• Magazine of the Korean Society of Agricultural Engineers
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• v.16 no.4
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• pp.3600-3610
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• 1974

Experimental work of batch-type dryer was conducted to develop its optimurm operating conditions by analyzing the major factors which affect the drying performance. A laboratory batch-type dryer was constructed and tested for various levels of heated-air rates, and depths of grain deposit. Tong-il rice variety having the initial moisture content of approximaely 23 per cent in wet basis was used for the experiment. The criteria selected for establishing the optimum operating condition were the drying performance rate, the thermal efficiency, and the operational cost of the dryer. The results of the study are summarized as follows: 1. The performance rate of dryer for a specific operating condition was defined as total amount of material dried per hour when the moisture content of grains in the upperlayer reaches to 16 per cent in wet basis. The optimum operating conditions as viewed in the rate of drying performance could be justified by functional realtionship between the depth of grain deposit and air flow rate. In other words, there was a definite depth of grain deposit for a given air-rate which make the dryer performance maximum. The optimum grain depth for the batch-type dryer with 3.3㎡ loading area and with the attached axial fan was about 35cm. 2. The thermal efficiency for the dryer was evaluated by the ratio of the latent heat required to evaporate the grain moisture to the heat input required to raise the ambient air-temperature to 40 degree centigrade. The optimum operating condition as viewed in term of thermal efficiency analyzed was that grater depth and lower air flow-rate may be desirable. This condition is contracted with the optimum condition as viewed by the dryer performance rate. 3. The annual operating cost of batch-type dryer was analyzed for different annual hour of use and for different operation condition. The optimum condition as viewed in terms of operating cost was almost identical to one as viewed in terms of dryer performance rate. Therefore, the most economical use of batch-type dryer for the same annual operating hours can be obtained when the dryer operated in the condition of maximum dryer performance rate. Increasing the annual operating hour may be desirable to cut down the dryer operation cost, since the annual hour of dryer use is much sensitive to the operating cost than any peractical conditions of dryer operation. 4. The most desirable operational condition as justified by combining all the criteria, dryer performance rate, thermal efficiency and annual operating cost, could be concluded to operate the dryer in the condition of maximum performance rate. The condition in general is identical to the lowest operation cost for a given annual operating hour.

• The Korean Journal of Pesticide Science
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• v.9 no.1
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• pp.60-69
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• 2005

The herbicide molinate has been detected with high frequency in the main river during the growing season in Korea. To elucidate the exposure of molinate in agricultural environment, the persistence and the degradation characteristics of molinate were investigated in paddy ecosystems. The half-lives of molinate were 4.1 days with soil aquatic system, and 4.2 days in only aquatic system. Initial dissipation rate of molinate in water was greater with soil aquatic system than that of only aquatic system. Photolysis of molinate was occurred about 31.0% of molinate treated in pure water, when irradiated at 5,530 $J/cm^2$ by the xenon lamp, but its hydrolysis was stable. For the accelerated photolysis of molinate in aqueous solution, several photosensitizers were screened, showing that the hydroperoxide($H_2O_2$) and acetone were prominent among the chemical tested. When hydroperoxide and zinkoxide(ZnO) were used as photosensitizer, their photolysis were accelerated greater than 98% and 58% in aqueous solution, respectively. Elution rate of molinate as granular formulations in aqueous system was more than 90% in 30 hour at $35^{\circ}C$. Molinate concentration pattern in paddy water was rapidly decrease from treatment till 7 days in paddy rice field and its half-lives were 3.7 days($Y=1.9258{\times}e^{-0.1865X}$(r=-0.9402)).

• Microbiology and Biotechnology Letters
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• v.5 no.1
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• pp.18-23
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• 1977

Experiments were carried out to pursue the availability and the feasibility of utilizable cellulosic materials as substrate for the production of cellulosic single cell protein. The resuluts were obtained as fellows. 1. Effects of carbolydrates as a sole carton source on the growth of Cellulomonas flavigena KIST 321 were examined. The result showed that cellulose and xylose would be most utlizable for cell mass production. 2. Alkaline treated waste papers and clothes resulted in good growth of the organism than intact ones did. However the waste papers as substrate of cellulosic fermentation were not digestible, even if the meterial was treated with alkalies. 3. Rice straw, rape straw and panic grass appeared to be good substrates for the cell mass production. 4. Leaves were proved to be a good substrate for the cell mass production, but wood sawdust was hardly digested by merely alkaline treatment. 5. When cellulosic wastes as the substrate were examined into the concentration of alkaline solution, the result suggested that the best productivity of cell mass from cellulosic materials was obtained on treatment with 0.8∼1.0％ NaOH solution. 6. The productivity of cell mass was increased by washing out with water after alkaline treatment of newspaper, pine sawdust, lime sawdust and pine leaf.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.373-378
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• 2010

Studies on standardization and quality upgrade of nuruk which is a basic component in brewing are required to increase the quality level of Korean traditional rice wines and to develop the technology for practical use of it. It is important to isolate best strains, to improve the properties and effectively preserve them for brewing industry. In this study, 16 commercial nuruk samples were obtained from the commercial markets located in Chungcheong areas in Korea. 174 fungal strains were isolated from the samples on DG18 medium using a dilution plating method and then screened for enzyme activity and acid production. The active strains were identified based on the morphological characteristics and ITS sequence analysis. Out of 174 strains, 12 strains showed high amylase activity. Especially, Rhizopus sp. CN084, CN174, Aspergillus sp. CN161 and Mycocladus sp. CN042 showed high saccharogenic power and dextrinogenic enzyme activity on cooked wheat bran medium. On the other hand, Aspergillus sp. CN010, CN161, Rhizopus sp. CN105, CN168 and Rhizomucor sp. CN088 produced high acid production on the same medium. Our results showed that the active strains may be used as microbial sources for nuruk starter with good quality in brewing.

• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.893-902
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• 2011

Endophytic fungi are little known for their role in gibberellins (GAs) synthesis and abiotic stress resistance in crop plants. We isolated 10 endophytes from the roots of field-grown soybean and screened their culture filtrates (CF) on the GAs biosynthesis mutant rice line - Waito-C. CF bioassay showed that endophyte GMH-1B significantly promoted the growth of Waito-C compared with controls. GMH-1B was identified as Penicillium minioluteum LHL09 on the basis of ITS regions rDNA sequence homology and phylogenetic analyses. GC/MS-SIM analysis of CF of P. minioluteum revealed the presence of bioactive $GA_4$ and $GA_7$. In endophyte-soybean plant interaction, P. minioluteum association significantly promoted growth characteristics (shoot length, shoot fresh and dry biomasses, chlorophyll content, and leaf area) and nitrogen assimilation, with and without sodium chloride (NaCl)-induced salinity (70 and 140 mM) stress, as compared with control. Field-emission scanning electron microcopy showed active colonization of endophyte with host plants before and after stress treatments. In response to salinity stress, low endogenous abscisic acid and high salicylic acid accumulation in endophyte-associated plants elucidated the stress mitigation by P. minioluteum. The endophytic fungal symbiosis of P. minioluteum also increased the daidzein and genistein contents in the soybean as compared with control plants, under salt stress. Thus, P. minioluteum ameliorated the adverse effects of abiotic salinity stress and rescued soybean plant growth by influencing biosynthesis of the plant's hormones and flavonoids.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.407-412
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• 2014

A number of Saccharomycopsis fibuligera strains that can hydrolyse and utilize starch as a carbon source were isolated from nuruk, a traditional Korean starter for rice wine fermentation, and their specific growth rates on starch-containing medium were compared to choose the prominent strain. S. fibuligera strain MBY1320 showed a higher growth rate at $42^{\circ}C$ than that of strain S. fibuligera KCTC7806, indicating that S. fibuligera MBY1320 has more thermo-tolerant machinery for starch hydrolysis and utilization than KCTC7806. Although the activity of ${\alpha}$-amylase at $30^{\circ}C$ was significantly lower for S. fibuligera MBY1320 than KCTC7806 (3,812.5 U vs. 14,878.5 U), S. fibuligera MBY1320 showed a much higher glucoamylase activity at $42^{\circ}C$ than S. fibuligera KCTC7806 (5,048.9 U vs. 13,152.3 U). Thus, a new S. fibuligera strain, with a higher starch-hydrolysing activity at elevated temperatures than that of other types of strain, this study reports.

• Journal of Microbiology and Biotechnology
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• v.28 no.6
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• pp.976-986
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• 2018

Knowledge about the gut bacterial communities associated with insects is essential to understand their roles in the physiology of the host. In the present study, the gut bacterial communities of a laboratory-reared insecticide-susceptible (IS), and a field-collected insecticide-resistant (IR) population of a major rice pest, the brown planthopper Nilaparvata lugens, were evaluated. The deep-sequencing analysis of the V3 hypervariable region of the 16S rRNA gene was performed using Illumina and the sequence data were processed using QIIME. The toxicological bioassays showed that compared with the IS population, IR population exhibited 7.9-, 6.7-, 14.8-, and 18.7-fold resistance to acephate, imidacloprid, thiamethoxam, and buprofezin, respectively. The analysis of the alpha diversity indicated a higher bacterial diversity and richness associated with the IR population. The dominant phylum in the IS population was Proteobacteria (99.86%), whereas the IR population consisted of Firmicutes (46.06%), followed by Bacteroidetes (30.8%) and Proteobacteria (15.49%). Morganella, Weissella, and Enterococcus were among the genera shared between the two populations and might form the core bacteria associated with N. lugens. The taxonomic-to-phenotypic mapping revealed the presence of ammonia oxidizers, nitrogen fixers, sulfur oxidizers and reducers, xylan degraders, and aromatic hydrocarbon degraders in the metagenome of N. lugens. Interestingly, the IR population was found to be enriched with bacteria involved in detoxification functions. The results obtained in this study provide a basis for future studies elucidating the roles of the gut bacteria in the insecticide resistance-associated symbiotic relationship and on the design of novel strategies for the management of N. lugens.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.3
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• pp.153-166
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• 1991

Laver is sea weeds that might have been eaten by Korean people since ancient times. The begining of laver culture is not known exactly, but it appears to be prehistoric age. Some laver culture complexes have been built in southern coastal sea of Korea around 1910. This paper was considered about the origin and development process of Korean laver culture industry by investigating Korean and Asian old books concerned. The results are as follows. 1. According to the Korean old books ralated, the name of laver is classified into 10kinds. Gim and Hae-I were called by Korean. Gim means weeds and Hae-I means the manufactured laver by cutting and drying like paper sheet. Ja-Chae and Hae-Tae are come from Chinese, however they are commonly called by Korean, Japanese and Chinese. Rest six names are come from Chinese botany. 2. As Chinese used laver as medicine for wen, scrofula, fever, vomiting, diarrhoea and. so on, they didn't regard it as foods and took into account an warning by Chinese botany that they could take ill when overeating it. On the other as Korean people have eaten it with pleasure nevertheless the Chinese warning, various foods using laver have been developed. The typical food is rice covering laver sheet. It is also popular to Japanese. 3. Laver culture can be carried out in all coastal seas around Korean peninsula, the best sea area for it is the middle west of south sea. 4. Seopkkoji type is a laver culture method that when branches of tree are put in tidal flat laver sporules are attached and gronm on them. It was begun by Hae-Jak Kun(a group of fishery slaves) on Kwang-Yang bay the most suitable for. laver growth at the beginning of King $Sung-long(1469{\~}1481)$. It is assumed that when Hae-Jak Kun set Oe-Jeon(a sort of fixing fishing gear) to catch tributary fish for king, they could find grown laver attached on Oe-Jeon and invent Seopkkoji type for exclusive laver culture. That was carried out 200 fears earlier than in Japan. Dde-Bal type is more advanced and productive laver culture method with thinly spilt bamboo tied like screen(one end fixed on bottom and other end set free in water), It is assumed that Dde-Bal type was begun in Wan-Do county in King Chull-Jong(1830). All laver culture methods developed were transfered to Japan.

• Korean Journal of Food Science and Technology
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• v.37 no.1
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• pp.61-66
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• 2005

Korean traditional rice wine Takju and Yakju were manufactured using 2-step-brewing method. To investigate microflora involved in fermentation step, number of microorganisms, pH, titratable acidity, and alcohol contents of Takju and Yakju were measured. In Takju and Yakju, although not significantly, $1.1{\times}10^{8}$ and $2.0{\times}10^{6}\;CFU/mL$ lactic acid bacteria at initial stage of second fermentation decreased to $8.3{\times}10^{6}\;and\;1.0{\times}10^{4}\;CFU/mL$ at the end of second fermentation, respectively. For Takju, micrococci and yeast occupied 80 and 20% at initial stage of second fermentation, whereas bacteria and yeast occupied 35 and 65% at the end of second fermentation, respectively. Yeast occupied 88% throughout the second fermentation of Yakju. The main yeast isolated from both Takju and Yakju was identified as Saccharomyces cerevisiae using API 20C AUX kit. The yeast strain Candida magnoliae was also detected during fermentation of Takju and Yakju.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.2
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• pp.233-240
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• 2007

The purpose of this study was to evaluate the effect of different saccharides on the quality of apricot sulgidduk. Appearance color of honey-added group as compared to other samples in apricot sulgidduk were preferable and scanning electron microscopy exhibited smaller pores. pH and acidity of white-added group immediately after preparation were higher than those of other groups. Higher moisture contents of honey-added groups during storage were found but total bacterial counts immediately before storage were 1 log cycle lower than that of other samples. The highest 'L' values were found for white sugar added group but the highest 'a' and 'b' were for yellow sugar-added sample. In mechanical characteristics of apricot sulgidduk for 48 hrs during storage at $20^{\circ}C$, hardness, gumminess and brittleness were higher in oligosaccharide-added sample as compared to other samples, while cohesiveness and springiness were the highest in honey-added group. In sensory evaluation of the sulgidduk, honey-added group obtained the highest score in color, sweet taste, moisture, after swallowing and overall quality (p<0.05) These results suggest that apricot sulgidduk with honey can be used as commercially successful rice cakes.