• KSBB Journal
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• v.28 no.6
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• pp.356-365
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• 2013

The novel Aloe gels were prepared with dewatering and impregnation by soaking (DIS) processing of Aloe vera leaf slice at four different temperatures (25, 35, 45 and $55^{\circ}C$), using dehydration solution of 40% (w/v) polyethylene glycol (PEG4000). The PEG-impregnation to Aloe vera leaf slice during DIS was observed depending on immersion temperature, and the PEG-impregnated Aloe vera gel (PEG-i-AVG) obtained was characterized using $^1H$ NMR, FT-IR, GPC, XRD and TGA. The PEG-i-AVG had the higher levels of Aloe bioactives (glucomannan and O-acetyl contents) and better quality indices by $^1H$ NMR and FT-IR spectroscopy than those of native Aloe gel. Also, the obtained Aloe gel maintained the bimodal patterns in higher molecular weight region by GPC indicating no degradation of polysaccharide from native Aloe gel. The result observed by SEM confirmed a surface modification by forming the porous structure, and TGA result exhibited better thermal stability than that of native Aloe gel. XRD result revealed that the crystalline structure in Aloe gel was led by incorporation of PEG. Significant decrease of %insolubility and high enhancement of water solubility index were observed, respectively, and highly ordered conformation such as a helix structure was also indicated by Congo red reaction. We concluded that the modification effect for enhancing function of native Aloe gel was successfully obtained by DIS process using PEG as a dehydrating agent. These results suggested that this DIS process had a high potential for developing a new minimally processed product from Aloe vera leaf.

• Journal of Microbiology and Biotechnology
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• v.28 no.8
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• pp.1282-1292
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• 2018

The exopolysaccharide (EPS) produced by Bacillus amyloliquefaciens GSBa-1 was isolated and purified by ethanol precipitation, and DEAE-cellulose and Sepharose CL-6B chromatographies. The molecular mass of the purified EPS was determined to be 54 kDa. Monosaccharide analysis showed that the EPS was composed of predominantly glucose, and it was further confirmed by NMR spectroscopy to be ${\alpha}-glucan$ that consisted of a trisaccharide repeating unit with possible presence of two ${\alpha}-(1{\rightarrow}3)$ and one ${\alpha}-(1{\rightarrow}6)$ glucosidic linkages. Microstructural analysis showed that the EPS appeared as ellipsoid or globose with a smooth surface. The EPS had a degradation temperature at $240^{\circ}C$. Furthermore, the EPS had strong DPPH and hydroxyl radical scavenging activities, and moderate superoxidant anion scavenging and metal ion-chelating activities. This is the first characterization of a glucan produced by B. amyloliquefaciens with strong antioxidant activity. The results of this study suggest the potential of the EPS from B. amyloliquefaciens GSBa-1 to serve as a natural antioxidant for application in functional products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.105-113
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• 1995

Procedures for isolatin of chitin have been developed from crab(Chionoecetes opilio) shell waste with 26. 65% chitin on a dry basis. Optimal conditions for demineralization of crab shell were 1N HCl at ambient temperature for 30min with a solids to solbent ratio of 1 : 15(w/v). Optimal deproteinization involved treatment with 5% NaOH at $65^{\circ}C$ for 1 hr with a solids to solvent ratio of 1 : 15(w/v). Effective decoloration was achieved by bleaching with 0.32% sodium hypochlorite solution for 3min with a solids to solvent ratio of 1 : 10(w/v). Particular attentin was given to characterization of the physicochemical properties of the crab chitin. Chitins, from four different mesh sizes of crab shell, did not show significant differences in nitrogen and ash compositions. Bleaching decreased the viscosity of chitin but did not affect its solubility.

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.181-191
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• 2021

The present study addresses isolation, optimization, partial purification, and characterization of a haloalkaline serine protease from a newly isolated haloarchaeal strain isolated from Wadi El Natrun in Egypt. We expected that a two-step sequential statistical approach (one variable at a time, followed by response surface methodology) might maximize the production of the haloalkaline serine protease. The enzyme was partially purified using Hiprep 16/60 sephacryl S-100 HR gel filtration column. Molecular identification revealed the newly isolated haloarchaeon to be Natrialba hulunbeirensis strain WNHS14. Among several tested physicochemical determinants, casamino acids, KCl, and NaCl showed the most significant effects on enzyme production as determined from results of the One-Variable-At-A-time (OVAT) study. The BoxBehnken design localized the optimal levels of the three key determinants; casamino acids, KCl, and NaCl to be 0.5% (w/v), 0.02% (w/v), and 15% (w/v), respectively, obtaining 62.9 U/ml as the maximal amount of protease produced after treatment at 40℃, and pH 9 for 9 days with 6-fold enhancement in yield. The enzyme was partially purified after size exclusion chromatography with specific activity, purification fold, and yield of 1282.63 U/mg, 8.9, and 23%, respectively. The enzyme showed its maximal activity at pH, temperature, and NaCl concentration optima of 10, 75℃, and 2 M, respectively. Phenylmethylsulfonyl fluoride (PMSF, 5 mM) completely inhibited enzyme activity.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.E
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• pp.29-38
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• 2000

For the detailed characterization of atmospheric aerosol, the analysis of single particle is highly valuable. In this study, to investigate the characteristics of single Asian dust storm particles, scanning electron microscope(SEM) coupled with and energy dispersive X-ray microanalyzer(EDX) and micro-PIXE were applied. Sampling was performed at Kyoto University located in Kyoto, Japan, in spring of 1999. Mass concentration during Asian dust storm events was higher roughly 3∼5 times than measured in the season of the highest concentration. Single particles were generally sharp-edged and irregular in shape and contained mostly crustal elements. Significant amount of S in coarse fraction was detected in individual particles. A large particles in coarse fraction existed as the mixture of soil components and S. A good agreement between the result of SEM-EDX analysis and that iof micro-PIXE analysis was obtained in this study.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3225-3232
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• 2012

The purposes of this research were to synthesize amoxicillin-carrying magnetic nanoparticles. Magnetic nanoparticles were prepared by a chemical precipitation of ferric and ferrous chloride salts in the presence of a strong basic solution. PLGA and PLGA-PEG copolymers were prepared by ring opening polymerization of lactide (LA) and glycolide (GA) (mole ratio of LA: GA 3:1) with or without polyethylene glycol (PEG). Amoxicillin loaded magnetic PLGA and PLGA-PEG nanoparticles were prepared by an emulsion-evaporation process (o/w). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) photomicrographs showed that the magnetic nanoparticles have the mean diameter within the range of 65-260 nm also they were almost spherical in shape. Magnetic nanoparticles prepared with PLGA showed more efficient entrapment (90%) as compared with PLGA-PEG (48-52%) nanoparticles. In-vitro release of amoxicillin from magnetic PLGA nanoparticles showed that 78% of drug was released over 24 hours. The amount of amoxicillin released from PLGA-PEG s was higher than PLGA.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.360.2-360.2
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• 2016

CuSn thin films were fabricated by rf magnetron co-sputtering method on the Si(100) substrate for evaluation of the antibacterial effect. The co-sputtering process was performed with different rf powers and sputtering times to regulate the thickness of the films and relative atomic ratio of Cu to Sn. The physicochemical properties of the CuSn thin films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray induced Auger electron spectroscopy (XAES), Optical microscope (OM), 4-point probe, and antibacterial test. An antibacterial test was conducted with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as changing contact times between CuSn fillms and bacteria suspension. We compared to the crystalline structures of films before sterilization and after sterilization by XRD measurement. The changes of oxidation states of Cu and Sn and the chemical environment of films before and after antibacterial test were investigated with high resolution XPS spectra in the regions of Cu 2p, Cu LMM, and Sn 3d. After antibacterial test, the morphology of the films was checked with an OM images. The electrical properties of the CuSn films such as surface resistance and conductivity were measured by using 4-point probe.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.1
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• pp.1-6
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• 2004

The human chemokine, the short version of leukotactin-1(shLkn-1;molecular weight=7.2 kD and 66 amino acids), was expressed and secreted into a culture medium using the me-thylotrophic yeast, Pichia pastoris. The recombinant shLkn-1 was purified from the culture supernatant using a simple two-step procedure consisting of cation exchange and reverse phase chromatography(RPC), in which shLkn-1 was highly purified (99.5%) with a high recovery yield of 82.7%. The C-terminal truncated derivative of shLkn-1 was found in the supernatant and was separated by RPC. The physicochemical properties of the purified shLkn-1 were verified to be the same as expected. The biological activity of the purified recombinant shLkn-1 was also quantified using a chemotaxis assay. It was observed that the recombinant shLkn-1 had the maximum migration activity at a concentration of 10nM, as potent as MIP-1${\alpha}$.

• KSBB Journal
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• v.26 no.3
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• pp.217-222
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• 2011

Itraconazole is a triazole antifungal agent to inhibit most fungal pathogens. To improve the oral absorption and dissolution of poorly water-soluble itraconazole, microsponge system composed of $Eudragit^{(R)}$ E100 and polyvinyl alcohol(PVA) formulated by quasi-emulsion solvent diffusion method, and its physicochemical properties and pharmacokinetic parameters of itraconazole were studied. The microsponge of itraconazole were discrete free flowing micro sized particles with perforated orange peel like morphology as visualized by scanning electron microscope (SEM). Results showed that the drug loading efficiency, production yield, and particle size of itraconazole microsponge were affected by drug to polymer ratio, the volume of internal phase containing methylene chloride, stirring rate and the concentration of PVA used. Also, the results showed that the dissolution rate of itraconazole from the microsponges was affected by drug to polymer ratio. In other words, the release rate of itraconazole from microsponges was increased from at least 27.43% to 64.72% after 2 h. The kinetics of dissolution mechanism showed that the dissolution data followed Korsmeyer-Peppas model. Therefore, these results suggest that microsponge system can be useful for the oral delivery of itraconazole by manipulating the release profile.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.2
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• pp.151-155
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• 2003

Using gel filtration chromatography, high molecular silk fibroin with high purity was obtained and silk flbroin microsphere particles (SFMP) could be simply made by spray dryer method. Also, some of the physicochemical properties of SFMP and morphology were investigated. The average molecular weight of pure silk fibroin protein dissolved in calcium chloride is about 61,500g/㏖ as measured by gel permeation chromatography. SFMP was spherical in shape, and particles, sized average of 2 ${\pm}$ 10 ${\mu}$, were observed by SEM and particle analyzer, respectively. Obtaining microspheres particles by spray dryer method accelerated the transition from the random coil to the $\beta$-sheet structure during spray dryer treatment. It was identified by the basic fourier transform infrared spectroscopy of SFMP. The swelling ratio of SFMP is majorly dependent on the pH of the solution, not on the occurred gelation. The characteristic structure, which might be applicable to immobilization of drugs is superior to other matrix materials for the use of biomaterials with skin affinity.