• Journal of the Korean Wood Science and Technology
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• v.36 no.5
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• pp.56-65
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• 2008

In this paper experimental results are presented for the rheological behavior of high-solids saccharification of mixed northeast hardwood as a model feedstock. The experimental determination of the viscosity, shear stress, and shear rate relationships of the 10 to 20 percent slurry concentrations with constant enzyme concentrations were performed under variable rotational speed of a viscometer (2.0 to 200 RPM) at combined temperatures (50 to $30^{\circ}C$) for the initial four hours. The viscosities of saccharification slurries observed were in the ranges of 0.024 to 0.028, 0.401 to 0.058, and 0.840 to 0.087 Pa s for shear rates up to 100 reciprocal seconds at 10, 15, and 20 percent initial solids (w/v) respectively. The fluid behavior of the suspensions was modeled using the power-law, the Herschel-Bulkley, the Casson, and the Bingham model. The results showed that broth slurries were pseudoplastic with a yield stress. The model slope increased and the model intercept decreased with increasing fermentation time at shear rates normal for the fermentor. The broth slurries exhibited Newtonian behavior at high and low shear rates during initial saccharification process. The solid particle size ranged from 57.8 to $70.0{\mu}m$ for $40^{\circ}C$ and from 44.0 to 57.5 11m for combined temperatures at 10, 15, and 20 percent initial solids (w/v) respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1301-1304
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• 2001

Deodorizing activity of polyphenol cxidase (PPO) extracted from apples was investigated by measuring the changes of methyl mercaptan as an indicator of halitosis in human mouths. In the studies of apple extracts on deodorizing activity, the deodorizing activity was increased with the amount of apple extracts. In the cases of adding PPO to the low molecular fraction of apple extracts, the deodorizing activities were increased with the amount of the law molecular fraction of apple extracts and the reaction time of the extracts with PPO. Deodorizing activities of PPO is thought that o-quinone as an intermidiate produced by an oxidative reaction of PPO during enzymatic browning reactions may react with methyl mercaptan to form a non-volatile and sulfur-containing compound .

• Journal of Powder Materials
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• v.14 no.4
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• pp.256-260
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• 2007

The surface of magnetite ($Fe_{3}O_{4}$) nanoparticles prepared by coprecipitation method was modified by carboxylic acid group of poly(3-thiophenacetic acid (3TA)) and meso-2,3-dimercaptosuccinic acid (DMSA). Then the lysozyme protein was immobilized on the carboxylic acid group of the modification of the magnetite nanoparticles. The magnetite nanoparticles are spherical and the particle size is approximately 10 nm. We measured quantitative dispersion state by dispersion stability analyzer for each $Fe_{3}O_{4}$ nanoparticles with and without surface modification. The concentration of lysozyme on the modified magnetite nanoparticles was also investigated by a UV-Vis spectrometer and compared to that of magnetite nanoparticles without surface modification. The functionalized magnetite particles had higher enzymatic capacity and dispersion stability than non-functionalized magnetite nanoparticles.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.280-281
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• 2007

본 논문에서는 생체 내에 삽입하거나 연속적으로 혈당을 모니터링하기 위하여 제작된 무효소 혈당세서의 바이오 패키징 및 특성 최적화에 관하여 고찰하였다. 3전극을 갖는 동일한 센서구조에서 sensitivity를 최대화하기 위해 평면형 백금전극을 사용한 센서, 메조포러스 구조가 작동전극에 형성된 센서, 메조포러스 구조가 작동전극과 보조전극에 형성된 무효소 혈당센서를 설계, 제작하고 비교하였다. 각각의 센서는 0.009${\mu}A$ $mM^{-1}cm^{-2}$, 5.46${\mu}A$ $mM^{-1}cm^{-2}$, 7.75${\mu}A$ $mM^{-1}cm^{-2}$의 sensitivity를 가졌다. 또한 생체 이식되었을 때 혈액 속에서 글루코스응답을 얻는 데에 있어 방해종인 Ascrobic Acid와 Acetaminophen의 반응을 최소화하고, 혈액 내의 단백질들이 전극에 엉겨 붙는 것을 막기 위해 생체 적합한 물질인 Nafion 을 패키징 멤브레인으로 적용하여 센서를 제작하였다. 이 센서는 0.36${\mu}A$ $mM^{-1}cm^{-2}$의 sensitivity를 가졌다.

• Journal of Microbiology and Biotechnology
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• v.29 no.6
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• pp.944-951
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• 2019

Lipases are industrial enzymes that catalyze both triglyceride hydrolysis and ester synthesis. The overexpression of lipase genes is considered one of the best approaches to increase the enzymatic production for industrial applications. Subfamily I.2. lipases require a chaperone or foldase in order to become a fully-activated enzyme. The goal of this research was to isolate, clone, and co-express genes that encode lipase and foldase from Burkholderia territorii GP3, a lipolytic bacterial isolate obtained from Mount Papandayan soil via growth on Soil Extract Rhodamine Agar. Genes that encode for lipase (lipBT) and foldase (lifBT) were successfully cloned from this isolate and co-expressed in the E. coli BL21 background. The highest expression was shown in E. coli BL21 (DE3) pLysS, using pET15b expression vector. LipBT was particulary unique as it showed highest activity with optimum temperature of $80^{\circ}C$ at pH 11.0. The optimum substrate for enzyme activity was $C_{10}$, which is highly stable in methanol solvent. The enzyme was strongly activated by $Ca^{2+}$, $Mg^{2+}$, and strongly inhibited by $Fe^{2+}$ and $Zn^{2+}$. In addition, the enzyme was stable and compatible in non-ionic surfactant, and was strongly incompatible in ionic surfactant.

• Korean Journal of Medicinal Crop Science
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• v.27 no.3
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• pp.186-193
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• 2019

Background: Astringent persimmon (Diospyros kaki Thunb. cv. Kojongsi) peels are by-products of dried persimmons. This study aimed to evaluate the antioxidant activities of Kojongsi persimmon peel (KPP) extracts prepared by 15 different extraction methods: 5 heating durations (0.5 - 2.5 h) at 3 heating temperatures (50, 70, and $90^{\circ}C$). Methods and Results: An increase in heating temperature increased the antioxidant effect of KPP extracts. Those prepared by heating at 1 h had the highest total phenol content, regardless of the heating temperature. In addition, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and cell-protective effects against $H_2O_2-induced$ oxidative stress were dependent on the total phenol contents of the extract. However, the KPP-induced increased in catalase expression was dependent on heating temperature and duration. Conclusions: These results suggest that extraction by heating at $90^{\circ}C$ for 1 h may enhance KPP's antioxidant effects, which mainly involve non-enzymatic antioxidant systems.

• Mass Spectrometry Letters
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• v.13 no.4
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• pp.139-145
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• 2022

Protein glycosylation is a common post-translational modification by non-template-based biosynthesis. In fungal biotechnology, which has great applications in pharmaceuticals and industries, the importance of research on fungal glycoproteins and glycans is accelerating. In particular, the importance of quantitative analysis of fungal glycans is emerging in research on the production of filamentous fungal proteins by genetic modification. Reliable mass spectrometry-based techniques for quantitative glycomics have evolved into chemical, enzymatic, and metabolic stable isotope labeling methods. In this study, we intend to expand quantitative glycomics by metabolic isotope labeling of glycans in Aspergillus niger, a filamentous fungus model, by the MILPIG method. We demonstrate that incubation of filamentous fungi in a culture medium with carbon-13 labeled glucose (1-¹³C₁) efficiently incorporates carbon-13 into N-linked glycans. In addition, for quantitative validation of this method, light and heavy glycans are mixed 1:1 to show the performance of quantitative analysis of various N-linked glycans simultaneously. We have successfully quantified fungal glycans by MILPIG and expect it to be widely applicable to glycan expression levels under various biological conditions in fungi.

• BMB Reports
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• v.57 no.7
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• pp.318-323
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• 2024

Regulation of cell fate and lung cell differentiation is associated with Aminoacyl-tRNA synthetases (ARS)-interacting multifunctional protein 2 (AIMP2), which acts as a non-enzymatic component required for the multi-tRNA synthetase complex. In response to DNA damage, a component of AIMP2 separates from the multi-tRNA synthetase complex, binds to p53, and prevents its degradation by MDM2, inducing apoptosis. Additionally, AIMP2 reduces proliferation in TGF-β and Wnt pathways, while enhancing apoptotic signaling induced by tumor necrosis factor-α. Given the crucial role of these pathways in tumorigenesis, AIMP2 is expected to function as a broad-spectrum tumor suppressor. The full-length AIMP2 transcript consists of four exons, with a small section of the pre-mRNA undergoing alternative splicing to produce a variant (AIMP2-DX2) lacking the second exon. AIMP2-DX2 binds to FBP, TRAF2, and p53 similarly to AIMP2, but competes with AIMP2 for binding to these target proteins, thereby impairing its tumor-suppressive activity. AIMP2-DX2 is specifically expressed in a diverse range of cancer cells, including breast cancer, liver cancer, bone cancer, and stomach cancer. There is growing interest in AIMP2-DX2 as a promising biomarker for prognosis and diagnosis, with AIMP2-DX2 inhibition attracting significant interest as a potentially effective therapeutic approach for the treatment of lung, ovarian, prostate, and nasopharyngeal cancers.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.4
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• pp.275-288
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• 1999

To understand the effects of ocean-dumping of organic wastes on bacteria, bacterial abundance and production, and hydrolytic activities of aminopeptidase (AMPase) and ${\beta}$-glucosidase (${\beta}$-GLCase) were measured 5 times in the euphotic zone of the dumping and non-dumping areas of the East Sea from April 1996 to September 1997. Comparing the depth-integrated values of phytoplankton biomass and bacterial parameters over the euphotic zone of dumping area with those of non-dumping area, we found that activities of ${\beta}$-GLCase in the oceanic dumping area were always higher than those in the oceanic non-dumping area. Also, thymidine-based bacterial production always correlated significantly with leucine-based bacterial production in dumping area (balanced growth), but not in non-dumping area (unbalanced growth). These results seem to be bacterial responses to continuous dumping of organic matter into the dumping area. Further, a relationship between bacterial abundance and production was significant in dumping area, but insignificant in non-dumping area, indicating that control mechanisms of bacterial abundance were different in two areas. Relationships between other bacterial parameters varied with areas and seasons, suggesting that bacteria might be regulated by different factors in spring and summer. Further studies are required to test whether these seasonal variabilities of regulating factor are associated with changes in temperature, temperature-related phenomena, or characteristics of wastes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.277-284
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• 2005

Micro-filtration (MF) or ultra-filtration (UF) system with hollow-fiber cartridge was introduced in order to improve the Quality level of commercial foxtail millet Yakju, which has an off-flavour and/or undesired colour after the thermal treatment. The filtration effects of cartridges such as MF (0.65, 0.45, 0.2, 0.1 $\mu$m) and UF (500 K dalton) were investigated. The physicochemical and sensory characteristics of the Yakju were then evaluated during the 6 months storage at room temperature. The exclusion ability of microorganism in samples was confirmed in all cartridges, but 0.45 pm MF-cartridge was suitable in the Yakju manufacture due to its superior filtration rate and efficiency. Changes in reducing sugar and colour difference of foxtail millet Yakju untreated or treated by heat ($65^{\circ}C$${\times}$10 min) were observed during the storage; after 6 months the L-value of thermal-treatment sample was decreased and its b-value, however, significantly increased so that its color became dark, in comparison to non-thermal treatment sample. This decrease of reducing sugar is assumed that color change is associated with non-enzymatic browning reaction. Sensory Quality of foxtail millet Yakju produced by non-thermal treatment was better than that of thermal treatment.