• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.168-172
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• 2017

In this study, the fermentative characteristics of rye sourdough fermented with Omija extract were investigated. The pH and total titratable acidity, numbers of yeast and lactic acid bacteria, and expansion rate were measured. While the pH of Omija rye sourdough decreased from 5.60 to 3.86, the total titratable acidity significantly increased from 2.39 to 8.50 with fermentation time (p<0.05). The numbers of yeast and lactic acid bacteria significantly increased for 18 h of fermentation period (p<0.05). The expansion rate of Omija rye sourdough showed a maximum of 183%, more than 47% more than the highest value of rye sourdough (129%). These results suggest that the application of Omija extract for making sourdough could be a good way to decrease the sanitary risk especially for early stage of sourdough fermentation. In addition, Omija rye sourdough could contribute to improvement of baking quality such as volume increase and flavor improvement of rye bread.

• The Korean Journal of Food And Nutrition
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• v.19 no.1
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• pp.47-52
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• 2006

This study was carried out to improve the preservation and the functionality of chicken legs. Three precipitation solutions of common solution(A), herb solution(B) and herb solution containing chitosan(C) were prepared. The chicken legs were treated with A, B and C solution, respectively, during 4 hours. And the chicken legs treated with each solution were stored at $7^{\circ}C$ for 8 days. The quality changes of each groups were examined by pH, total bacteria, VBN(volatile basic nitrogen) values and sensory evaluation. The pH values of three groups were not different. Chicken legs treated with C solution showed the lowest VBN values and total bacteria cell count and the highest sensory scores in color and flavor.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.265-271
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• 1989

Bacteria isolated from Cheonsu Bay at 4 seasons were analyzed by numerical taxonomic method. Results of 48 morphological, physiological and biochemical tests showed different adaptability of bacteria to temperature in consequence with sampling season and isolated bacteria were able to survive at various environmental conditions, Identification results revealed that Enterobacteriaceae, Aeromonas, Pseudomonas and Vibrio were dominant genera in geterotrophic bacterial community. For each season, Aeromonas was most dominant in spring and autumn, Pseudomonas and Enterobacteriaceae in summer and winter, respectively. Cluster ananlysis was performed and all vacteria were clustered into 29 phenetic groups. Seasonal characteristics were distict in each group. Different physiological characteristics and species compositions for each season contribute to the stability and diversity of environmental ecosystem.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.828-833
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• 2000

The effect of treatments with alcohol, chitosan, or with both alcohol and chitosan for extending the shelf-life of Korean white rice cake and wet noodle was investigated by measuring quality changes such as total microbial count, pH, and sensory qualities. Total microbial counts for control, alcohol-treated, and 1% lactic acid-treated white rice cakes exceeded the initial putrefactive criterion level of $1{\times}10^{6}\;CFU/g$ at 6, 27 and 20 days of storage, respectively. However, total microbial count of the white rice cake treated with chitosan was still less than the criterion level even at 76 days of storage. In the case of wet noodle, total microbial counts of control and alcohol-treated groups exceeded the criterion level within 7 days of storage, while that of chitosan-treated group was far less than the criterion level even at the end of storage of 82 days. Chitosan treatment extended the shelf-lives of both white rice cake and wet noodle appreciably.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.150-155
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• 2013

We have conducted pyrosequencing for freshwater microbial community analyses. Fourteen sites along the Yeongsan river were selected for this study, and samples were collected monthly from May to July, 2012. Total 987,380 reads were obtained from 42 samples and used for taxonomic classification and OTU distribution analysis. Our results showed that high geographical and temporal variation in the phylum level bacterial composition, suggesting that microbial community is a very sensitive parameter affected by the surrounding environments including tributaries and land use nearby. In addition, we conducted an OTU-based Microbial Source Tracking to identify sources of fecal pollution in the same region. From this study Firmicutes was found to be the most influential taxa in this region. Here, we report that the use of pyrosequencing based microbial community analysis may give an additional information on freshwater quality monitoring, in addition to the currently used water quality parameters, such as BOD and pH.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.421-429
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• 2019

The purpose of this study was to investigate the effects of intestinal bacteria on the growth of enteric bacteria, especially infectious harmful bacteria such as food poisoning, gastritis and enteritis, and the growth of beneficial bacteria. By dividing the rat into three test groups; normal control group, Loperamide-treated group, and supercritical heat-treated radish complex extracts(HRE)-treated group, animal experiments were performed to inhibit the growth of harmful bacteria without affecting the growth of beneficial bacteria in the intestine. It was found that it can be usefully used as an effective and safe health food composition for improving intestinal function and bacterial intestinal disease. In particular, it can be concluded that supercritical heat-treated radish complex extract is a safe food that does not show any side effects even when taken for a long time.

• Journal of Sericultural and Entomological Science
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• v.36 no.1
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• pp.62-68
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• 1994

Isolation, indentification, bioassay and distribution of ice nucleation active(INA) bacteria were done on branch rot of mulberry which was severely developed after harvest of mulberry branches in autumn. Twelve isolates and two isolates out of thirty-six isolates had ice nucleation activity from -5$^{\circ}C$ to -1$0^{\circ}C$, and over -5$^{\circ}C$, respercively. Isolates which formed ice nucleation from -5$^{\circ}C$ to -1$0^{\circ}C$ were not inclined to injure tomato and corn seedlings. However, Two isolates, SE9316 and SE9338 which formed ice nucleation over -5$^{\circ}C$ injured mulberry, tomato and corn seedlings. SE9316 and SE9338 were identified as Pseudomonas syringae based on the morphological, cultural and biochemical characteristics. Populations of ice nucleation active bacteria, fluorecent pseudomonads, were higer in February and April, but they decreased in May. Populations decreased as they become distant from the center of the symptom. The bacterial populations of all sampling times and sites were higer than 105 cfu/g which was enough to induce frost injury.

• Journal of Life Science
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• v.30 no.3
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• pp.304-312
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• 2020

Agarase can be used in the field of basic science, as well as for production of agar-derived high-functional oligosaccharides and bioenergy production using algae. In 2012, we summarized the classification, origin, production, and applications of agar. In this paper, we briefly review the literature on the recombinant expression of agarases from 2012 to the present. Agarase genes originated from 19 genera, including Agarivorans, Flammeovirga, Pseudoalteromonas, Gayadomonas, Catenovulum, Microbulbifer, Cellulophaga, Saccharophagus, Simiduia, and Vibrio. Of the 47 recombinant agarases, there were only two α-agarases, while the rest were β-agarases. All α-agarases produced agarotetraose, while β-agarases yielded many neoagarooligosaccharides ranging from neoagarobiose to neoagarododecaose. The optimum temperature ranged between 25 and 60℃, and the optimum pH ranged from 3.0 to 8.5. There were 14 agarases with an optimum temperature of 50℃ or higher, where agar is in sol state after melting. Artificial mutations, including manipulation of carbohydrate-binding modules (CBM), increased thermostability and simultaneously raised the optimum temperature and activity. Many hosts and secretion signals or riboswitches have been used for recombinant expression. In addition to gene recombination based on the amino acid sequence after agarase purification, recombinant expression of the putative agarase genes after genome sequencing and metagenome-derived agarases have been studied. This study is expected to be actively used in the application fields of agarase and agarase itself.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.40-46
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• 2007

For restoration of disturbed ecosystem in Lake Paro, artificial floating island (AFI) was installed. Even though the lake water was oligo-mesotrophic, the macrophytes, such as Iris ensata, Iris pseudoacorus, Phragmites communis were growing well in the rubberized coconut fiber media. For elucidating this process, total bacterial numbers, active bacterial numbers and exoenzymatic activities of ${\beta}-glucosidase$ and phosphatase of pore water of media and lake water were analyzed. The average of total bacterial numbers, active bacterial numbers and exoenzymatic activities of ${\beta}-glucosidase$ and phosphatase were $28.6{\times}10^{6}\;cells/ml,\;22.7{\times}10^{6}\;cells/ml,\;452.9nM/L/hr,\;and\;16381.9nM/L/hr$ which were 10, 15, 22 and 38 times higher than those of lake water, respectively. Moreover, the total phosphorus and total nitrogen concentration of media showed high values of 0.82 mg/L and 7.0 mg/L, respectively, while those of lake water 0.07 mg/L and 2.3 mg/L. This results suggest that the bacteria was playing an important role for restoration of disturbed ecosystem with newly created microbial ecosystem in media of artificial floating island.

• Journal of Aquaculture
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• v.11 no.2
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• pp.203-212
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• 1998

As seed production program is growing prosperously in various fishes in southern Korea, disease problems in larval and juvenile stages have emerged as a new research object. The following results were obtained from investigation about environmental factors related to mass mortalities of young Kinki red seabream, Pagrus major in process of artificial seedling production. Total length of red seabream larvae hatched was 2.93mm, and became 18.83~20.12mm at day 40. The first noticeable mortality of red seabream larvae (7.98~9.37mm) occurred in 25~30 day-old fish with the survival rates of 59.8~60.3%. Thereafter the mortality of larvae decreased, survival rate was 20.5~25.45% in day 40. After 20~30 days, the quality of pond water was bellow II class. During the experimental period COD, $PO_4$-P, $NO_2$-N, $NO_3$-N and $NH_$-N increased up to 3, 7, 34, 6 and 8 times, respectively, compared to initial ones. The number of viable bacteria in pond water and seabream larvae were $6.3{\times}10^6$~$2.3{\times}10^7$ cfu/ml, 4.3~$7.4{\times}10^6$ cfu/g in day 25, respectively. Among the isolated bacteria from the diseased red seabream in day 25, Vibrio spp. was considered to be the causative organism. External symptoms of this disease were floated, spined near the surface and inflated abdomen. When the isolated strain of the Vibrio was bathed to seabream larvae, $LD_50$ of seabream larvae was over $10^6$ cfu/ml of Vibrio spp.