• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.2
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• pp.120-132
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• 1993

A continuous hollow fiber membrane reactor(CHFMR) was developed and optimized for the production of yellowfin sole(Limanda aspera) skin gelatin hydrolysates using trypsin. The results were summerized as follows: The $K_m$ value of the CHFMR was 2.4 times higher than that of the batch reactor, indicating reduced enzyme affinity for the substrate. The $K_2$ value of the CHFMR was 8.5 times lower than that of the batch process, showing a significant reduction in trypsin activity in the CHFMR. The optimum operating conditions for the CHFMR process were $55^{\circ}C$, pH 9.0, flux 7.79 ml/min, residence time 77min, and trypsin to substrate ratio, 0.01(w/w) After operating for 60min under the above conditions, $79\%$ of the total amount of initial gelatin was hydrolysed. Enzyme leakage was observed through the 10,000 MWCO membrane after the 20min of reactor operation, while none occurred after 5hr. Total enzyme leakage was about $12.95\%$ at $55^{\circ}C$ for 5hrs. However, there was no apparent correlation between enzyme leakage and substrate hydrolysis. The membrane has a significant effect on trypsin activity loss for 60min of the CHFMR operation. The CHFMR operating with the membrane lost $34\%$ of the initial activity versus a $23\%$ loss of activity after 3hr in the continuous reactor lacking the hollow fiber membrane. The measurement of fouling property showed that relative flux reduction was $91\%$ and flux recover rate was $92\%$ at $10\%$ substrate solution. The productivity(378.85mg product/mg enzyme) of the CHFMR was more than 4 times higher than that of the batch reactor at $55^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.3
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• pp.309-319
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• 1996

Properties as related to the utilization of the crude proteases extracted from the muscle and viscera of fish (2 dark fleshed lish; anchovy, Engraulis japonica, and gizzard-shad, Clupanoda punctatus; 2 white fleshed fish; seabass, Lateolabrax japonicus, and sole, Pleuronichthys cornutus) were studied. Proteolytic activity of the muscle protease was slightly inhibited with the increase of sodium chloride concentration and it was apparent against the yellowtail myofibrillar protein than casein substrate. Proteolytic activities of the seabass and sole visceral crude protease were inhibited to 50 to $60\%\;by\;25\%$ of sodium chloride, but those of anchovy and gizzard-shad viscera crude enzymes were not influenced by sodium chloride. The vacuum freeze-dried crude protease and glycerol-mixed crude pretense of gizzard-shad and seabass muscles were almost lost their activities on the 16th week of storage, while those from the viscera of the fish were relatively stable. Degradation of the yellowtail myofibrillar protein by the anchovy muscle and viscera crude pretenses rapidly proceeded in the beginning of the reaction and the degraded products were mainly distributed in the range of 6 to 15 kDa electrophoretically.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.4
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• pp.13-16
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• 1982

The hydrolytic conversion of sawdust was studied by sulfuric acid-enzymatic and sodium hydroxide-enzymatic treatments. Sugars were identified by paper chromatography and quantified colorimetrically. Sawdust yielded dextrose and xylose in concentrations ranging from 3.01 to 3.64 and 3.48 to 6.61 grams per 100g. Under optimum conditions, the total concentration of sugars was 10.7 grams per 100 grams.

• Korean Journal of Agricultural Science
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• v.21 no.2
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• pp.142-147
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• 1994

Characteristics of TNP-cellulose which prepared from carboxymethyl cellulose powder, CM32, as substrate for cellulase activity assay were investigated. Enzymatic hydrolysis of TNP-cellulose occured on the cellulose moiety but not on amide bonds, following Michaelis-Menten kinetics. Three cellulase preparations from Trichoderma viride, Aspergillus niger, and Cellulomonas sp. were tested for their pH and temperature dependences and compared with the method determining the increase in reducing power. The enzyme activity was found to have the same temperature range in both methods, however the pH range was broadened in the case of using TNP-cellulose as substrate. The colorimetric method for cellulase assay using TNP-cellulose as substrate was compared with the other methods: one based on determination of the increase in reducing power; and the other based on determining the decrease in viscosity of Na-CM-cellulose solution. The activities measured by the colorimetric method showed a linear correlation with the enzyme concentration of certain range in all three enzymes tested, and the activity values were proportional to those obtained from the other methods. Depending on the enzyme, however, the activity values from this method were not always in proportion to those from the viscometric method. suggesting that this method was not specific for determination of the endo-type cellulase.

• Journal of Life Science
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• v.20 no.11
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• pp.1582-1588
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• 2010

A new alginate lyase gene of marine bacterium Streptomyces sp. M3 had been previously cloned in pColdI vector and transformed into E. coli BL21 (DE3). In this study, M3 lyase protein without signal peptide was overexpressed by induction with IPTG and purified with Ni-Sepharose affinity chromatography. The absorbance at 235 nm of the reaction mixture and TLC analysis showed that M3 alginate lyase was a polyG-specific lyase. When M3 lyase was assayed with substrate for 10 min, optimum pH and optimum temperature were pH 9 and $60^{\circ}C$. For the effect of 1mM metal ion on M3 lyase activity, $Ca^{++}$ and $Mn^{++}$ ions increased the alginate degrading activity by two-fold, whereas $Hg^{++}$ and $Zn^{++}$ ions inhibited the lyase activity completely. $Mg^{++}$, $Co^{++}$, $Na^+$, $K^+$, and $Ba^{++}$ did not show any strong effects on alginate lyase activity.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.410-413
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• 2000

Lab-scale trickling bioreactor(TBR) containing the biofilm of Pseudomonas cepacia G4 was developed for the treatment of trichloroethylene(TCE) in a waste gas stream. The effect of phenol feeding on the efficiency of TCE biodegadation in TBR was investigated with the change of inlet phenol concentration from 0 to 4.71 ppm. When 0.94 ppm of phenol was supplied, the best performance of TBR was maintained with the TCE removal efficiency of 58.1%. These results showed that the appropriate supply of phenol could stimulate TCE removal efficiency in TBR.

• Applied Biological Chemistry
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• v.35 no.6
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• pp.501-506
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• 1992

Pepsin-catalyzed hydrolysis and plastein reaction were carried out to prepare plastein product from soymilk residue protein. Conditions required for optimal hydrolysis of soymilk residue protein and subsequent plastein production were investigated. The optimum substrate concentration, enzyme-substrate ratio, pH, reaction temperature and incubation time for hydrolysis were 3%, 1/50, 1.7, $45^{\circ}C$ and 24 hours, respectively. Plastein formation from peptic hydrolysate of soymilk residue protein was most effective at substrate concentratin of 40%, pH 4 and $45^{\circ}C$. Reaction time of 18 hours and enzyme-substrate ratio of 1/100 were selected for plastein production. Electrophoresis of the products revealed that protein-like substances of high molecular weight were produced from the plastein reaction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.2
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• pp.39-46
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• 1982

A model of substrate removal by rotating discs has been developed for a better understanding of the process, and the performance of the system has been evaluated under steady and unsteady state. The model was constructed based upon mass transfer of the substrate from the bulk solution to the biofilm and a simultaneous removal of the substrate by the biomass. The model is composed of a few sets of differential equations representing mass balance within the elements of a liquid film and a biofilm, and in the bulk solution. Substrate removal efficiency of the process is largely dependent on a diffusion coefficient of the substrate within the biofilm and a maximum rate of substrate removal of the biomass. The efficiency is affected to a greater extent when the substrate concentration is low and the maximum substrate removal rate is high. The efficiency increases proportionally with increasing film depth when the biofilm is shallow, however, the rate of increase gradually decreases with an increase of the film depth. As the film reaches a limiting depth, the efficiency remains constant. Unlike the steady state, the effluent quality is affected by the tank volume under dynamic state. Increasing tank volume decreases peak concentration of the effluent under peak loading. Additional tank volume provides a buffer capacitya.gainst a peak loading and the holding tank behaves like an equalization tank.

• Microbiology and Biotechnology Letters
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• v.44 no.2
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• pp.130-139
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• 2016

A bacterial strain, producing an excellent lipolytic enzyme, was isolated from the intestinal tracts of an earthworm (Eisenia fetida). The strain was identified as Aeromonas hydrophila by phenotypic, chemotaxonomic characteristics and 16S ribosomal DNA analysis, and was designated as Aeromona hydrophila PL43. The lipolytic enzyme from A. hydrophila PL43 was purified via 35−45% ammonium sulfate precipitation, DEAE-sepharose fast flow ion-exchange, and sephacryl S-300HR gel filtration chromatography. The yield of the purified enzyme was 3.7% and 2.5% of the total activity of crude extracts with p-nitrophenyl butyrate (pNPB) and p-nitrophenyl palmitate (pNPP) as substrates, respectively. The molecular weight of the purified enzyme was approximately 74 kDa using gel filtration, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and zymography. The optimal activity of purified enzyme was observed at 50℃ and pH 8.0 using pNPB, and 60℃ and pH 8.0 using pNPP. The purified enzyme was stable in the ranges 20− 60℃ and pH 7.0−10.0. The activity of purified enzyme was inhibited by PMSF, pepstatin A, Co²⁺, Cu²⁺, and Fe²⁺, but was recovered by metal chelating of EDTA. The K_m and V_max values of the purified enzyme were 1.07 mM and 7.27 mM/min using pNPB and 1.43 mM and 2.72 mM/min using pNPP, respectively.

• Journal of Soil and Groundwater Environment
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• v.10 no.3
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• pp.38-45
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• 2005

The feasibility of stimulating in situ aerobic cometabolic activity of indigenous microorganisms was investigated in a trichloroethylene (TCE)-contaminated aquifer. A series of single-well natural drift tests (SWNDTs) was conducted by injecting site groundwater amended with a bromide tracer and combinations of toluene, oxygen, nitrate, ethylene and TCE into an existing monitoring well and by sampling the same well over time. Three field tests, Push-pull Transport Test, Drift Biostimulation Test, and Drift Surrogate Activity Test, were performed in sequence. Initial rate of toluene degradation was much faster than the rate of bromide dilution resulting from natural groundwater drift, indicating stimulation of indigenous toluene-oxidizing microorganisms. Transformation of ethylene, a surrogate probing overall activity of TCE transformation, was also observed, and its transformation results in the production of ethylene oxide, suggesting that some tolueneoxidizing microorganisms stimulated may express a orthomonooxygenase enzyme. Also in situ transformation of TCE was confirmed by greater retardation of TCE than bromide after the stimulation of toluene-oxidizing microorganisms. These results indicate that, in this environment, toluene and oxygen additions stimulated the growth and aerobic cometabolic activity of indigenous microorganisms expressing orthomonooxygenase enzymes. The simple, low-cost field test method presented in this study provides an effective method for conducting rapid field assessments and pilot testing of aerobic cometabolism, which has previously hindered application of this technology to groundwater remediation.