• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.377-385
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• 2014

In this study, a wastewater treatment system for hypersaline wastewater utilizing the Hypersaline Wastewater Treatment Community (HWTC) has been developed. The hypersaline wastewater treatment efficiency and microbial community of the HWTC were investigated. The average removal efficiencies of chemical oxygen demand were 84% in an HRT of 2.5 days. Microbial community analysis, by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene fragments and 16S rRNA gene clone library, revealed community diversity. The 16S rRNA gene analysis of dominant microbial bacteria in 4% hypersaline wastewater confirmed the presence of Halomonas sp. and Paenibacillus sp. Phylogenetic analysis suggested that the taxonomic affiliation of the dominant species in the HWTC was ${\gamma}$-proteobacteria and firmicutes. These results indicate the possibility that an appropriate hypersaline wastewater treatment system can be designed using acclimated sludge with a halophilic community.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.367-376
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• 1997

Vibrio vulnificus is a gram-negative, halophilic, oxidase-positive, lactose-positive, motile, rod shaped bacterium that has been associated with primary septicemia and wound infection. Elucidating the growth and survival of V. vulnificus in ecological conditions is of great importance to develop sanitary measure against this microorganism. Thus we simulated the ecological conditions and evaluated the effect. About $10^5\;CFU/ml$ of V. vulnificus was inoculated to fresh water, brackish water $(1\%\;NaCl)$, sea water $(3\%\;NaCl)$, and bottom deposit solution. The same concentration of V. vulnificus was also inoculated to distilled water, $1\%\;NaCl$ solution and $3\%\;NaCl$ solution as controls. These were stored at 4, 15 and $25^{\circ}C$, respectively and were used to assess the effects of temperature and salinity on the survival of V. vulnificus. In fresh water V. vulnificus could not survive regardless of storage temperature. In case of brackish water and sea water survival time of V. vulnificus was the longest at $25^{\circ}C$, and the number of V. vulnificus was decreased most rapidly at $4^{\circ}C$. V. vulnificus survived longer in brackish water than in any other conditions. In bottom deposit solution containing brackish water, the survival time of V. vulnificus was longer and the rate of decline was slower than that in brackish water. These results indicate that both biological and physicochemical factors such as temperature and salinity could affect survival of V. vulnificus. V. vulnificus, damaged in normal fresh water, did not grow on TCBS agar of selective plating medium but grew on BHI agar plate; However, V. vulnificus was recovered by addition of salt and nutrient materials.

• The Journal of Natural Sciences
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• v.14 no.2
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• pp.67-82
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• 2004

A thiol-specific antioxidant protein (TSA or TPx) was purified from Halophilic archeabacteria Halococcus agglomeratus, by DEAE-Cellulose, Phnyl, sepharose, Sephadex G-75, Sephacryl S-100, Sephacryl S-200, and Q-Wepharose FF. This protein exhibited the preventeive effect against the inactivation of glutamine synthehase (GS) activity was support by a thiol-reducing equicalent such as dithiothreitol. TPx activity was maximal at NaCl concentration above 500mM. The molecular mass of the protein was determinated to be 22-kDa by SDS-PAGE. The TPx purified from Halococcus agglomeratus seems to be similar to other TPx family, except for the salt requirement for the maximal antioxidant activity.

• Journal of Microbiology and Biotechnology
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• v.7 no.6
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• pp.423-428
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• 1997

Vibrio vulnificus is a halophilic gram-negative human pathogen, which affects people with underlying liver diseases or a suppressed immune system, often leading to primary septicemia with a mortality rate of higher than 60%. In an effort to develop an oral vaccine against V. vulnificus infection, we prepared a whole cell killed vaccine of V. vulnificus on a large scale and compared the immunogenicity and protective efficacy of the vaccine administered in three formulation forms in rabbits. Since V. vulnificus O-antigen serotypes 1, 2, 3, 4, 5, and 7 account for more than 95% of clinical isolates, we prepared cell lysates from these six serotype strains and mixed in equal amounts for a vaccine. The vaccine was administered to rabbits intramuscularly (i.m.), orally as granules or as enteric-coated granules. In rabbits, all three formulation forms elicited a high level of serum IgG antibody reactive not only to the six strains but also to other O-antigen serotypes 6, 8 and 9, indicating cross-reactivities among the strains. Immunotherapeutic efficacy of the antisera was also evaluated by a passive immunization assay, which revealed that the orally immunized antisera as well as the i.m. immunized antisera was protective against a subsequent lethal challenge of V. vulnificus. These data demonstrate that oral immunization with a V. vulnificus whole cell lysate vaccine induced a systemic immune response and suggest the feasibility of development of this vaccine preparation as an oral vaccine.

• The Korean Journal of Mycology
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• v.45 no.1
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• pp.23-30
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• 2017

Twenty-two yeast strains of 15 species were isolated from the leaves of 20 trees on Oknyeobong Peak, and 24 yeast strains of 12 species were isolated from the leaves of 20 trees on Yeonjasan Mountain in Daejeon city, Korea. Cryptococcus bestiolae (5 strains) and Aureobasidium pullulans (8 strains) were the predominant isolates from Oknyeobong Peak and Yeonjasan Mountain, respectively. Of a total of 46 yeast strains, Cryptococcus kuetzingii JSL508, Cryptococcus vishniacii JSL509, and Dioszegia takashimae JSL510 from Okyeobong Peak, and Plowrightia periclymeni JSL514, Erythrobasidium hasegawanium JSL0193, and Rhodotorula nothofagi JSL0196 from Yeonjasan Mountain were determined to be yeast strains that were yet unrecorded in Korea. Morphological and cultural characteristics of these unrecorded yeasts were investigated. Erythrobasidium hasegawanium JSL0193 and Rhodotorula nothofagi JSL0196 did not form ascospores and pseudomycelia. All the strains, except Dioszegia takashimae JSL510, were halotolerant or halophilic, and Cryptococcus kuetzingii JSL508 and Dioszegia takashimae JSL510 were thermophilic, growing at $37^{\circ}C$.

• Journal of Photoscience
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• v.9 no.3
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• pp.45-48
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• 2002

Microbial rhodopsins, photoactive 7-transmembrane helix proteins that use retinal as their chromophore, were observed initially in the Archaea and appeared to be restricted to extreme halophilic environments. Our understanding of the abundance and diversity of this family has been radically transformed by findings over the past three years. Genome sequencing of cultivated microbes as well as environmental genomics have unexpectedly revealed archaeal rhodopsin homologs in the other two domains of life as well, namely Bacteria and Eucarya. Organisms containing these homologs inhabit such diverse environments as salt flats, soil, freshwater, and surface and deep ocean waters, and they comprise a broad phylogenetic range of microbial life, including haloarchaea, proteobacteria, cyanobacteria, fungi, and algae. Analysis of the new microbial rhodopsins and their expression and structural and functional characterization reveal that they fulfill both ion transport and sensory functions in various organisms, and use a variety of signaling mechanisms. We have obtained the first crystallographic structure for a photosensory member of this family, the phototaxis receptor sensory rhodopsin II (SRII, also known as phoborhodopsin) that mediates blue-light avoidance by the haloarchaeon Natronobacterium pharaonis. The structure obtained from x-ray diffraction of 3D crystals prepared in a cubic lipid phase reveals key features responsible for its spectral tuning and its sensory function. The mechanism of SRII signaling fits a unified model for transport and signaling in this widespread family of phototransducers.

• Microbiology and Biotechnology Letters
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• v.46 no.4
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• pp.313-319
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• 2018

Halophilic lactic acid bacteria (LAB) were isolated from myeolchi-jeotgal (23% NaCl, w/v) fermented in jangdok (Korean earthenware) located outside a house. They were identified as Tetragenococcus halophilus by 16S rRNA and recA gene sequencing. Four T. halophilus isolates showing high protease activities were selected for further studies. Four strains grew well, reaching $OD_{600}$ values of 0.75-0.92 at 18% NaCl content (w/v) and 0.28-0.44 at 23% salt. They showed rapid growth, attaining $OD_{600}$ values of 1.1-1.2 at $20-30^{\circ}C$, but did not grow at $4^{\circ}C$. At $15^{\circ}C$, the highest $OD_{600}$ values, which exceeded 0.6, were observed at 20 days, and were higher than those of cultures at $37^{\circ}C$ and $42^{\circ}C$ (approximately 0.5). Four isolates grew best in broth where the initial pH was adjusted to 8 and did not grow at $pH{\leq}4$. T. halophilus BS2-36 showed the highest survival ratio of 18.7% after 2 hours of exposure at pH 3. BS2-36 showed the highest survival ratio (1.29%) in presence of 0.3% bile salts. T. halophilus BS2-36 seems a promising candidate as a starter for jeotgal and other fermented foods with high salinities.

• Journal of Species Research
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• v.8 no.2
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• pp.197-214
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• 2019

The taxonomic hierarchy of the phylum Proteobacteria was assessed, after which the isolation and classification state of Proteobacteria species with valid names for Korean indigenous isolates were studied. The hierarchical taxonomic system of the phylum Proteobacteria began in 1809 when the genus Polyangium was first reported and has been generally adopted from 2001 based on the road map of Bergey's Manual of Systematic Bacteriology. Until February 2018, the phylum Proteobacteria consisted of eight classes, 44 orders, 120 families, and more than 1,000 genera. Proteobacteria species isolated from various environments in Korea have been reported since 1999, and 644 species have been approved as of February 2018. In this study, all novel Proteobacteria species from Korean environments were affiliated with four classes, 25 orders, 65 families, and 261 genera. A total of 304 species belonged to the class Alphaproteobacteria, 257 species to the class Gammaproteobacteria, 82 species to the class Betaproteobacteria, and one species to the class Epsilonproteobacteria. The predominant orders were Rhodobacterales, Sphingomonadales, Burkholderiales, Lysobacterales and Alteromonadales. The most diverse and greatest number of novel Proteobacteria species were isolated from marine environments. Proteobacteria species were isolated from the whole territory of Korea, with especially large numbers from the regions of Chungnam/Daejeon, Gyeonggi/Seoul/Incheon, and Jeonnam/Gwangju. Most Halomonadaceae species isolated from Korean fermented foods and solar salterns were halophilic or halotolerant. Air-borne members of the genera Microvirga, Methylobacterium, and Massilia had common characteristics in terms of G+C content, major respiratory quinones, and major polar lipids.

• The Korean Journal of Mycology
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• v.48 no.4
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• pp.457-473
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• 2020

We investigated the distribution and diversity of fungi in brackish water and soil from the Eulsukdo Island, Geumgang Estuary Bank, Suncheon Bay, Dae-ho Tide Embankment and coastal sand dune in Sinduri and Bu-nam Tide Embankment, Korea. Fungi were isolated from water samples by hand-pumped filtration, and soil samples were collected and diluted. The isolated fungi were incubated in potato dextrose agar at 25℃. A total of 173 fungal strains were isolated from brackish water and identified according to their respective internal transcribed spacer via phylogenetic analysis. The diversity of all fungal strains was analyzed according to diversity indices. The fungal strains belonged to any of 18 taxonomic orders: Pleosporales, Eurotiales, Capnodiales, Hypocreales, Polyporales, Saccharomycetales, Agaricales, Glomerellales, Mucorales, Dothideales, Russulales, Xylariales, Sordariales, Myrmecridiales, Tubeufiales, Onygenales, Cantharellales, and Amphisphaeriales. Cladosporium spp. (20%), Penicillium spp. (19%), and Fusarium sp. (5%) comprised majority of the identified strains. Two species from the fungal isolates were newly identified in Korea: Sarocladium kiliense NNIBRFG3280 and Fusicolla merismoides NNIBRFG23708.

• Journal of Microbiology and Biotechnology
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• v.32 no.11
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• pp.1427-1434
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• 2022

Two novel, halotolerant strains of Martelella soudanensis, NC18^T and NC20, were isolated from deep subsurface sediment, deeply sequenced, and comparatively analyzed with related strains. Based on a phylogenetic analysis using 16S rRNA gene sequences, the two strains grouped with members of the genus Martelella. Here, we sequenced the complete genomes of NC18^T and NC20 to understand the mechanisms of their halotolerance. The genome sizes and G+C content of the strains were 6.1 Mb and 61.8 mol%, respectively. Moreover, NC18^T and NC20 were predicted to contain 5,849 and 5,830 genes, and 5,502 and 5,585 protein-coding genes, respectively. Both strains contain the identically predicted 6 rRNAs and 48 tRNAs. The harboring of halotolerant-associated genes revealed that strains NC18^T and NC20 might tolerate high salinity through the accumulation of potassium ions in a "salt-in" strategy induced by K⁺ uptake protein (kup) and the K⁺ transport system (trkAH and kdpFABC). These two strains also use the ectoine transport system (dctPQM), the glycine betaine transport system (proVWX), and glycine betaine uptake protein (opu) to accumulate "compatible solutes," such as ectoine and glycine betaine, to protect cells from salt stress. This study reveals the halotolerance mechanism of strains NC18^T and NC20 in high salt environments and suggests potential applications for these halotolerant and halophilic strains in environmental biotechnology.