• Journal of Industrial Technology
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• v.39 no.1
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• pp.15-19
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• 2019

This work focused on characterization of the starch degradation activity from extremophile strain Deinococcus geothermalis. Glucoamylase gene from D. geothermalis was cloned and overexpressed by pET-21a vector using E. coli BL21 (DE3). In order to characterize starch degrading activity of recombinant glucoamylase, enzyme was purified using HisPur Ni-NTA column. The recombinant glucoamylase from D. geothermalis exhibited the optimum temperature as $45^{\circ}C$ for starch degradation activity. And highly acido-stable starch degrading activity was shown at pH 2. For further optimization of starch degrading activity with metal ion, various metal ions ($AgCl_2$, $HgCl_2$, $MnSO_4{\cdot}4H_2O$, $CoCl_2{\cdot}6H_2O$, $MgSO_4$, $ZnSO_4{\cdot}7H_2O$, $K_2SO_4$, $FeCl_2{\cdot}4H_2O$, NaCl, or $CuSO_4$) were added for enzyme reaction. As results, it was found that $FeCl_2{\cdot}4H_2O$ or $MnSO_4{\cdot}4H_2O$ addition resulted in 17% and 9% improved starch degrading activity, respectively. The recombinant glucoamylase from D. geothermalis might be used for simultaneous saccharification and fermentation (SSF) process at high acidic conditions.

• KSBB Journal
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• v.22 no.1
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• pp.1-6
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• 2007

The optimum liquid culture conditions were investigated for cell growth and polysaccharide production from liquid culture of Lentinus edodes. In flask culture, the optimal medium compositions for the polysaccharide production contained glucose 60 g/L, yeast extract 10 g/L, $KH_2PO_4$ 2.0 g/L, and $MgSO_4{\cdot}7H_2O$ 1.0 g/L. The maximum mycelial growth and polysaccharide production were 11.01 g/L and 1.64 g/L, respectively. In bioreactor, through the variation of aeration in order to increase mycelial growth and polysaccharide production, the maximum mycelial growth and polysaccharide production were 55.9 g/L at 8th day and 7.34 g/L at 7th day of cultivation with 1.5 vvm, respectively.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1134-1139
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• 1998

Quality changes of filter-sterilized Yakju were examined by filtration of Yakju through membranes followed by storing at $25^{\circ}C$ for 50 days. To evaluate quality changes of filter-sterilized Yakju, pH, titratable acidity, turbidity, and viable cell numbers of total bacteria, lactic acid bacteria, and yeast were measured. Titratable acidity, turbidity and viable cell numbers of non-sterilized Yakju increased, but pH profile decreased during the storage. In filter-sterilized Yakju, titratable acidity and turbidity did not change, while viable cells of total bacteria, lactic acid bacteria, and yeast were not detected during the storage. Addition of chitosan at the concentration of 0.1% (w/v) decreased the viable cell numbers significantly showing similar pH and titratable acidity profiles with non-sterilized Yakju.

• Journal of Biomedical Engineering Research
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• v.35 no.4
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• pp.81-86
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• 2014

One of the methods for Parkinson's disease(PD) tremor evaluation is the Clinical Tremor Rating Scale(CTRS). However, the method has some limitations that clinician ratings can vary because the scores are subjectively rated. In addition, most researches usually collected data measured on the more affected arm. In this study, we developed a portable wearable system(SNUMAP system) for measuring PD tremor. The SNUMAP system captures 3-dimensional motion using tri-accelerometer and tri-gyroscope on finger and wrist. 40 PD patients participated in resting tremor and postural tremor tasks, while wearing the system on both hands simultaneously. Estimated tremor scores from Leave-One-Out Cross Validation for regression were highly correlated to the average clinician CTRS scores for rest tremor($r^2$ = 0.87, RMSE = 0.48) and postural tremor($r^2$ = 0.82, RMSE = 0.48). Therefore, the quantitative assessment model can improve treatment of PD patients.

• Journal of Microbiology and Biotechnology
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• v.32 no.11
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• pp.1471-1478
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• 2022

2'-Fucosyllactose (2'-FL), the most abundant fucosylated oligosaccharide in human milk, has multiple beneficial effects on human health. However, its biosynthesis by metabolically engineered Escherichia coli is often hampered owing to the insolubility and instability of α-1,2-fucosyltransferase (the rate-limiting enzyme). In this study, we aimed to enhance 2'-FL production by increasing the expression of soluble α-1,2-fucosyltransferase from Helicobacter pylori (FucT2). Because structural information regarding FucT2 has not been unveiled, we decided to improve the expression of soluble FucT2 in E. coli via directed evolution using a protein solubility biosensor that links protein solubility to antimicrobial resistance. For such a system to be viable, the activity of kanamycin resistance protein (Kan^R) should be dependent on FucT2 solubility. Kan^R was fused to the C-terminus of mutant libraries of FucT2, which were generated using a combination of error-prone PCR and DNA shuffling. Notably, one round of the directed evolution process, which consisted of mutant library generation and selection based on kanamycin resistance, resulted in a significant increase in the expression level of soluble FucT2. As a result, a batch fermentation with the ΔL M15 pBCGW strain, expressing the FucT2 mutant (F#1-5) isolated from the first round of the directed evolution process, resulted in the production of 0.31 g/l 2'-FL with a yield of 0.22 g 2'-FL/g lactose, showing 1.72- and 1.51-fold increase in the titer and yield, respectively, compared to those of the control strain. The simple and powerful method developed in this study could be applied to enhance the solubility of other unstable enzymes.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.697-697
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• 2003

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.682-682
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• 2003

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.168-169
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• 2003

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.106-106
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• 2003