• Journal of Microbiology and Biotechnology
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• v.28 no.1
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• pp.12-21
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• 2018

Photorhabdus temperata (PT), a gram-negative bacterium, lives symbiotically within entomopathogenic nematodes. The insecticidal compounds derived from Photorhabdus are used as biopesticides in agriculture. However, the physiological properties are not well characterized. In the course of our screening for neuroprotective and anti-neuroinflammatory substances from natural products, the culture broth of PT showed considerable activities. By activity-guided purification, five anthraquinones, namely, 3-methoxychrysazine (1), 1,3-dimethoxy-8-hydroxy-9,10-anthraquinone (2), 1,3,8-trihydroxy-9,10-anthraquinone (3), 3,8-dihydroxy-1-methoxy-9,10-anthraquinone (4), and 1,3,4-trimethoxy-8-hydroxy-9,10-anthraquinone (5), were isolated from the ethyl acetate fraction of the PT culture broth. Among the isolated compounds, $75{\mu}M$ 3 significantly protected mouse hippocampal neuronal cells (HT22) against 5 mM glutamate-induced cell death via the inhibition of reactive oxygen species production, $Ca^{2+}$ influx, and lipid peroxidation. Additionally, 3 and 4 effectively suppressed the interferon-${\gamma}$-induced neuroinflammation of mouse-derived microglial cells (BV2) at 10 ng/ml, via the reduction of nitric oxide, interleukin-6, and tumor necrosis factor-${\alpha}$. Anthraquinones 3 and 4 derived from the PT culture broth are a potential starting point to discover neuroprotective and anti-neuroinflammatory drug leads. The novel compound 5 is reported for the first time in this study.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.1001-1005
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• 2010

The chitinase-producing strain TKU008 was isolated from soil in Taiwan, and it was identified as a new species of Pseudomonas. The culture condition suitable for production of chitinase was found to be shaking at $30^{\circ}C$ for 4 days in 100 ml of medium containing 1% shrimp and crab shell powder, 0.1% $K_2HPO_4$, and 0.05% $MgSO_4{\cdot}7H_2O$ (pH 7). The TKU008 chitinase was suppressed by the simultaneously existing protease, which also showed the maximum activity at the fourth day of incubation. The molecular mass of the chitinase was estimated to be 40 kDa by SDS-PAGE. The optimum pH, optimum temperature, pH stability, and thermal stability of the chitinase were pH 7, $50^{\circ}C$, pH 6-7, and <$50^{\circ}C$, respectively. The chitinase was completely inhibited by $Mn^{2+}$ and $Cu^{2+}$. The results of peptide mass mapping showed that 11 tryptic peptides of the chitinase were identical to the chitinase CW from Bacillus cereus (GenBank Accession No. gi 45827175) with a 32% sequence coverage.

• Journal of the Korean Wood Science and Technology
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• v.35 no.4
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• pp.61-66
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• 2007

The study was performed to purify and characterize laccase in culture of Trametes versicolor. The fungus was grown in liquid culture media of PDB and added 2,5-xylidine (0.2 mM) after 5 days to enhance the production of laccase. The fungal culture was incubated at $25^{\circ}C$ on a rotary shaker (120 rpm) for 7days, and the culture broth was clarified through Glass filter (GF/C). The aqueous solution was concentrated by ultramicrofiltration (Viva flow 50, GE Healthcare Bioscience, USA) and loaded onto a Hitrap Q FF column. Laccase activity could be detected at one peak, and this enzyme has a molecular mass of approximately 53kDa as determined by SDS-PAGE The optimum pH and temperature for syringaldazine were 5.0 and $60^{\circ}C$, respectively. The specific activity of crude, concentrated and purified laccase were 32, 409, and 1,243 U/mg, respectively.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2005.06a
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• pp.245-247
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• 2005

A cellulolytic fungus isolated from Agave plantation in northeastern Thailand was identified as Acrophialophora nainiana. The fungus was capable of growing at pH between 3 - 7 and 25 - 45 $^{\circ}C$, with the optimum conditions at pH 5.0 and 40 $^{\circ}C$. The wild isolate produced cellulases, comprising of exoglucanase (0.019 U/mg protein), endoglucanase (0.366 U/mg protein), and ${\beta}$-glucosidase (0.001 U/mg protein). Mutations with UV and NTG produced the UV 10-2 mutant with cellulases activities including exoglucanase (0.093 U/mg protein), endoglucanase (0.585 U/mg protein), and ${\beta}$-glucosidase (0.013 U/mg protein). Purification of the enzymes with ultrafiltration, ammonium sulfate precipitation, and ion-exchange chromatography yielded the maximal cellulase specific activities of 2.736 U/mg protein (exoglucanase), 0.235 U/mg protein (endoglucanase), and 0.008 U/mg protein (${\beta}$-glucosidase). The mutant's cellulases were the most active at pH 5.0 and 60 $^{\circ}C$. Ion-exchange chromatography revealed that A. nainiana UV 10-2 cellulases were comprised of two peaks with one peak showing the single endoglucanase activity while the other peak showed a mixture of the three enzyme activities. Production of A. nainiana UV 10-2 cellulases using banana leaf stalk as the sole carbon source gave comparable yields to that of the pure ${\alpha}$-cellulose. The enzymes were used in the simultaneous saccharification and fermentation (SSF) of plant residue (Coix aquatica) along with Kluveromyces marxianus to produce ethanol. Moreover, when the enzymes were used in the bioscouring process of fabric, the desiravle traits of textile processing including immediate water absorbency, increased in whiteness and reduction of yellowness of the treated fabric were observed.

• Journal of Microbiology
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• v.44 no.3
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• pp.293-300
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• 2006

The Escherichia coli heat-labile enterotoxin B subunit (HLT-B) is one of the most powerful mucosal immunogens and known mucosal adjuvants. However, the induction of high levels of HLT-B expression in E. coli has proven a difficult proposition. Therefore, in this study, the HLT-B gene was cloned from pathogenic E. coli and expressed as a fusion protein with GST (glutathion S-transferase) in E. coli BL2l (DE3), in an attempt to harvest a large quantity of soluble HLT-B. The culture conditions, including the culture media used, temperature, pH and the presence of lactose as an inducer, were all optimized in order to obtain an increase in the expression of soluble GST-rHLT-B. The biological activity of the purified rHLT-B was assayed in a series of GMI-ELISA experiments. The findings of these trials indicated that the yield of soluble recombinant GST-rHLT-B could be increased by up to 3-fold, as compared with that seen prior to the optimization, and that lactose was a more efficient alternative inducer than IPTG. The production of rHLT-B, at 92 % purity, reached an optimal level of 96 mg/l in a 3.7 L fermentor. The specific GM1 binding ability of the purified rHLT-B was determined to be almost identical to that of standard CTB.

• KSBB Journal
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• v.26 no.2
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• pp.100-106
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• 2011

Strain BCNU 5011 was isolated from forest soil samples collected in the Taebaek mountain in the Gangwon province, Korea. The biochemical, physiological and 16S rRNA sequence analysis strongly indicated that this isolate was most closely related to Paenibacillus polymyxa. A maximum production level of antimicrobial substances of Paenibacillus sp. BCNU 5011 was achieved under aerobic incubation at $30^{\circ}C$ for 3 days in SST broth.Paenibacillus sp. BCNU 5011 showed a broad spectrum of activity against Gram positive and Gram negative bacteria, including methicllinresistant Staphylococcus aureus (MRSA). Paenibacillus sp. BCNU 5011 was also shown to inhibit the growth of different potential human pathogenic bacteria and fungi in vitro. Peptide extract showed better antimicrobial activity than solvent extracts. But active antimicrobial compounds might be included in both peptide extract and solvent extracts. Further separation, purification and identification of active principles leads project to develop antimicrobial agents and anti-MRSA agents.

• Microbiology and Biotechnology Letters
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• v.50 no.4
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• pp.508-511
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• 2022

In this study, Phaseolus vulgaris (kidney bean) leghemoglobin a (PhLba) gene was cloned into pPICZαA and expressed in Pichia pastoris to sustainably produce a heme-carrying protein for organoleptic use in plant-based meat. The recombinant PhLba protein was secreted into the culture medium in a solubilized form, and the molecular weight of the purified PhLba was estimated to be 16.5 kDa using SDS-PAGE. In addtion, the yield of recombinant PhLba holoprotein was enhanced by supplementation of the cultivation medium with hemin. This result indicates that the apo-forms of PhLba can be effectively saturated with cofactor.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.299-299
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• 2022

Whole wheat is rich in dietary fiber and contains various biological activity substances such as arabinoxylan, phytic acid and phenolic compounds. However, excessive fiber contents of whole wheat has a negative effect on dough formation, making it difficult to process. In this study, we tried to improve the usability of whole wheat by suggesting an appropriate degree of purification of whole wheat from 'Saekeumkang', a domestic wheat cultivar containing protein and gluten suitable for noodle production. The contents of arabinoxylan, phytic acid, and vitamin E were measured in the polishing rate range of 5-20% of whole wheat flour. As the milling ratio increased, the flour properties improved. The arabinoxylan and phytic acid content of whole wheat were 67.95 mg/g and 0.87 mg/g, but when milled at 20%, arabinoxylan and phytic acid were 60% and 80% of whole wheat, respectively. And as the milling ratio increased, the vitamin E content tended to decrease (whole wheat: 4.063 mg/100 g, 20% milled: 2.96 mg/100 g), However, the vitamin E composition ratio did not change. On the other hand, α-tocopherol showed the greatest than other vitamin E isomers. Therefore, further studies needed to optimize milling rate to improve the final product while maintaining the approximate nutritional and functional value of the whole wheat.

• Advances in nano research
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• v.15 no.5
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• pp.441-449
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• 2023

Heavy metals, widely present in the environment, have become significant pollutants due to their excessive use in industries and technology. Their non-degradable nature poses a persistent environmental problem, leading to potential acute or chronic poisoning from prolonged exposure. Recent research has focused on separating heavy metals, particularly from industrial and mining sources. Industries such as metal plating, mining operations, tanning, wood and chipboard production, industrial paint and textile manufacturing, as well as oil refining, are major contributors of heavy metals in water sources. Therefore, removing heavy metals from water is crucial, especially for safe water supply in swimming and water sports. Iron oxide nanoparticles have proven to be highly effective adsorbents for water contaminants, and efforts have been made to enhance their efficiency and absorption capabilities through surface modifications. Nanoparticles synthesized using plant extracts can effectively bind with heavy metal ions by modifying the nanoparticle surface with plant components, thereby increasing the efficiency of heavy metal removal. This study focuses on removing lead from industrial wastewater using environmentally friendly, cost-effective iron nanoparticles synthesized with Genovese basil extract. The synthesis of nanoparticles is confirmed through analysis using Transmission Electron Microscope (TEM) and X-ray diffraction, validating their spherical shape and nanometer-scale dimensions. The method used in this study has a low detection limit of 0.031 ppm for measuring lead concentration, making it suitable for ensuring water safety in swimming and water sports.

• Journal of the Korean Applied Science and Technology
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• v.33 no.3
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• pp.498-506
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• 2016

1, 2-Hexanediol galactoside (HD-gal) has been previously synthesized from 1, 2-hexanediol (HD), in which recombinant ${\beta}$-galactosidase (${\beta}$-gal) of Escherichia coli (E. coli) was used for transgalactosylation reaction. In this study, a method for HD-gal purification from the reaction mixture was particularly investigated. Using ${\beta}$-gal-containing E. coli, HD-gal was synthesized from 75 mM HD for 48 hr under 300 g/l lactose concentration. Then, HD-gal synthesis from HD was confirmed by TLC analysis, and the existence of E. coli ${\beta}$-gal during 48 hr-reaction was also confirmed by Western blotting, in which the conversion yield of HD to HD-gal reached about 94% during 48 hr. To establish an efficient method for HD-gal purification, we carried out the solvent extraction of the reaction mixture, followed by silica gel chromatography, particularly in order to remove the residual HD. Two water-immiscible solvents, such as methylene chloride and ethyl acetate, were investigated comparatively to find out appropriate solvent. Then, it was found that residual HD was almost removed when ethyl acetate extraction of water phase of reaction mixture was carried out four times. Subsequently, silica gel chromatography was carried out, and purified HD-gal could be finally obtained. The production yield for HD-gal from 75 mM HD was $8.9{\pm}0.6%$ (n=3) (mole basis) or $21.1{\pm}1.4%$ (n=3) (weight basis). For further study, using purified HD-gal, we will investigate the minimum inhibitory concentrations (MICs) of HD-gal against bacteria. In addition, cytotoxicity to human skin cells of HD-gal will be examined.