• Journal of Microbiology and Biotechnology
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• v.31 no.9
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• pp.1231-1240
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• 2021

Members of the genus Bacillus are known to play an important role in promoting plant growth and protecting plants against phytopathogenic microorganisms. In this study, 21 isolates of Bacillus spp. were obtained from the root micro-ecosystem of Suaeda glauca. Analysis of the 16S rRNA genes indicated that the isolates belong to the species Bacillus amyloliquefaciens, Bacillus velezensis, Bacillus subtilis, Bacillus pumilus, Bacillus aryabhattai and Brevibacterium frigoritolerans. One of the interesting findings of this study is that the four strains B1, B5, B16 and B21 are dominant in rhizosphere soil. Based on gyrA, gyrB, and rpoB gene analyses, B1, B5, and B21 were identified as B. amyloliquefaciens and B16 was identified as B. velezensis. Estimation of antifungal activity showed that the isolate B1 had a significant inhibitory effect on Fusarium verticillioides, B5 and B16 on Colletotrichum capsici (syd.) Butl, and B21 on Rhizoctonia cerealis van der Hoeven. The four strains grew well in medium with 1-10% NaCl, a pH value of 5-8, and promoted the growth of Arabidopsis thaliana. Our results indicate that these strains may be promising agents for the biocontrol and promotion of plant growth and further study of the relevant bacteria will provide a useful reference for the development of microbial resources.

• Journal of Food Hygiene and Safety
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• v.29 no.1
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• pp.40-46
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• 2014

We have screened Bacillus strains suitable for the fermentation of soybean products with respect to the control of Bacillus cereus and the reduction of biogenic amines. Of 26 isolates, a strain named as the SCK A08 carried antimicrobial activity against B. cereus and Staphylococcus aureus, major food poisoning species in soybean products. PCR analysis revealed that the SCK A08 strain did not contain genes for Bacillus cereus toxins including nonhemolytic enterotoxin, hemolytic enterotoxin, cytotoxin K, cereulide and certrax. The SCK A08 strain could degrade histamine, tyramine, putrescine, and cadaverine by 67.41%, 76.59%, 57.32%, and 50.69%, respectively, during fermentation in cooked soybeans containing 0.5% (w/w) of each biogenic amine. The morphological and biochemical properties and phylogenetic relationships based on 16S rRNA gene sequences indicated that the isolate was most closely related to Bacillus licheniformis. Use of the strain SCK A08 would be a potential measure to overcome two hygienic problems that were frequently faced during manufacture of traditionally fermented soybean products.

• Korean Journal of Food Science and Technology
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• v.46 no.2
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• pp.153-164
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• 2014

Five takju prepared using four types of nuruk (a traditional Korean fermentation starter made of malted wheat; non-cooked, naturally inoculated) labeled SH, SS, JJ, and SJ, and one type of koji (cooked, inoculated with an inoculum) labeled MN, were compared. Titratable acidity, pH, sugars, ethanol, amino acids, organic acids, and microbial changes in samples were measured, and the sensory properties were evaluated. Titratable acidity, alcohol, and organic acid content increased as sugar contents decreased. The overall ethanol concentration of all takju increased over time, reaching a maximum of 13.08-14.96% (w/v) at 7-21 days. The total amino acid contents of takju prepared with nuruk, except for one (SJ), were higher than the takju prepared with koji (MN). Lactic acid bacteria were also isolated from the starters. Sequence analysis of 16S rRNA genes (500 - 600 bp) of 223 isolates revealed that the major strains were in the genera of Leuconostoc, Weissella, Pediococcus, and Lactobacillus.

• Journal of Ginseng Research
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• v.45 no.2
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• pp.316-324
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• 2021

Background: Korea Red Ginseng (KRG) has been used as remedies with hepato-protective effects in liver-related condition. Microbiota related gut-liver axis plays key roles in the pathogenesis of chronic liver disease. We evaluated the effect of KRG on gut-liver axis in patients with nonalcoholic statohepatitis by the modulation of gut-microbiota. Methods: A total of 94 patients (KRG: 45 and placebo: 49) were prospectively randomized to receive KRG (2,000 mg/day, ginsenoside Rg1+Rb1+Rg3 4.5mg/g) or placebo during 30 days. Liver function test, cytokeraton 18, and fatigue score were measured. Gut microbiota was analyzed by MiSeq systems based on 16S rRNA genes. Results: In KRG group, the mean levels (before vs. after) of aspartate aminotransferase (53 ± 19 vs. 45 ± 23 IU/L), alanine aminotransferase (75 ± 40 vs. 64 ± 39 IU/L) and fatigue score (33 ± 13 vs. 26 ± 13) were improved (p < 0.05). In placebo group, only fatigue score (34 ± 13 vs. 31 ± 15) was ameliorated (p < 0.05). The changes of phyla were not statistically significant on both groups. In KRG group, increased abundance of Lactobacillus was related with improved alanine aminotransferase level and increased abundance of Clostridium and Intestinibacter was associated with no improvement after KRG supplementation. In placebo group, increased abundance of Lachnospiraceae could be related with aggravation of liver enzyme (p < 0.05). Conclusion: KRG effectively improved liver enzymes and fatigue score by modulating gut-microbiota in patients with fatty liver disease. Further studies are needed to understand the mechanism of improvement of nonalcoholic steatohepatitis. ClnicalTrials.gov: NCT03945123 (www.ClinicalTrials.gov).

• Journal of Microbiology and Biotechnology
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• v.33 no.10
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• pp.1292-1298
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• 2023

PAMB 00755^T, a bacterial strain, was isolated from Korean fir leaves. The strain exhibits yellow colonies and consists of Gram-negative, non-motile, short rods or ovoid-shaped cells. It displays optimal growth conditions at 20℃, 0% NaCl, and pH 6.0. Results of 16S rRNA gene-based phylogenetic analyses showed that strain PAMB 00755^T was most closely related to Sphingomonas chungangi MAH-6^T (97.7%) and Sphingomonas polyaromaticivorans B2-7^T (97.4%), and ≤96.5% sequence similarity to other members of the genus Sphingomonas. The values of average nucleotide identity (79.9-81.3%), average amino acid identity (73.3-75.9%), and digital DNA-DNA hybridization (73.3-75.9%) were significantly lower than the threshold values for species boundaries; these overall genome-related indexes (OGRI) analyses indicated that the strain represents a novel species. Genomic analysis revealed that the strain has a 4.4-Mbp genome encoding 4,083 functional genes, while the DNA G+C content of the whole genome is 66.1%. The genome of strain PAMB 00755^T showed a putative carotenoid biosynthetic cluster responsible for its antioxidant activity. The respiratory quinone was identified as ubiquinone 10 (Q-10), while the major fatty acids in the profile were identified as C_18:1ω7c and/or C_18:1ω6c (summed feature 8). The major polar lipids of strain PAMB 00755^T were diphosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid, and phosphatidylcholine. Based on a comprehensive analysis of genomic, phenotypic, and chemotaxonomic characteristics, we proposed the name Sphingomonas abietis sp. nov. for this novel species, with PAMB 00755^T as the type strain (= KCTC 92781^T = GDMCC 1.3779^T).