• Journal of the Korean Society of Food Science and Nutrition
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• v.1 no.1
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• pp.51-62
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• 1972

In Korea, fermented fish has been playing an important role as a preserved and flavor rich food. It is said that the digestion of fish protein is due to both action of intrinsic (autolytic enzymes) and bacterial enzymes in fish. The mass production of fermented fish has been impeded since traditional method of fermentation requires a long duration for a complete digestion. A high concentration of salt and unsanitary condition are also considered disadvantages of the old method. To improve the quality of the product and to develop mechanized process of fermentation, fermentors which have such control device as temperature, pH and agitation control system have been urgently needed. In this study, a model design of a fermentor is studied. The calculation was based on the optimum conditions for enzymatic hydrolysis of fish protein which involve temperature, pH, viscosity and other factors.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.2
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• pp.127-132
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• 2014

The effect of thermal pretreatment conditions on hydrolysis characteristics of dairy manure and sawdust mixtures has been evaluated. Thermal pretreatment temperature varied between 35 and $120^{\circ}C$ and the period of the treatment changed between 30 and 1440min (24h). As thermal pretreatment temperature and duration increased, organic material solublization rates were improved. Maximum solubilizations of chemical oxygen demand (SCOD), carbohydrates, and volatile fatty acids(VFAs) were observed when dairy manure treated for one day at $120^{\circ}C$. Although one day treatment duration at $120^{\circ}C$ showed the highest SCOD, soluble carbohydrates, and VFAs concentration, its hydrolysis rate was only about 12%. The results reveal that the thermal pretreatment conditions tried in this study are not enough to solubilize the organic matter contained in dairy manure and sawdust mixtures. In order to maximize hydrolysis performance, the further research needs to determine the factors influences on organic material solubilization in addition to thermal pretreatment temperature and duration.

• Journal of the Korean Wood Science and Technology
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• v.51 no.4
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• pp.270-282
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• 2023

Lower termites need symbiotic microbes for cellulose digestion. Elizabethkingia miricola strain BM10 has been proposed as a symbiotic microbe that assists in low-temperature digestion and metabolism of Reticulitermes speratus KMT1, a termite on Bukhan Mountain, Seoul, Korea. In E. miricola strain BM10, β-glucosidase genes expressed at 10℃ were identified, and the psychrophilic enzymatic characteristic was confirmed by heterogeneously expressed proteins. Crude β-glucosidase in the culture broth of E. miricola strain BM10 showed specific enzymatic properties, and its substrate affinity was 4.69 times higher than that of Cellic CTec2. Among the genes proposed as β-glucosidase, two genes, bglB_1 and bglA_2, whose gene expression was more than doubled at 10℃ than at 30℃, were identified. They were heterogeneously expressed in Escherichia coli and identified as psychrophilic enzymes with an optimal reaction temperature of about 20℃-25℃. In this study, E. miricola strain BM10, a symbiotic bacterium of lower termites, produced psychrophilic β-glucosidases that contribute to the spread of the low-temperature habitat of a lower termite, R. speratus KMT1.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.11
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• pp.618-626
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• 2016

The influence of ferric ion ($Fe^{+3}$) on bioelectrochemical anaerobic digestion for sewage sludge was explored at ambient temperature ($25^{\circ}C$). Before the addition of ferric ion, the removal of volatile solids (VS) was 65.9% and the specific methane production rate was 370 mL/L/d. After the addition of ferric ion (200 ppm) to feed sludge, the bioelectrochemical anaerobic digester was more stable in the state variables including pH, alkalinity, COD and VFAs, and the VS removal and specific methane production rate were increased to 69.8% and 396 mL/L/d, respectively. However, the methane content in biogas was slightly reduced by the addition of ferric ion, indicating that the activity of planktonic anaerobic bacteria (PAB) was more improved after the addition of ferric ion. The dominances of syntrophic bacteria (Cloacamonas) and hyrolytic bacteria (Saprospiraceae, Ottowia pentelensis) in the PAB were increased by the addition of ferric ion. The addition of ferric ion improved the performance of bioelectrochemical anaerobic digestion for sewage sludge at ambient temperature.

• Korean Journal of Environmental Agriculture
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• v.35 no.2
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• pp.128-136
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• 2016

BACKGROUND: Hydrothermal carbonization reaction is the thermo-chemical energy conversion technology for producing the solid fuel of high carbon density from organic wastes. The hydrothermal carbonization reaction is accompanied by the thermal hydrolysis reaction which converse particulate organic matters to soluble forms (hydro-thermal hydrolysate). Recently, hydrothermal carbonization is adopted as a pre-treatment technology to improve anaerobic digestion efficiency. This research was carried out to assess the effects of hydro-thermal reaction temperature on the methane potential and anaerobic biodegradability in the thermal hydrolysate of organic sludge generating from the wastewater treatment plant of poultry slaughterhouse .METHODS AND RESULTS: Wastewater treatment sludge cake of poultry slaughterhouse was treated in the different hydro-thermal reaction temperature of 170, 180, 190, 200, and 220℃. Theoretical and experimental methane potential for each hydro-thermal hydrolysate were measured. Then, the organic substance fractions of hydro-thermal hydrolysate were characterized by the optimization of the parallel first order kinetics model. The increase of hydro-thermal reaction temperature from 170℃ to 220℃ caused the enhancement of hydrolysis efficiency. And the methane potential showed the maximum value of 0.381 Nm³ kg^-1-VS_added in the hydro-thermal reaction temperature of 190℃. Biodegradable volatile solid(VSB) content have accounted for 66.41% in 170℃, 72.70% in 180℃, 79.78% in 190℃, 67.05% in 200℃, and 70.31% in 220℃, respectively. The persistent VS content increased with hydro-thermal reaction temperature, which occupied 0.18% for 170℃, 2.96% for 180℃, 6.32% for 190℃, 17.52% for 200℃, and 20.55% for 220℃.CONCLUSION: Biodegradable volatile solid showed the highest amount in the hydro-thermal reaction temperature of 190℃, and then, the optimum hydro-thermal reaction temperature for organic sludge was assessed as 190℃ in the aspect of the methane production. The rise of hydro-thermal reaction temperature caused increase of persistent organic matter content.

• Food Science of Animal Resources
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• v.34 no.3
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• pp.280-286
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• 2014

This study investigated the effects of cooking methods on the digestibility of lipids and formation of cholesterol oxidation products (COPs) in pork, during in vitro human digestion. Pork patties were cooked using four different methods (oven cooking, pan frying, boiling, and microwaving), to an internal temperature of approximately $85^{\circ}C$. The digestibility of pork patties were then evaluated, using the in vitro human digestion model that simulated the composition (pH, minerals, surfaceactive components, and enzymes) of digestive juices in the human mouth, stomach, and small intestine. The total lipid digestibility was higher after microwave cooking, whereas pan-frying resulted in lower in vitro digestibility, compared to the other cooking methods. The microwaving method followed by in vitro digestion also showed significantly higher content of free fatty acids and thiobarbituric acid reactive substances (TBARS), compared to the other cooking methods; whereas, the pan frying and boiling methods showed the lowest. Cholesterol content was not significantly different among the cooked samples before, and after in vitro human digestion. The formation of COPs was significantly higher in the microwave-treated pork samples, compared to those cooked by the other methods, which was consistent with the trend for lipid peroxidation (TBARS). We propose that from the point of view of COPs formation and lipid oxidation, the pan-frying or boiling methods would be useful.

• Journal of Life Science
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• v.14 no.2
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• pp.309-314
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• 2004

Cyclic AMP receptor protein (CRP) is involved in the transcriptional regulation of more than 100 genes in E. coli. CRP dimer is converted into active form via the sequential conformation change of cAMP binding pocket, hinge region and HTH DNA binding motif by binding of cAMP. The temperature gradient gel electrophoresis (TGGE) was applied to CRP protein to know whether it was an efficient technique to study the conformational transitions and the thermal stability. TGGE showed the unfolding process of wild-type and S83G CRP proteins with the temperature gradient set from 29 to 71$^{\circ}C$ on nondenaturing polyacrylamide gel. Melting temperature (Tm) was 57$\pm$1 and 55$\pm$1$^{\circ}C$ for wild-type and S83G CRP, respectively in acidic buffer[89.8 mM Glycine and 24 mM Boric acid (pH 5.8)].

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.1
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• pp.75-83
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• 2004

Temperature-phased anaerobic digestion (TPAD), anaerobic sequencing batch reactor (ASBR), and co-digestion technologies were combined together in order to overcome low efficiencies of conventional anaerobic sewage sludge digestion processes. In the performance, TPAD-ASBR process showed high VS removal efficiency over 60% up to the organic loading rate (OLR) of 2.7 g VS/L/d. The first-stage of TPAD-ASBR and control system played a most significant role in VS destruction and methane production. Methane production rate (0.79 l $CH_4/L/d$) of the system was higher than that (0.59 l $CH_4/L/d$) of the control system. The substrate characteristics of the sewage sludge, such as low VS concentration (1.5%, w/w) and biodegradability, were properly improved by the addition of food waste as a co-substrate, leading to more efficient VS removal and methane production. With several track studies, it was revealed that the independent solid retention time (SRT) of those systems prevented untreated particles from outflowing and also, extended the retention time of the active biomass for further degradation. Consequently, it was confirmed that the sequencing batch operation of the TPAD process using co-substrate was a promising alternative for the recycling of sewage sludge with low VS content.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.27-40
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• 2022

In this study, the anaerobic digestion potential and thermo-chemical pre-treatment were evaluated for efficient anaerobic co-digestion of dewatered sludge(DS) and food waste(FW). As a result, the degradable organic matter concentration and methane yield of FW were evaluated to 2.2 and 1.3 times higher than that of DS, respectively. In order to increase the amount of biogas production, it was determined that it is desirable to increase the mixing ratio of FW. The efficiency of thermo-chemical pre-treatment was evaluated for the reaction temperature, NaOH concentration, reaction time and mixture ratio. As a result of evaluation through pre-treatment efficiency and dehydration capacity, the optimum pre-treatment conditions were evaluated as follows: reaction temperature 140℃, NaOH concentration 60 meq/L, reaction time 60 min, mixture ratio 1:5(DS:FW). The gas production rate and methane yield increased 1.6 and 1.5 times, respectively, compared to before and after applying the optimum pre-treatment. Therefore, it is necessary to increase the mixing ratio of food waste for efficient anaerobic co-digestion of DS and FW. and it is necessary to increase the solubilization efficiency of waste by application of pre-treatment.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.3
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• pp.149-158
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• 2005

This paper describes design, fabrication, and application of the silicon based temperature controllable micro reactor. In order to achieve fast temperature variation and low energy consumption, reaction chamber of the micro reactor was thermally isolated by etching the highly conductive silicon around the reaction chamber. Compared with the model not having thermally isolated structure, the thermally isolated micro reactor showed enhanced thermal performances such as fast temperature variation and low energy consumption. The performance enhancements of the micro reactor due to etched holes were verified by thermal experiment and numerical analysis. Regarding to 42 percents reduction of the thermal mass achieved by the etched holes, approximately 4 times faster thermal variation and 5 times smaller energy consumption were acquired. The total size of the fabricated micro reactor was $37{\times}30{\times}1mm^{3}$. Microchannel and reaction chamber were formed on the silicon substrate. The openings of channel and chamber were covered by the glass substrate. The Pt electrodes for heater and sensor are fabricated on the backside of silicon substrate below the reaction chamber. The dimension of channel cross section was $200{\times}100{\mu}m^{2}$. The volume of reaction chamber was $4{\mu}l$. The temperature of the micro reactor was controlled and measured simultaneously with NI DAQ PCI-MIO-16E-l board and LabVIEW program. Finally, the fabricated micro reactor and the temperature control system were applied to the thermal denaturation and the trypsin digestion of protein. BSA(bovine serum albumin) was chosen for the test sample. It was successfully shown that BSA was successfully denatured at $75^{\circ}C$ for 1 min and digested by trypsin at $37^{\circ}C$ for 10 min.