• Resources Recycling
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• v.24 no.2
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• pp.46-54
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• 2015

In this study, an applicability of thermal pretreatment for primary and secondary sludge, which are generated in a sewage treatment plant, was evaluated. The efficiency and charateristics was investigated with each sludge after pretreatment under the condition of $100{\sim}220^{\circ}C$ for 30 minutes. As the result, it was found that $SCOD_{Cr}$, $NH_4{^+}$, VFAs concentrations increased as the pre-treatment temperature increased. For COD solubilization, it was also highly dependent on an increase of temperature resulting in acceleration on hydrolysis and acid fermentation. In the BMP (Biochemical Methane Potential) experiment, for the primary sludge, it showed the higher biogas production rate at a temperature of $220^{\circ}C$, however, the effect was insignificant (5.6%). Whereas, for the secondary sludge, the increase on biogass production rate was 38.8% ($180^{\circ}C$) and this means that the secondary sludge is more suitable for an applicability of thermal pretreatment.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.204-210
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• 2015

Makgeolli is made from rice or flour, yeast, and nuruk, a fermentation starter. The flavor of makgeolli is affected by sugars, amino acids, organic acids and volatile flavor compounds produced by various microorganisms. In this study, lactic acid bacteria (LAB) were isolated from unsterilized makgeolli samples collected from several provinces in Korea, and then later identified. Under anaerobic conditions, LAB density ranged from $5.0{\times}10^6$ to $1.5{\times}10^8CFU/mL$; yeast density ranged from $2.5{\times}10^7$ to $1.5{\times}10^8CFU/mL$. Of the LAB isolated from makgeolli, 1,126 were analyzed using restriction fragment length polymorphism (PCR-RFLP) analysis of 16S rRNA, which allowed for classification into five groups. Of the 1,126 LABs tested, 130 produced ${\gamma}$-aminobutyric acid (GABA).

• Journal of Life Science
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• v.17 no.11
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• pp.1555-1561
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• 2007

In order to know the effects of scoria, germanium, charcoal, ginger, stevia, and CLA(Conjugated Linoleic Acid) as biologically active materials on pathogenic microbes and rumen anaerobic microbes, the growth rate of pathogens (including Escherichia coli O157, Salmonella paratyphi, Listeria monocytogenes and Staphylococcus aureus) and in vitro lumen microbial growth, gas production, ammonia concentration, carboxymethyl-cellulase (CMCase) activity, and microbial populations were investigated. The growth of pathogenic microbes was inhibited by the supplement of 0.10% ginger. Ginger had powerful antimicrobial properties on all the pathogens used in this experiments. Additionally in the antibacterial assay by paper disc method, we could observe the clear zone of similar area with the positive control(antibiotics) for E. coli as applied with the 10% stevia or the 10% CLA only. The supplements of ginger, stevia and CLA in vitro rumen fermentation inhibited populations of rumen bacteria and protozoa. Particularly supplement of ginger resulted in remarkable reduction of the protozoa population, which means it might serve as a source inhibiting material of methane creation in the rumen.

• The Korean Journal of Food And Nutrition
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• v.28 no.2
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• pp.171-177
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• 2015

Sodium butyrate is a short-chain fatty acid derivative found in foods, such as Parmesan cheese and butter and is produced by anaerobic bacteria fermentation of dietary fibers in the large intestine. There have been reports that butyrate prevented obesity, protected insulin sensitivity, and ameliorated dyslipidemia in dietary obese mice. This study investigated the effects of sodium butyrate on fasting blood glucose level and serum lipid profile in streptozotocin(STZ)-induced diabetic mice. Male C57BL/6 mice were fed AIN-93G for four weeks prior to intraperitoneal injections with STZ (100 mg/kg body weight). Diabetic mice had supplements of 5% sodium butyrate for four weeks. The 5% sodium butyrate diet significantly improved fasting blood glucose level and lipid profile in STZ-induced diabetic mice. Inflammation has been recognized to decrease beta cell insulin secretion and increase insulin resistance. Circulating cytokines can directly affect beta cell function, leading to secretory dysfunction and increased apoptosis. Thus, anti-inflammatory therapies represented a potential approach for the therapy of diabetes and its complications. In this animal study, the 5% sodium butyrate supplementation also inhibited inflammatory cytokine production in STZ-induced diabetic mice. These results suggested that sodium butyrate can be a potential candidate for the prevention of diabetes and its complications.

• Journal of Life Science
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• v.31 no.5
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• pp.520-526
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• 2021

Microbial protein is one of the sources of protein in the rumen and can also be the source of glutamate production. Glutamic acid is used as fuel in the metabolic reaction in the body and the synthesis of all proteins for muscle and other cell components, and it is essential for proper immune function. Moreover, it is used as a surfactant, buffer, chelating agent, flavor enhancer, and culture medium, as well as in agriculture for such things as growth supplements. Glutamic acid is a substrate in the bioproduction of gamma-aminobutyric acid (GABA). This review provides insights into the role of glutamic acid and glutamic acid-producing microorganisms that contain the glutamate decarboxylase gene. These glutamic acid-producing microorganisms could be used in producing GABA, which has been known to regulate body temperature, increase DM intake and milk production, and improve milk composition. Most of these glutamic acid and GABA-producing microorganisms are lactic acid-producing bacteria (LAB), such as the Lactococcus, Lactobacillus, Enterococcus, and Streptococcus species. Through GABA synthesis, succinate can be produced. With the help of succinate dehydrogenase, propionate, and other metabolites can be produced from succinate. Furthermore, clostridia, such as Clostridium tetanomorphum and anaerobic micrococci, ferment glutamate and form acetate and butyrate during fermentation. Propionate and other metabolites can provide energy through conversion to blood glucose in the liver that is needed for the mammary system to produce lactose and live weight gain. Hence, health status and growth rates in ruminants can be improved through the use of these glutamic acid and/or GABA-producing microorganisms.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.341-351
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• 2022

Among various environmental stresses, humid stress lacks mechanisms and biochemical understanding compared to drought, low temperature, and high salt stresses. The aim of this study was to investigate enzyme activity of field crops under humidity stress. Results of this study could be used as basic data for understanding humidity stress and early diagnosis. Growth and enzyme activities of sesame, perilla, red beans, sorghum, and beans as major field crops in Korea when flooded were investigated. It was confirmed that growths of both shoots and roots were retarded. In plants, anaerobic fermentation occurred due to flooding stress, which increased the activity of alcohol dehydrogenase (ADH) compared to the control group. Increases of reactive oxygen species (ROS) were also observed. All flooded plants showed increased peroxidase (POD) activity and lipid peroxidation. Their dyeing strength was darker than that of the control group, even in 3,3'-diaminobenzidine (DAB) staining. Since enzyme activity changes in plants appear relatively faster than changes in phenotype at the ground level, they could be used as biomarkers for early diagnosis of humidity stress in crops.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.231-237
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• 1999

It is very distinctive that sigumjang meju was produced with smoking after molding. Every shapes of traditional sigumjang meju gathered from Kyeongsangbukdo were doughnut types. Fermentation time were $60{\sim}90$ days. Aerobic bacteria were $6.8{\times}10^7\;cfu/g$, and anaerobic bacteria, yeasts, molds count $3.2{\times}10^6\;cfu/g,\;1.0{\times}10^6\;cfu/g\;and\;4.0{\times}10^6\;cfu/g$, respectively. Analysis showed: moisture content, $10.5{\pm}2.6%$; fat content, $2.9{\pm}1.1%$; protein content, $8.3{\pm}0.7%$; ash content, $3.8{\pm}0.7%$; pH, $6.0{\pm}0.5$; L-value, $54.5{\pm}4.7$; a-value, $+3.3{\pm}0.7$; and b-value, $+10.7{\pm}2.0$. K content was the most in quantity among the minerals in sigumjang meju. Maltose was most abundant component among the tested sugars followed by mannitol. Total content of amino acid was $1524.9{\pm}1295.3\;mg%$. Proline was the most abundant component among the amino acids. The ratio of essential amino acid was $30.0{\pm}12.9%$. The principal fatty acids were 18:2, 18:1 and 16:0. Saturated fatty acid and mono unsaturated fatty acid were $23.2{\pm}1.9%\;and\;23.5{\pm}5.2%$, respectively. The PUFA/SFA was $2.3{\pm,}0.3$ which higher than 1.

• Food Science and Preservation
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• v.24 no.6
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• pp.865-870
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• 2017

Yogurt is produced by fermentation of milk using bacteria known as "yogurt cultures". Most of these bacteria are probiotics such as Lactobacillus delbrueckii subsp. bulgaricus, Lb. rhamnosus, Streptococcus thermophilus, and Bifidobacterium. The domestic fermented milk market is increasing, and about 30 companies are producing yogurt. The purpose of this study was to analyze the quality characteristics of domestic commercial liquid yogurt. Total 30types of commercial yogurts were sampled and their physicochemicial properties, including pH, sugar content, acidity, viscosity, and microbial characteristics of lactic acid bacteria counts, were measured. Commercial liquid type yogurt showed a pH of 4.5, sugar content of 7.4-21.2%, total acid content of 0.4-0.9%, and viscosity of 0.1-250 cP. In terms of microbial populations, lactic acid bacteria counts were 7.2-11.3 log CFU/mL and anaerobic lactic acid bacteria counts were 8.0-11.5 log CFU/mL. The quality characteristics differed depending on the constituents of the sample and the microorganisms used. These results are related to the quality characteristics of yogurts and are useful for identifying new trends in the domestic fermented milk industry.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.203-210
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• 2001

In order to environmentally use wood chips manufactured from low valued forest resources by forest tendering, wood chips were used for the evaluation on chips characteristics, decomposition capability of organic wastes, and field experiment and determination of conditions for decomposer. Bioclusters manufactured by Cryptomeria japonica, commercially available wood chips in Japan, showed higher pore ratio, water reservation and water resistance, and higher cellulose content with lower hot water solubles than domestic wood chips. The useful size of wood chips for swine manure decomposition was 10 (length) ${\times}$ 5 (width) ${\times}$ 2 (thickness) mm, and cellulose contents and alkali solubles of Pinus densiflora and Populus tomentiglandulosa were similar to those of bioclusters. According to the decomposition ratio depending on wood species, it was ordered as Pinus densiflora > Pinus koraiensis > Cryptomeria japonica. The swine manure decomposition ratio depending on treatment hours by Pinus koraiensis was constant with the ratio of 15 to 16 g per hour by 1 kg of chip, indicating of daily swine decomposition amount of 390 kg by 1 ton of chips which was equal to the amount of daily swine manure production by 70 swines. Analyzing by long term used wood chips during 40 days treatment, the treated wood chips characteristically showed stable total nitrogen content, suitable pH, high accumulation of inorganic contents such as calcium, phosphorus, potassium and sodium, and no odor. During winter, the inner temperature of decomposer was kept at $43^{\circ}C$, but air bubble was occurred due to high pH and viscosity of swine manure. The most appropriate mixing ratio between wood chips and swine manure was 1 versus 2 or 3, and at more than ratio 1 versus 3, ammonia gas was caused because of anaerobic fermentation status by high moisture content of wood chips. The mixing interval of decomposer was 3 mins. per hour for the best swine decomposition.

• Journal of Animal Science and Technology
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• v.53 no.2
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• pp.161-169
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• 2011

Methane production during anaerobic fermentation in the rumen represents an energy loss to the host animal and induces emissions of greenhouse gases in the environment. Our study focused on comparison in methane production from growing Korean native steers fed different grain sources. Six Hanwoo steers (BW = $180.6{\pm}3.1$ kg) were fed, on a DM basis (TDN 2.80 kg), 40% timothy and 60% barley concentrate (Barley) or corn concentrate (Corn), respectively, based on the Korean Feeding Standards. Each period lasted 18 days including a 14-day adaptation and a 4-day measuring times. The steers were in the head hood chamber system (one cattle per chamber) during each measuring time to measure heat and methane production per day. Different grain sources did not affect digestibilities of dry matter, crude protein, crude fiber, crude fat, NDF, ADF and nitrogen-free extract. The mean methane concentrations per day were 202.0 and 177.1 ppm for Barley and Corn, respectively. Methane emission averaged 86.8 and 77.7 g/day for Barley and Corn, respectively. Methane emission factor by maintenance energy requirement for the growing steers fed barley based concentrate was higher than the steers fed corn based concentrate (Barley vs. Corn, 31.7 kg $CH_4\;head^{-1}\;yr^{-1}$ vs. 28.4 kg $CH_4\;head^{-1}\;yr^{-1}$). Thus, methane conversion rate was 0.065 (6.5%) and 0.055 (5.5%) for Barley and Corn, respectively.