• KSBB Journal
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• v.27 no.6
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• pp.352-360
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• 2012

Bacillus clausii I-52 which produced SDS- and $H_2O_2$-tolerant extracellular alkaline protease (BCAP) was isolated from heavily polluted tidal mud flat of West Sea in Incheon, Korea and stable strain (transformant C5) of B. clausii I-52 harboring another copy of BCAP gene in the chromosome was developed using the chromosome integration vector, pHPS9-fuBCAP. When investigated the production of BCAP using B. clausii transformant C5 through pilot-scale submerged fermentation (500 L) at $37^{\circ}C$ for 30 h with an aeration rate of 1 vvm and agitation rate of 250 rpm, protease yield of approximately 105,700 U/mL was achieved using an optimized medium (soybean meal 2%, wheat flour 1%, sodium citrate 0.5%, $K_2HPO_4$ 0.4%, $Na_2HPO_4$ 0.1%, NaCl 0.4%, $MgSO_4{\cdot}7H_2O$ 0.01%, $FeSO_4{\cdot}7H_2O$ 0.05%, liquid maltose 2.5%, $Na_2CO_3$ 0.6%). The enzyme stability of BCAP was increased by addition of polyols (10%, v/v) and also, the stabilities of BCAP towards not only the thermal-induced inactivation at $50^{\circ}C$ but also the SDS and $H_2O_2$-induced inactivation at $50^{\circ}C$ were enhanced. Among the polyols examined, the best result was obtained with propylene glycol (10%, v/v). The BCAP supplemented with propylene glycol exhibited extreme stability against not only the detergent components such as ${\alpha}$-orephin sulfonate (AOS) and zeolite but also the commercial detergent preparations. The granulized enzyme of BCAP was prepared with approximately 1,310,000 U/g of granule. Wash performance analysis using EMPA test fabrics revealed that BCAP granule exhibited high efficiency for removal of protein stains in the presence of anionic surfactants as well as bleaching agents. When compared to Savinase 6T$^{(R)}$ and Everlase 6T$^{(R)}$ manufactured by Novozymes, BCAP under this study probably showed similar or higher efficiency for the removal of protein stains. These results suggest that the alkaline protease produced from B. clausii transformant C5 showing high stability against detergents and high wash performance has significant potential and a promising candidate for use as a detergent additive.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.10
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• pp.685-690
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• 2014

The treatment of combined sewer overflow (CSO) is one of potential concerns in domestic wastewater treatment in Korea due to the pre-announce of CSO regulations. This work investigated the effects of disinfectant (NaOCl) concentration (0.11 to 4.0 mg $Cl_2/L$), pH (6.5 to 8.0), temperature (15 to $25^{\circ}C$), ammonia (10 to 41 mg N/L), and suspended solids (91 to 271 mg SS/L) on the chlorine disinfection of CSO. The effect of NaOCl concentration on the pseudo-$1^{st}$ order reaction rate for total coliform inactivation was described well with a saturation-type model with the half-velocity constant of 1.212 mg/L. The total coliform inactivation reaction rate decreased with SS and pH, and increased with temperature. Ammonia in the examined range did not affect the disinfection kinetics. A chlorine contact tank with the injection chlorine level of 1 mg $Cl_2/L$ and the hydraulic retention time of 1.25 min is estimated to reduce total coliform from $1{\times}10^5MPN/mL$ to 1,000 MPN/mL at 271 mg SS/L, $15^{\circ}C$, and pH 8.0. Chlorine would be a proper option for the disinfection of CSO.

• Journal of Life Science
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• v.23 no.11
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• pp.1365-1370
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• 2013

Immobilized cellulase on weak ion exchange resin showed a typical Langmuir adsorption isotherm. Immobilized cellulase had better stability with respect to pH and temperature than free cellulase. Kinetics of thermal inactivation on free and immobilized cellulase followed first order rate, and immobilized cellulase had a longer half-life than free cellulase. The initial rate method was used to characterize the kinetic parameters of free and immobilized enzyme. The Michaelis-Menten constant $K_m$ was higher for the immobilized enzyme than it was for the free enzyme. The effect of the recirculation rate on cellulose degradation was studied in a recycling packed-bed reactor. In a continuous packed-bed reactor, the increasing flow rate of cellulose decreased the conversion efficiency of cellulose at different input lactose concentrations. Continuous operation for five days was conducted to investigate the stability of long term operation. The retained activity of the immobilized enzymes was 48% after seven days of operation.

• Korean Journal of Food Science and Technology
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• v.7 no.3
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• pp.148-153
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• 1975

Seven toxigenic molds isolated from deteriorated rice in Korea, Aspergillus clavatus, Asp. flavus var. columnaris, Asp. fumigatus, Asp. ochraceus, Penicillium citrinum, Pen. implicatum, and Pen. islandicum, were examined for their sensitivity toward Co-60 gamma rays for survival. Conidia of all tested species showed survival curves of sigmoidal type, from which decimal reduction doses were found to vary in the range of $14{\sim}33$ krad, induction doses, in the range of $12{\sim}56$ krad and inactivation factors at 200 krad, in the range of $4.6{\sim}12.8$, all at a dose rate of 11.56 krad/min. Dose rate effects on the radiosensitivity of Asp. flavus and Pen. islandicum conidia indicated that the higher dose rate (11.56 krad/min) caused decreases in decimal reduction doses as compared with the lower dose rate (2.67 krad/min).

• BMB Reports
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• v.32 no.3
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• pp.294-298
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• 1999

Myo-inositol monophosphate phosphatase is a key enzyme in the phosphoinositide cell-signaling system. Incubation of myo-inositol monophosphate phosphatase from porcine brain with N-bromosuccinimide (NBS) resulted in a time-dependent loss of enzyme activity. The inactivation followed pseudo-first-order kinetics with the second-order rate constant of $3.8{\times}10^3\;M^{-1}min^{-1}$. The time course of the reaction was significantly affected by the substrate myo-inositol-1-phosphate, which afforded complete protection against the loss of catalytic activity. Spectrophotometric studies indicated that about one oxindole group per molecule of enzyme was formed following complete loss of enzymatic activity. It is suggested that the catalytic function of myo-inositol monophosphate phosphatase is modulated by the binding of NBS to a specific tryptophan residue at or near the substrate binding site of the enzyme.

• Journal of Microbiology and Biotechnology
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• v.10 no.4
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• pp.441-448
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• 2000

The production and cation flux-mediated activation of the P-type ATPase in Helicobacter pylori was investigated. Using the polymerase chain reaction (PCR), the proton pump genotype of H. pylori was found to be positive for both F-type and P-type ATPases. Yet, their production in terms of enzyme specific activity varied substantially depending on H. pylori strains, ranging over 3-fold. Its main constituent appeared to be the P-type ATPase pool, in contrast to other common bacterial compositions. Interestingly, the F-type ATPase was observed only when intact H. pyloricells were exposed to pH 4.5 or above (37$^{\circ}C$ for 1 h). In contrast, significant amounts of the P-type ATPase still remained after 1 h of cell treatment even at pH below 4.5. By enriching the acidic medium with RPMI(pH 3.0), the P-type ATPase was stabilized, accompained by inactivation of the F-type ATPase. Using H. pylori membrane vesicles, it was found that ammionia-mediated cation flux increased the rate of ATP hydrolysis by the P-type ATPase. Accordingly, these data strongly suggest that the P-type ATPase is involved or functions as an effective regulator for the cation flux across the H. pylori membrane, thereby reducing the risk of excess proton influx.

• Journal of Microbiology and Biotechnology
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• v.5 no.1
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• pp.14-17
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• 1995

Endoglucanase gene of Pseudomonas sp. LBC505 was previously cloned in pUC19 to yield plasmid pLCl. The Pseudomonas sp. LBC505 endoglucanase gene was subcloned in a temperature-regulated Es-cherichia coli expression vector, pAS1, containing the leftward promoter $P_L$ of bacteriophage lambda. The level of gene expression was controlled by the thermal inactivation of the heat-sensitive lambda cI857 repressor. Best yield of endoglucanase was obtained by lowering the incubation temperature to $37^{\circ}C$ after induction at $42^{\circ}C$ for 1h. Under these conditions enzyme production continued for about 5h at a gradually decreasing rate. Ecoli harboring recombinant plasmid pASC10 expressed 4.3 times as much CMCase activity as E.coli containing pLCl. To enhance the expression level of endogl, ucanase gene, we have also changed the presumptive Shine-Dalgamo sequence (AGAGGT) of the gene to consensus sequence (AGGAGGT) by site-directed mutagenesis. The genes mutated were subcloned in pASl resulting in the formation of recombinant plasmid pASS50. E.coli harboring the plasmid pASS50 expressed 6.2-fold higher levels of CMCase activity than that of E.coli harboring pLC1.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8599-8604
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• 2016

Ovarian cancer is the main cause of mortality in gynecological malignancy and extensive studies have been conducted to study the underlying molecular mechanisms. The BRCA2 gene is known to be an important tumor suppressor in ovarian cancer, thereby BRCA2 alterations may lead to cancer progression. However, the BRCA2 gene is rarely mutated, and loss of function is suspected to be mediated by epigenetic regulation. In this study we investigated the methylation status and gene expression of BRCA2 in ovarian cancer patients. Ovarian cancer pateints (n=69) were recruited and monitored for 54 months in this prospective cohort study. Clinical specimens were used to study the in situ expression of aberrant BRCA2 proteins and the methylation status of BRCA2. These parameters were then compared with clinical parameters and overall survival rate. We found that BRCA2 methylation was found in the majority of cases (98.7%). However, the methylation status was not associated with protein level expression of BRCA2 (49.3%). Therefore in addition to DNA methylation, other epigenetic mechanisms may regulate BRCA2 expresison. Our findings may become evidence of BRCA2 inactivation mechanism through DNA methylation in the Indonesian population. More importantly, from multivariate analysis, BRCA2 expression was correlated with better overall survival (HR 0.32; p=0.05). High percentage of BRCA2 methylation and correlation of BRCA2 expression with overall survival in epithelial ovarian cancer cases may lead to development of treatment modalities specifically to target methylation of BRCA genes.

• Preventive Nutrition and Food Science
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• v.20 no.1
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• pp.60-66
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• 2015

The aim of this study was to determine the heat-penetration characteristics using stationary and rotary retorts to manufacture Kimchi soup. Both heat-penetration tests and computer simulation based on mathematical modeling were performed. The sterility was measured at five different positions in the pouch. The results revealed only a small deviation of $F_0$ among the different positions, and the rate of heat transfer was increased by rotation of the retort. The thermal processing of retort-pouched Kimchi soup was analyzed mathematically using a finite-element model, and optimum models for predicting the time course of the temperature and $F_0$ were developed. The mathematical models could accurately predict the actual heat penetration of retort-pouched Kimchi soup. The average deviation of the temperature between the experimental and mathematical predicted model was 2.46% ($R^2=0.975$). The changes in nodal temperature and $F_0$ caused by microbial inactivation in the finite-element model predicted using the NISA program were very similar to that of the experimental data of for the retorted Kimchi soup during sterilization with rotary retorts. The correlation coefficient between the simulation using the NISA program and the experimental data was very high, at 99%.

• KSBB Journal
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• v.25 no.1
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• pp.25-32
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• 2010

This study was carried out to evaluate the performance of three kinds of single process (electrolysis, UV and ultrasonic process) for the purpose of disinfection of Escherichia coli in water. Among the five kinds of electrode material, disinfection performance of Ir electrode was higher than that of the other electrodes. The order of disinfection performance for E. coli in single process lies in: electrolysis > UV $\gg$ ultrasonic process. Performance of the three single processes was increased with the increase of the electric power. Disinfection efficiency of the three processes was increased with the decrease of the pH. Disinfection of the UV process were decreased by the increase of NaCl dosage and air flow rate. However, ultrasonic process was not affected above two parameters. OH radical was not produced in UV and ultrasonic process. E. coli disinfection of the electrolysis process was well agreed with RNO degradation tendency, except pH.