• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.18-25
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• 2008

Pseudomonas sp. PRGB06, a bacterial strain isolated from diamondback moth (Plutella xylostella) gut, was examined for its plant growth promotion and biofertilizing traits. The bacteria growth was observed under various conditions of carbon sources, temperature, pH and salt concentrations. In addition, the mechanisms of antagonism and phosphate solubilization were investigated. The bacterial strain PRGB06, grew well using most of the tested carbon sources. The best growth was observed at $30^{\circ}C$ and pH 7. The inhibition of the pathogenic fungi was likely due to the volatile antifungal metabolite and ammonia gas produced by the bacteria. A significant positive relationship was found between the phosphate solubilization and acid production. When inoculated with PRGB06 in vitro and in gnotobiotic condition, red pepper and maize showed increase in root length, seedling vigor and dry bio-mass.

• Journal of Dairy Science and Biotechnology
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• v.21 no.2
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• pp.97-104
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• 2003

It is extremely important to destroy the antigenicity of milk proteins for dietetic treatment of infants with milk allergy. Enzymatic digestion of milk protein is not only effective for destroying antigenicity, but it also is less liable to alter the nutritive value. Bovine casein was hydrolyzed with eight different commercial proteases derived from bacterias or fungi, either individually or in combination to eliminate protein allergenicity. The average molecular weight of casein hyrdolysates determined by size exclusion chromatography is about 550${\sim}$2,300 dalton range. Antigenicity of the casein hyrdolysates was not detected by heterologous passive cutaneous anaphylaxis in guinea pig-rabbit antiserum system. The inhibition test on the enzyme-linked immunosorbent assay(ELISA) showed that the antigenicity of casein hydrolysates is lowed up to 1/8,000 than that of intact bovine casein. As the enzyme reaction was carried out by the combination of bacterial and fungal protease, casein hydrolysates showed much lower bitterness and antigenicity. It suggests that these hydrolysates will be applied to many kinds of foods including the development of hypo-allergenic infant formula.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.2
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• pp.92-103
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• 1993

A sunday system with a horizontal bin-type composter was constructed and operated to evaluate its composting performance for four days for each test in October, 1992. A sundry system is one of popular systems for composting livestock manure, of which main benefit is to utilize unlimited, clean, and free solar radiation. A rectangular concrete bin(composter) with dimension of 300cm(length) X90cm(width) X60cm(height) was bedded alternatively with four lanes of aeration pipes and heating pipes, and was insulated at three walls with 50mm styrofoam. Each aeration pipe of a diameter of 25mm had 4mm perforated holes at every 15cm longitudinally, and supplied air of about 2m$^3$/min to the composter to maintain aerobic condition . A stirrer rotating at 1 rpm made one round trip every 20 minutes on the conveying chain along the the length of the composter. Five tests (Test 1~Test 5) were implemented to evaluate the composting effectiveness of a sundry system with a horizontal bin-type composter. Treatments of two levels of the mixture ratio of swine manure and paper sludge cakes(manure : paper sludge cakes= 1 : 4 and 1 : 2) and two levels of the water content(W/C ; 70% and 50%) were made to test the significance of the physicochemical properties for decomposition of the mixture materials. Temperature, C/N ratio, water content, microbial activity of the composting materials were taken measurements to evaluate its performance with the lapse of composting time for tests. A small-scale sundry system with a bin-type composter did not appear to be an appropriate system for composting livestock manure. Since heat generation by the composting materials could not overcome heat loss due to areation in a small-scale composter, a proper thermal enviroment could not be maintained to propagate massively thermopilic microorganism relatively in a short period of time. Different from the result of Chol et al.(1992) 6), a temperature variation of the composting materials did not show the peak clearly and C/N ratio didn't lower with time as expected. Mesophilic microoragnism seemed to play an important role for decomposition of the mixture materials. A sundry system with a bin-type composter may be good for a large-scale livestock farm household which may produce enough animal manure. Therefore a decision should be made very carefully to choose a system for composting livestock waste.

• Food Engineering Progress
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• v.14 no.4
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• pp.359-366
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• 2010

Large-scale preparation steps of antithrombotic materials from wood ear mushroom (Auricularia auricular-judae) were established as follows. Grounded dry wood ear mushroom was extracted with 75% ethanol and its precipitate was extracted with $76^{\circ}C$ water for 2 hr followed by filter pressing. The filtrate was then concentrated by vacuum and extracted with 80% ethanol, and the resulting precipitate was then freeze-dried. The formula of the product was determined using consumer susceptibility tests as follows; mushroom extract 90.5%, high fructose corn syrup 2.0%, $\beta$-cyclodextrin 1.5%, fructo-oligosaccharide 2.0%, pear puree 4.0%. When the packed products were stored at 25, 37, or $45^{\circ}C$ for 8 weeks, there were no noticeable changes in water activity, moisture content, pH, and acidity. The viable cell number of total bacteria was slightly increased during the storage period at 25 and $37^{\circ}C$, The total bacteria were not detected in the product when stored at $45^{\circ}C$. When the product was injected intravenously into rat at the level of 1,000 mg/kg, antithrombotic activities such as activated partial thromboplastin time, thrombin time, prothrombin time, and FIB were increased when compared with the control group. When the product was administrated orally into rat at the level of 500 mg/kg, it showed the same antiplatelet activity to aspirin.

• Food Science and Industry
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• v.53 no.1
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• pp.69-83
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• 2020

For the development of the chitosan industry in Korea, the catch of red snow crabs caught on the east coast is rapidly decreasing. Therefore, it is urgent to develop raw materials that can replace the red snow crab as the top priority to solve the supply and demand problems, as well as wastewater treatment costs account for a large proportion of the cost of chitosan. In order to solve the problems, continuous research on biological extraction methods such as enzymatic extraction and microbial fermentation will increase production efficiency and lower unit cost as well as chemical extraction methods. Further efficient manufacturing method can be established. Establishing of novel techniques is indispensable for production of high-purity chitosan and the ability to regulate and separate the molecular weight, as well as joint research with industry, academia and research institute for the research and development of high-functional chitosan derivatives.

• Clean Technology
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• v.16 no.2
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• pp.88-94
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• 2010

The physiological roles of various wavelength of light emitting diode (LED) on ‘Hayward’ kiwifruit experiencing after-ripening were investigated. Various wavelengths from LED light source were irradiated on kiwifruits kept in plastic bags or under open air at $25^{\circ}C$. During two weeks of storage, firmness of Hayward kiwifruits was decreased by $25^{\circ}C$ treatment than by $4^{\circ}C$ treatment. In the $25^{\circ}C$ storage condition, the firmness of kiwifruits was decreased by the treatment of 380 nm UV and 470nm white LED light source. Sweetness of kiwifruits treated with 380 nm UV LED and dark condition at $25^{\circ}C$ increased higher than $15^{\circ}$Brix. The acidity of kiwifruits under open air was decreased 52% by incubating at $25^{\circ}C$ with 660 nm red LED treatment. The acidity of kiwifruits in plastic bags was decreased 52.6, 55.6, 52.8% by the treatment of 440 nm blue, 470 nm white and 660 nm red LED light source, respectively, compared to that of kiwifruits incubated in darkness at $25^{\circ}C$. Decreased acidity irradiated by 660 nm red LED light source can be applied for regulating periods of the kiwifruit after-ripening process. LED light sources emit very narrow wavelength with a power-saving mode, therefore, the usage of these LED light source for regulating the after-ripening process can be classified as a clean biotechnology producing safe and environment-friendly kiwifruits.

• Korean Journal of Ecology and Environment
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• v.56 no.1
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• pp.1-13
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• 2023

Targeting Microcystin (MC), which is most abundantly detected in the North-Han River water area, we analyzed the relationship between the MC biosynthesis gene (mcyA gene), cyanobacteria cell density, and MC concentration, derived an RNA-MC conversion formula, and derived the cyanobacteria. The concentration of MC present in cells was predicted. In the North-Han River waters, the mcyA gene was found mainly at downstream sites of the North-Han River after Muk-Hyeon Stream junction, and higher copy numbers were found on average than other sites. In the Uiam Lake waters upstream of the North-Han River, the mcyA gene copy number increased at the Kong-Ji Stream point, and after September, the mcyA gene copy number decreased throughout the North-Han River waters. The expression of the mcyA gene was concentrated in the short period of summer due to the spatio-temporal difference between upstream and downstream water bodies. The mcyA gene expression level was not only highly correlated with MC concentration, but also correlated with the cell density of Microcystis aeruginosa and Dolichospermum circinale, which are known to biosynthesize MC. Six conversion formulas derived based on the RNA-MC relationship showed statistical significance (p<0.05) and exhibited high correlation coefficients (r) of 0.9 or higher. The expression level of MC biosynthesis gene present in eRNA determines the synthesis of cyanotoxin substances in water, quickly quantifies gene activity, and can be fully utilized for early warning of MC development.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.593-602
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• 2004

A feeding trial was carried out to investigate the effect of supplemental complex probiotics on performances, physio-chemica1 properties of meat and inetestinal microflora in broiler chicks. Four hundred eighty broiler chickens, one days old with mixed sexes were fed one of four diets containing 0, 0.1, 0.2 and 0.4% complex probiotics for 7 weeks. There were four replicates with thirty chicks per pen. Diet contained ME 3,100, 3,l00kcal/kg, and CP 22.0, 20.0% for starting and finishing period, respectively. Body Weight gain of chicks fed the complex probiotics tended to increase from the frist week and all complex probiotics higher than control from the 4th week. Chickens fed the diets containing 0.2% probiotics had higher(P<0.05) than those fed the other levels from the 4th week to 5th week. Feed conversion also improved significantly(P<0.05) in the supplemental 0.2% probiotics from the 4th week to 5th week. In physio-chemica1 properties of meat, carcass rate increased significantly(P<0.05) in the supplemental 0.4% probiotics compared to that of control at 7 weeks overall means and abdominal fat pad rate increased significantly(P< 0.05) in the supplemental 0.2% probiotics compared to that of control. Cooking loss decreased significantly(P<0.05) in the supplemental all probiotics. But shear force increased significantly(P<0.05) in the supplemental 0.4% probiotics. The number of ileum and cecum Lactobacillus spp. tended to increase in the supplemental complex probiotics at 7 week of age, but was not significantly different. As the result, supplemental complex probiotics increased performance and physio-chemica1 properties of meat and the number of intestinal Lactobacillus of broiler chicks.

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.382-390
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• 2020

This study was carried out to evaluate the antimicrobial effect of red ginseng (Panax ginseng C.A. Meyer) against several foodborne pathogens including Staphylococcus aureus, Escherichia coli, Candida albicans and Aspergillus niger. The antimicrobial effect was determined by agar diffusion method using red ginseng extract, crude saponin and non-water-soluble fractions. Red ginseng extract showed antimicrobial effect against S. aureus, but not C. albicans or A. niger. The extract showed anti-bacterial activity at concentration above 30% against S. aureus, which cause both food poisoning and atophic dermatitis. Crude saponin showed antibacterial activity above 7.5% against the bacterium. However, the ginsenosides purified from crude saponin showed no antimicrobial activities at 100-200 ㎍/mL. To investigate the mode of growth inhibition, red ginseng extract and crude saponin were added to 0.85% NaCl solution containing S. aureus and then incubated at 35℃ for 12 h. The results showed that viable cells were rapidly reduced in above 10% concentration of red ginseng extract and above 2% of crude saponin, respectively. However, the crude saponin and red ginseng extract did not inhibit the bacterial cells completely at those same concentrations. On the other hand, whereas all non-water-soluble fractions showed inhibition zones above 10 mm against S. aureus, they showed no inhibition effects against E. coli, C. albicans or A. niger. The methanol fraction-1 (MF-1) showed the highest antibacterial activity against S. aureus, and the MIC (minimal inhibitory concentration) was 0.625 mg/mL. These results suggest that red ginseng extract, crude saponin and non-water-soluble fractions show selective antibacterial activity against S. aureus, and non-water-soluble fractions might be used as natural antibacterial agents.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.195-203
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• 2021

Aureobasidium pullulans, a black yeast, produces pullulan, a linear α-glucan composed of maltotriose repeating units linked by α(1→6)-glycosidic linkages. Pullulan can be widely used in food, cosmetic, and biotechnology industries. In this study, we isolated eight strains of A. pullulans from Forsythia koreana, Magnolia kobus DC., Spiraea prunifolia var. simpliciflora, Cornus officinalis, Cerasus, and Hippophae rhamnoides. Among them, A. pullulans MR was selected as the best pullulan producer. The effects of a carbon source, a nitrogen source, and pH on pullulan production were examined. The optimal cultivation conditions for pullulan production by A. pullulans MR were determined by response surface methodology as 15% sucrose, 0.4% soy peptone, and an initial pH of 7 at 26℃. Under these conditions, the predicted pullulan production was 47.6 g/L, which was very close to the experimental data (48.9 g/L).