• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1071-1078
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• 2007

Using a 50-1 airlift bioreactor, for the effective production of tylosin from Streptomyces fradiae TM-224 using raw cornmeal as the energy source, various environmental factors were studied in flask cultures. The maximum tylosin concentration was obtained at $32^{\circ}C$ and pH between 7.0 and 7.5. When seed was inoculated after 24 h of culture, the maximum tylosin concentration, 5.7 g/l, was obtained after 4 days of culture. Various concentrations of raw cornmeal were tested to investigate the optimum initial concentration for the tylosin production. An initial raw cornmeal concentration of 80 g/l gave the highest tylosin concentration, 5.8 g/l, after 5 days of culture. Of the various nitrogen sources, soybean meal and fish meal were found to be the most effective for the production of tylosin. In particular, with the optimal mixing ratio, 12 g/l of soybean meal to 14 g/l of fish meal, 7.2 g/l of tylosin was obtained after 5 days of culture. To compare raw cornmeal and glucose for the production of tylosin in the 50-1 airlift bioreactor for 10 days, fed-batch cultures were carried out under the optimum culture conditions. When raw com meal was used as the energy source, the tylosin production increased with increasing culture time. The maximum tylosin concentration after 10 days of culture was 13.5 g/l, with a product yield from raw cornmeal of 0.123 g/g of consumed carbon source, which was about 7.2 times higher than that obtained when glucose was used as the carbon source.

• Korean Journal of Food Science and Technology
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• v.27 no.2
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• pp.251-256
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• 1995

Sucrose is added to feed materials to alter the taste and texture of extruded products. Emulsifier can affect extrudate properties by forming complexes with amylose during extrusion-cooking. These ingredients may improve the cell structure and texture of cornmeal extrudates obtained by using $CO_{2}$ as a bubble forming agent. The objective of this study was to evaluate effects of sucrose (5% and 10%) and glyceryl monostearate (GMS) (0.75% and 1%) on properties of cornmeal extrudates produced with $CO_{2}$ at injection pressures from 1.04 to 2.07 MPa. Dough temperature increased and die pressure decreased when $CO_{2}$ was injected into barrel. The addition of sucrose to cornmeal resulted in decreasing dough temperature, specific mechanical energy (SME) input, and die pressure. SME input was not significantly influenced by GMS addition but die pressure was decreased when GMS was added. Extrudate density was decreased over observed $CO_{2}$ injection compared to GMS. WSI was significantly decreased with the addition of GMS. Paste viscosity was also decreased with addition of sucrose or GMS, but significant differences of paste viscosity among $CO_{2}$ injection pressures were not found. Stucture forming and texture of cornmeal extrudates by $CO_{2}$ injection was improved by adding GMS.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.947-954
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• 1997

Selected physical properties of cornmeal extrudates fortified with dairy products and extrusion process by $CO_2$ gas injection were analysed. Dairy products including whole milk powder, whey protein concentrate non-fat dry milk, and sodium caseinate were tested at the addition of 10% and 20%, based on cornmeal weight. $CO_2$ gas was injected to the barrel at the pressure of 0.7 and 1.4 MPa. Specific mechanical energy (SME) input was decreased by the addition of dairy products. Sodium caseinate had a little effect on decreasing the SME input, however whole milk powder tremendously reduced SME input when the concentration increased. An increase in milk product content resulted in increasing the piece density at the injection pressure of 0.7 MPa. At both 10% and 20% milk product content, the piece density was lowest at the injection pressure of 0.7 MPa. The sectional expansion index was highest at the injection pressure of 0.7 MPa. However, the specific length was constantly increased with the increase in $CO_2$ injection pressure. Water absorption index was decreased and water solubility index was increased by the addition of milk products. The injection pressure of $CO_2$ was optimum at 0.7 MPa. The addition of whole milk powder limited to puff the melt, but the other milk products tested resulted in puffing with $CO_2$ injection to 1.4 MPa.

• The Korean Journal of Mycology
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• v.3 no.2
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• pp.7-12
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• 1975

Three species of Pythium previously not recorded in Korea were found during 1975. Pythium spinosum Sawada was isolated from diseased cabbage seedlings, P. myriotylum Dreschl. was isolated from kidney bean and P. butleri Subramanium from cucumber, spinach, red bean and radish. Pathogenicity of isolates of P. butleri and P. myriotylum was confirmed in pathogenicity tests but P. spinosum appeared to be non-pathogenic. Several isolates failed to sporulate satisfactorily on cornmeal agar and some produced degenerate oogonia after sub-culturing on this medium. Sunflower seed agar was found to be a suitable alternative medium. The validity of previous records of P. debaryanum Hess in Korea is discussed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.292-298
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• 2001

This study was conducted to investigate physicochemical properties of extrudates combining 4 levels of squid (0, 3, 5 and 7%) with 3 levels of defatted soy flour (0, 5, and 10%). Blends were adjusted to moisture content of 27% and then extruded in a single-screw laboratory extruder at 170rpm screw speed and 16$0^{\circ}C$ barrel temperature. The extruded materials were dried at 6$0^{\circ}C$ for 8hr to a moisture content of 3~4% and refrigerated at 4$^{\circ}C$ for 12 hour before examination for textural properties, expansion ratio, bulk density, shear force and Hunter color. Expansion ratio of extrudates decreased as squid content increased whereas bulk density and shear force increased. Expansion ratio of extrudates was not significantly different by defatted soyflour level. Bulk density of products decreased as defatted soyflour content increased but shear force of products increased as defatted soyflour content increased. In scores of sensory hedonic evaluation of snacks, appearance, flavor, texture and overall acceptability values had lowered as squid level increased. Therefore, according to materials contents on extrudates increased, nutritional contents of this products increased and also shear force and bulk density in physical properties increased whereas expansion ratio decreased.

• The Korean Journal of Mycology
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• v.51 no.2
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• pp.101-109
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• 2023

A fungal strain designated KNUF-21-66Q1 was isolated from soil in Chungcheongbuk Province, Korea. Moderate growth of colonies was observed on potato dextrose agar, oatmeal agar (OA), malt extract agar, and cornmeal agar media at 25℃, and the detailed morphology was examined on OA medium. The colonies on OA medium were flat, had entire margin, hyaline, and yellow concentric rings in 3-4 weeks. Conidiomata were pycnidial, solitary or clustered, globose to subglobose, black-brown, and 300-500 ㎛ in diameter. Conidiogenous cells were smooth, hyaline, globose to ampulliform, and 6.0-9.0×3.0-6.0 ㎛ in size (n=15). Conidia were hyaline to pale brown, slightly golden, obovoid to slightly ellipsoidal, smooth, guttulate, and 3.0-4.7×2.1-3.3 ㎛ in size (n=100). The strain was confirmed based on phylogenetic analysis using internal transcribed spacer regions, the partial 28S rDNA of large subunit, and β-tubulin gene sequences. The morphological observations and phylogenetic analysis revealed that the strain KNUF-21-66Q1 was similar to the previously described Paraconiothyrium kelleni. To our knowledge, this is the first report of P. kelleni in Korea.

• The Korean Journal of Mycology
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• v.50 no.4
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• pp.319-329
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• 2022

In July 2020, wilting symptoms were observed among adzuki bean plants (Vigna angularis var. angularis L.) in the fields in Yeosu, Korea. Infected plants showed yellowing of leaves, browning inside the stems, splitting of stem bark, and wilting. When these plants were uprooted, their roots were found to be brown. The fungal pathogens NC20-737, NC20-738, and NC20-739 were isolated from symptomatic stem and root tissues. These pathogens were identified as a Fusarium fujikuroi species complex based on their morphological characteristics. Molecular identification was performed using the DNA sequence of translation elongation factor 1 alpha and the RNA polymerase II second largest subunit regions. The nucleotide sequences of all three isolates were similar to the F. fujikuroi reference isolates NRRL 13566 and NRRL 5538 of the National Centre for Biotechnology Information GenBank. A pathogenicity test was conducted by the soil inoculation method with cornmeal sand inoculum. Approximately 3 weeks after inoculation, symptoms were observed only in the inoculated adzuki bean seedlings. To the best of our knowledge, this is the first report of Fusarium root rot caused by F. fujikuroi in adzuki beans, both in Korea and worldwide.

• The Plant Pathology Journal
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• v.35 no.6
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• pp.674-683
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• 2019

Some species of the Trichoderma genus are reported as the major problem in oak wood mushroom production in Korea. In spite of economic loss by the fungi, scientific information on airborne Trichoderma species is not much available. To generate information for disease management development we analyzed airborne Trichoderma. A total of 1,063 fungal isolates were purely obtained from indoor air sampling of cultivation houses used for oak wood mushroom using sawdust media. Among the obtained isolates, 248 isolates were identified as Trichoderma fungi including T. harzianum, T. atroviride, T. citrinoviride, and T. pseudokoningii, by morphological and molecular analysis. T. harzianum was dominant among the four identified species. All the four Trichoderma species grew fast on solid nutrient media tested (potato dextrose agar [PDA], malt extract agar [MEA], Czapek's Dox + yeast extract agar [CYA] and cornmeal dextrose agar). Compact mycelia growth and mass spore production were better on PDA and CYA. In addition, T. harzianum and T. citrinoviride formed greenish and yellowish mycelium and spores on PDA and CYA. Greenish and yellowish pigment was saturated into PDA only by T. pseudokoningii. These four Trichoderma species could produce extracellular enzymes of sawdust substrate degradation such as β-glucosidase, avicelase, CM-cellulase, amylase, pectinase, xylanase, and protease. Their mycelia inhibited the growth of oak wood mushroom mycelia of two tested cultivars on dual culture assay. Among of eleven antifungal agents tested, benomyl was the best to inhibit the growth of the four Trichoderma species. Our results demonstrate that the airborne Trichoderma fungi need to be properly managed in the cultivation houses for safe mushroom production.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.646-650
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• 1998

Mycological characteristics of Phytophthora nicotianae var. nicotianae SPC10 (A1 type) causing Phytophthora rot of strawberry and the resistances of 11 strawberry cultivars against the pathogen were examined. Optimum temperature for the mycelial growth of the pathogen was obtained in the range of 30~35$^{\circ}C$, and the growth was completely stopped under 13$^{\circ}C$ or over 42$^{\circ}C$. Aerial mycelia were abundant on oatmeal agar (OMA), V-8 juice agar (V8A) and lima bean agar (LBA) medium, although there were slight differences, however, on cornmeal agar (CMA) medium, it was a shape of stellate without aerial mycelia. The colony shape on potato dextrose agar (PDA) medium was rough and irregular whereas the mycelial growth was slow, and some aerial mycelia were only produced in the middle of PDA medium. Optimum temperature for sporangial formation was 3$0^{\circ}C$, and zoospores were mostly released at $25^{\circ}C$ from the sporangia. Sporangia were more produced in C/Z solution with pH 5. 0~6.$0^{\circ}C$ than sterilized distilled water (DSW) and distilled water (DW), and zoospores were also released much more than other solutions. Eleven strawberry cultivars such as Reiko, Hokowase, Eyeberry, Akaneko, Sistakara, Toyonoka, Nyoho, Sulhong, Suhong, Myhong and Wonkyo #3104 revealed the disease incidence up to 88.9~100% by the leaf inoculation with mycelial disk. However, Nyoho and Suhong showed higher level of resistance against the pathogen by root inoculation.