic and chemotaxonomic analyses, strain 5-5^T represents a novel speciesof the genus Sinomonas, for which the name Sinomonas terrae sp. nov. is proposed. The type strain is 5-5^T (=KCTC 49650^T =NBRC 115790^T).

• Korean Journal of Poultry Science
• /
• v.51 no.2
• /
• pp.73-82
• /
• 2024

The gut microbiome of broilers is a critical factor in overall health and productivity. However, high summer temperatures and high stocking density (conventional farm condition) may cause stress to broilers, resulting in an imbalance in the gut microbiome. This study was conducted to compare the gut microbiome of broilers between spring and summer in welfare (Bosung, Jeollanam-do, South Korea) and conventional farms (Jangsu, Jeollabuk-do, South Korea). A total of 31 broilers were assigned to the following groups: conventional farm in spring (n = 8); conventional farm in summer (n = 8); welfare farm in spring (n = 7); welfare farm in summer (n = 8). Cecal digesta were collected from eight broilers from each farm, and microbiome analysis was performed using 16S rRNA gene sequencing. Beta diversity analysis indicated clear differences in cecal microbiome composition between spring and summerin both welfare and conventional farm. At the phylum level, analysis of conventional farm revealed a higher proportion of Bacteroidetes in spring than in summer. At the genus level, broilers exhibited a higher abundance of Bacteroides and Alistipesin spring compared to summer. In contrast, the difference in microbial flora composition observed in welfare farm was relatively small compared to conventional farm. In conclusion, the results of this study suggest that heat stress can negatively affect the caecum microbiome of broilers. However, improvements in the housing environment can mitigate the effects of heat stress.

• Food Science and Preservation
• /
• v.18 no.6
• /
• pp.973-979
• /
• 2011

The grape cultivar Campbell Early has high levels of malic acid as well as tartaric acid. The high concentration of total acid in the Campbell Early wine is a critical aspect of the wine's sensory characteristics. To prevent the deterioration of the wine's quality, which is caused by the strong sour taste derived from the raw material in wine making, the deacidification factor was investigated via carbonic maceration under different temperature conditions, especially in the presence or absence of malolactic bacteria. Based on the results of the presence test of the malolactic bacteria during carbonic-maceration treatment, Lactobacillus brevis, Lactobacillus plantarum, and Streptococcus thermophilus were characterized morphologically and were identified via biochemical tests and 16S-rRNA-gene-sequencing analysis. The isolated strains were found not to consume malic acid and to produce lactic acid. Moreover, these strains were consumed as soluble solids. The isolated strains are popularly known as lactic-acid bacteria and should have produced lactic acid from glucose. The Oenococcus oeni of the malolactic bacteria was not isolated. These results showed that the isolated strains are not deacidified during carbonic-maceration treatment.