• Journal of Microbiology and Biotechnology
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• v.23 no.4
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• pp.473-482
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• 2013

The desulfurization ability of Sphingomonas subarctica T7b was evaluated using resting and immobilized cells with dibenzothiophene (DBT), alkyl DBTs, and commercial light gas oil (LGO) as the substrates. The resting cells of S. subarctica T7b degraded 239.2 mg of the initial 250 mg of DBT/l (1.36 mM) within 24 h at $27^{\circ}C$, while 127.5 mg of 2-hydroxybiphenyl (2-HBP)/l (0.75 mM) was formed, representing a 55% conversion of the DBT. The DBT desulfurization activity was significantly affected by the aqueous-to-oil phase ratio. In addition, the resting cells of S. subarctica T7b were able to desulfurize alkyl DBTs with long alkyl chains, although the desulfurization rate decreased with an increase in the total carbon number of the alkylated DBTs. LGO with a total sulfur content of 280 mg/l was desulfurized to 152 mg/l after 24 h of reaction. Cells immobilized by entrapment with polyvinyl alcohol (PVA) exhibited a high DBT desulfurization activity, including repeated use for more than 8 batch cycles without loss of biodesulfurization activity. The stability of the immobilized cells was better than that of the resting cells at different initial pHs, higher temperatures, and for DBT biodesulfurization in successive degradation cycles. The immobilized cells were also easily separated from the oil and water phases, giving this method great potential for oil biodesulfurization.

• Journal of the Korean institute of surface engineering
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• v.39 no.1
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• pp.25-34
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• 2006

Al-Mg alloy, an open rack vaporizer(ORV) material was reported to be corroded in seawater environments though the ORV material was coupled to thermally sprayed Al-Zn alloy functioning a sacrificial anode. In addition, the corrosion behavior based on the calculated corrosion potential did not match the observed corrosion behavior. Hence, the goal of this study is to get better understanding on Al or Al-Mg alloy coupled to Al-Zn alloy and to provide the calculated corrosion potential representing the corrosion behavior of the ORV material by immersion test, electrochemical tests, and calculation of corrosion and galvanic potential. The corrosion potentials of Al and Al alloys also depended on alloying element as well as surface defects. The corrosion potentials of Al and Al-Mg alloy were changed with time. In the meantime, the corrosion potentials of Al-Zn alloys were not. The corrosion rates of Al-Zn alloys were exponentially increased with zinc contents. The phenomena were explained with the stability of passive film proved by passive current density depending on pH and confirmed by the model proposed by McCafferty. Dissimilar material crevice corrosion (DMCC) test shows that higher content of zinc caused Al-Mg alloy corroded more rapidly, which was due to the fact that higher corrosion rate of Al-Zn makes [$H^+$] and [$Cl^-$] more concentrated within pit solution to corrode Al-Mg alloy. Considering electrochemical reactions within pit as well as bulk in the calculation gives better prediction on the corrosion behavior of Al and Al-Mg alloy as well as the capability of Al-Zn alloy for corrosion protection.

• Analytical Science and Technology
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• v.36 no.4
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• pp.180-190
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• 2023

The presence of process related impurities in any drug or the drug product was associated with its safety, stability and efficacy. The overall literature survey proved that there is no method published on the assessment of process related impurities in brigatinib. In this study, a simple, reliable and stable HPLC qualitative method was reported for quantification of process related impurities with easy and quick extraction procedure. The impurities along with standard brigatinib was resolved on Lichrospher^® C18 (250 mm × 4.6 mm; 5 ㎛ particle size) column in room temperature using methanol, acetonitrile, pH 4.5 phosphate buffer in 55:25:20 (v/v) at 1.0 mL/min as mobile phase and UV detection at 261 nm. The method produces well resolved peaks at retention time of 4.60 min, 12.28 min, 3.37 min, 7.34 min and 8.39 min respectively for brigatinib, impurity A, B, C and D. The method produces a very sensitive detection limit of 0.0065 ㎍/mL, 0.0068 ㎍/mL, 0.0053 ㎍/mL and 0.0058 ㎍/mL for impurity A, B, C and D respectively with calibration curve linear in the concentration range of 22.5-135 ㎍/mL for brigatinib and 0.0225-0.135 ㎍/mL for impurities. The method produces all the validation parameters under the acceptable level and doesn't produces any considerable changes in peak area response while minor changes in the developed method conditions. The method can effectively resolve the unknown stress degradation products along with known impurities with less % degradation. The method can efficiently resolve and quantify the impurities in formulation and hence can suitable for the routine quality analysis of brigatinib in raw material and formulation.

• Journal of the Korean Wood Science and Technology
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• v.51 no.6
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• pp.542-554
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• 2023

This study is a continuation of our previous work, which focused on the resistance of jabon wood to termites after impregnation with wood vinegar (WV) and animal-based adhesive (kak). This paper presents the physicomechanical properties of fast-growing jabon wood impregnated with kak at two concentrations (8% and 10%) in wood vinegar or water as a solvent with and without 4% borax. The physical properties of the impregnation solution, that is, viscosity, density, pH, and solid content, were evaluated according to SNI 06-4567-1998. Some physical parameters, such as weight percent gain (WPG), density, water uptake, anti-swelling efficiency (ASE), crystallinity, and mechanical properties, i.e., modulus of elasticity (MOE), modulus of rupture (MOR), and compression strength parallel to the grain (CS), of the impregnated wood were determined. Based on these results, wood impregnated using a mixture of kak in WV presented better physical (increased WPG, density, dimensional stability, and crystallinity) and mechanical (increased MOE/MOR and compression strength) properties than wood impregnated with a water solvent or untreated wood. The wood impregnated using WV and water solvent improved the physical and mechanical properties. The density of the wood increased by 44%-58% and 32%-47%, ASE radial-tangential increased by 38%-45%; 15%-28% after 24 h of water immersion, crystallinity increased by 59%-74%; 36%, MOE increased by 46%-57%; 28%-31%, MOR increased by 29%-34%; 14%-27%, and compression strength increased by 40%-76%; 38%-72% values to untreated wood.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.5
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• pp.729-737
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• 2018

Objective: Effect of addition of wheat bran (WB) and dried carrot pomace (DCP) on sensory, textural, colour, physico-chemical and nutritional characteristics of chicken sausage were evaluated. Methods: WB and DCP were used as a source of dietary fibre at 3%, 6%, and 9% level individually. Different quality attributes of sausages were estimated. One product from each source with very good sensory acceptability was selected to analyze dietary fibre content and shelf life under refrigerated storage. Results: Sensory acceptability of 3% fibre enriched sausage was comparable with control and a further increase in fibre level resulted in a decrease in sensory acceptability. Fibre enriched sausages were significantly harder and less cohesive than control sausage. Significant increase in gumminess and chewiness was observed at 6% level in WB treated sausages and 9% level in DCP treated sausages. Moisture content decreased significantly in all treated sausages, protein content decreased significantly in DCP-2 and DCP-3 sausages while fat content decreased in all WB and DCP-3 treated sausages in comparison to control. The fibre enriched sausage had significantly higher dietary fibre and lower cholesterol content. Cooking yield and emulsion stability increased in treated sausages and a significant difference was noticed at 6% level in both types of sausages. pH of WB treated sausages was significantly higher and DCP treated sausage significantly lower in comparison to control. Conclusion: The results of present study indicate that fibre enriched chicken sausage with moderate acceptability can be developed by incorporating WB and DCP each up to 9% level. Chicken sausage with very good acceptability, higher dietary fibre content and storability up to 15 days at refrigerated temperature can be developed by incorporating WB and DCP at 6% level each.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2671-2674
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• 2013

To elucidate the role of the evolutionarily conserved Tyr8 residue in rice Phi-class GSTF3, this amino acid was replaced with alanine and phenylalanine by site-directed mutagenesis, respectively. The replacement of Tyr8 with Ala significantly affected the catalytic activity and the kinetic parameters, whereas the substitutions of Tyr8 with Phe had almost no effect. The Y8A mutant resulted in approximately 90-100% decrease of the specific activity. Moreover, the Y8A mutant resulted approximately in 2-fold increase of $K_m$, approximately 60-80% decrease of $k_{cat}$, and approximately 6.5-fold decrease in $k_{cat}/K_m$. From the pH/log $k_{cat}/K_m$ plot, $pK_a$ values of the GSH in the wild-type enzyme-GSH complex, Y8A-GSH complex and Y8F-GSH complex were estimated to be approximately 6.8, 8.5 and 6.9, respectively. From these results, we suggest that the evolutionarily conserved Tyr8 residue in OsGSTF3 seems to influence the structural stability of the active site of OsGSTF3 rather than directly its catalytic activity.

• Microbiology and Biotechnology Letters
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• v.26 no.4
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• pp.290-296
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• 1998

Interspecific hybrids between Aspergillus oryzae var. oryzae and Penicillium chrysogenum (Tyr$\^$-/), high alkaline protease producing fungi, were obtained by nuclear transfer technique. Nuclei isolated from the wild type Aspergillus oryzae var. oryzae strain were transferred into auxotrophic Penicillium chrysogenum mutants and selected the new strains showing an increased protein degrading capability. Maximum production of protoplasts were obtained by 1% Novozym 234 at $30^{\circ}C$ for 3 hours and the most effective osmotic stabilizers for the isolation of protoplasts were 0.6M KCl. Frequencies of hybrid formation by nuclear transfer were 1.3${\times}$10$\^$-3/∼2.8${\times}$10$\^$-3/. They could be suggested as an aneuploid by the observation of genetic stability, conidial size, DNA content, and nuclear strain. The hybrids showed 1.1～2.2 fold higher alkaline pretense activities than parental strains.

• Korean Journal of Microbiology
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• v.33 no.1
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• pp.31-37
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• 1997

Intergeneric hybrids between Aspergillus niger and Perricillium ch~y.sop~um(Tyr ), hyperlipolytic enzyne-producing fungi, were obtained by nuclear transfer technique:. Optimal conditions for formation of intergeneric hybrids were investigated. Maximum production of protoplasts were obtainrd by 1% Novozym 234 at $30^{\circ}C$ for 3 hrs and the most effective osmotic stabilizers for the isolation of protoplasts were 0.6 M KC]. Frequencies of hybrid formation by nuclear transfer were $1.3{\times}$10^{-3}$$ $-3.8{\times}$10^{-3}$$. From the chervation of genetic stability, conidial size, DNA content, ;md nuclear stain, it was suggested that their karyotypes are aneuploid. The hybrids showed 1.4-2.2 fold higher lipase activities than parental strains. It was strongly supported by results of this study that nuclear transfer technique is much more efficient in the formation of intergeneric hybrids than protoplast fusion and is very useful for the improvement of strains.

• Journal of Microbiology and Biotechnology
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• v.25 no.7
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• pp.1007-1014
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• 2015

Plectasin, the first defensin extracted from a fungus (the saprophytic ascomycete Pseudoplectania nigrella), is attractive as a prospective antimicrobial agent. The purpose of this study was to establish a bacterium-based production system and evaluate the antimicrobial activity of the resulting plectasin. A gene encoding plectasin, with the codon preference of Escherichia coli, was optimized based on its amino acid sequence, synthesized using genesplicing with overlap extension PCR, and inserted into the expression vector pGEX-4T-1. The fusion protein was expressed in the soluble fraction of E. coli and purified using glutathione Stransferase affinity chromatography. Plectasin was cleaved from the fusion protein with thrombin and purified by ultrafiltration. The purified plectasin showed strong, concentrationdependent antimicrobial activity against gram-positive bacteria, including antibiotic-resistant bacteria, especially penicillin-resistant Enterococcus faecium. This antimicrobial activity was equal to chemically synthesized plectasin and was maintained over a wide range of pH and temperatures. This soluble recombinant expression system in E. coli is effective for producing plectasin at a relatively lower cost, and higher purity and efficiency than prior systems, and might provide a foundation for developing a large-scale production system. Overall, plectasin shows potential as a novel, high-performance, and safe antibiotic for the treatment of refractory diseases caused by drug-resistant bacterial strains.

• Journal of Microbiology and Biotechnology
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• v.19 no.2
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• pp.128-135
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• 2009

Acinetohacter baumannii BD5 was isolated from waters of Baek-du mountain, and the lipase gene was cloned using a PCR technique. The deduced amino acid sequence of the lipase and lipase chaperone were found to encode proteins of 325 aa and 344 aa with a molecular mass of 35 kDa and 37 kDa, respectively. The lipase gene was cloned and expressed in Escherichia coli BL21(trxB) as an inclusion body, which was subsequently solubilized by urea, and then purified using Ni-affinity chromatography. After being purified, the lipase was refolded by incubation at $4^{\circ}C$ in the presence of a 1:10 molar ratio of lipase:chaperone. The maximal activity of the refolded lipase was observed at a temperature of $35^{\circ}C$ and pH 8.3 when p-NP caprate(C10) was used as a substrate; however, 28% of the activity observed at $35^{\circ}C$ was still remaining at $0^{\circ}C$. The stability of the purified enzyme at low temperatures indicates that it is a cold-adapted enzyme. The refolded lipase was activated by $Ca^{2+},\;Mg^{2+},\;and\;Mn^{2+}$, whereas $Zn^{2+}\;and\;Cu^{2+}$ inhibited it. Additionally, 0.1% Tween 20 increased the lipase activity by 33%, but SDS and Triton X-100 inhibited the lipase activity by 40% and 70%, respectively.