• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.449-453
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• 1990

This study was attempted to obtain the efficient milk-clotting enzyme from microorganisms as a rennet subtitute. Fungi which showed the formation ability of the milk-clotting enzyme were selected out from samples of soil hay and wastes etc. Among these isolated fungi, strain no. C-7 which had presented higher value in the ratio of milk-clotting activity to proteolytic activity was selected. The hyphae of this strain was white to gray and no septa. A single sporangiophore which stand erectly above growing hyphae was monomucor type without branching. A globose sporangium was developed at the tip of each sporangiophore. The suitable temperature and pH for the growth of no. C-7 was 20-$30^{\circ}C$ and pH 3.0-8.0 respectively. These morphological and physiological characteristics implied that strain no. C-7 was Mueor mucedo.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.161-168
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• 1999

A series of centrifuge model tests were performed in order to investigate the behaviors of various tunnel linings. A 1/100-scaled aluminum and hydrostone horseshoe tunnel linings with a radius km, height km were buried in a depth of C/D=3 with dry Joomunjin standard sand, the relative density of which was 86%. Bending moments and thrusts along the tunnel circumference were measured by 12 strain gages. Earth pressures in soil and on lining were estimated by pressure transducers, ground surface settlements at center and edges by using LVDTs. Average Ko(coefficient of earth pressure at rest) was 0.39 for the model sand. The structural behaviors of lining depended on its damaged conditions. But, as a rule, on the crown, the tensile circumferential strain of lining occurred at the inner surface, and the compressive at the outer surface, then positive bending moment was created at the crown. The circumferential strain of the inner surface on the springline was tensile, and the outer compressive, so negative bending moment was measured at the springline. For hydrostone linings, cracks initiated at the inner surface on the crown, and the outer on the springline over average 40g.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.460-465
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• 2003

A bacterium, named as strain KL34, producing extracellular pectinase was isolated from soil. The mophological cheracteristics of the isolated bacterium were gram-negative, rod-shaped and endospore unformed. Production of pectinase of strain KL34 was induced only by polygalacturonic acid added to the culture media as a sole carbon source. Pectinase activity of KL34 reached a maximum value in the culture conditions of pH 8.5 at $25^{\circ}C$. Optimal medium for pectinase production was determined to the composition of 2% polygalacturonic acid, 0.25% yeast extract, 0.02% $K_2HPO_4$, 0.02% $CaCl_2$, and 0.05% KCl per liter. The pectinase activity in the culture supernatant reached the highest amount of 54 U/ml after 3 days cultivation in the optimal media.

• KSBB Journal
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• v.25 no.3
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• pp.230-238
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• 2010

A microbial strain having high keratinase activity was isolated from the soil of poultry factories of Gyeonggi or Chungcheong-do. The isolated strain was identified as Bacillus sp. based on its morphological and biochemical characteristics. In this study, the optimal conditions for the production of keratinase by this strain were investigated. The optimal medium composition for the keratinase production was determined to be 3.5% chicken feather as carbon source, 1.0% tryptone as organic nitrogen source, 1.0% $KNO_3$ as inorganic nitrogen source and 0.05% KCl, 0.05% $KH_2PO_4$, 0.03% $K_2HPO_4$ as mineral source and 0.01% yeast extract as growth factor. The optimal temperature and pH was $40^{\circ}C$ and 8.5 with shaking culture (200 rpm), respectively. The maximum keratinase production reached to 123 units/ml after 42 hr of cultivation under the optimal condition. When the hair was used as the sole carbon source, the maximum enzyme activity was 88 units/ml after 120 hr and in this case, the hair added in the medium was not degraded completely but got thinner than the control by 20%.

• Journal of Microbiology and Biotechnology
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• v.6 no.1
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• pp.12-18
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• 1996

A chitosanase-producing bacteria was isolated on chitosan agar plate from soil samples. The strain was spore-forming gram positive bacteria, catalase positive, and rod shape. The strain was identified as Bacillus cereus. The strain did not need an inducer for the synthesis of chitosanase. Chitosanase from Bacillus sp. HW-002 was constitutive enzyme. The optimal medium for the production of the enzyme was composed of 0.5$\%$ sucrose and $1.5\%$ yeast extract-tryptone (1:1 w/w) mixture at pH 6.5. After Bacillus sp. HW-002 was cultivated at $32^{\circ}C$ for 32 h, maximal productivity was gained to be about 27, 200 U/l. Chitosanase from Bacillus sp. HW-002 was a mixed growth-linked metabolite.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.385-392
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• 1996

Bacillus stearotheymophilus, a potent xylanolytic bacterium isolated from soil, was tested for the strain's strategies of pentose utilization and the evidence of substrate preferences. The strain metabolized glucose, xylose, ribose, maltose, cellobiose, sucrose, arabinose and xylitol. The efficacy of the sugars as a carbon and energy source in this strain was of the order named above. The organism, however, could not grow on glycerol as a sole growth substrate. During cultivation on a mixture of glucose and xylose or arabinose, the major hydrolytic products of xylan, B. stearothermophilus displayed classical diauxic growth in which glucose was utilized during the first phase. On the other hand, the pentose utilization was prevented immediately upon addition of glucose. Cellobiose was preferred over xylose or arabinose. In contrast, maltose and pentose were co-utilized, and also no preference on between xylose and arabinose. Enzymatic studies indicated that B. stearothermophilus possessed constitutive hexokinase, a key enzyme of the glucose metabolic system. While, the production of $^{D}$-xylose isomerase, $^{D}$-xylulokinase and $^{D}$-arabinose isomerase essential for pentose phosphate pathway were induced by xylose, xylan, and xylitol but repressed by glucose. Taken together, the results suggested that the sequential utilization of B. stearothermophilus would be mediated by catabolite regulatory mechanisms such as catabolite inhibition or inducer exclusion.

• Microbiology and Biotechnology Letters
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• v.3 no.1
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• pp.1-6
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• 1975

The excellent strain $K_{52}$ for producing lipase was selected among 215 strains of Rhizopus sp. isolated from soil and other natural sources. The results investigated of microbiological characters and conditions for producing lipase Ivere summarized as follows： (1) Strain $K_{52}$ was similar to Rhizopus delemar in microbiological character. (2) The lipase activity was most vigorous after 48 hours in wheat bran culture, 96 hours in surface culture and 72 hours in shaking colure. (3) Surface culture was more suitable than in shaking culture for producing lipase. (4) In the case of wheat bran culture, producing of lipase was vigorous after 48 hours of culure period (3,800u/g) . (5) The optimum temperature for producing lipase was 3$0^{\circ}C$ both in wheat bran culture and in surfase culture.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.903-908
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• 2005

Inoculation of the carrier-based mixed bioinoculants af N-fixer (Azospirillum lipoferum strain Az204/Rhizobium strain BMBS P47) and phosphate-solubilizing bacterium (Bacillus megaterium var phosphaticum strain Pb 1) promoted growth and yield of pearl millet and blackgram under pot-culture conditions. The mixed inoculant of Az204 and Pb 1 enhanced germination, seedling vigor, plant height, and seed weight, and resulted in $6\%$ increase in grain yield of pearl millet. Likewise, the mixed inoculant of BMBS P47 and Pb1 increased growth, nodulation, and yield in blackgram. The rhizosphere soil enzyme activities, including nitrogenase, urease, and phosphatase, in both pearl millet and blackgram were significantly increased by the inoculation of the mixed inoculant, compared to that of the individual inoculants. The results clearly indicate the beneficial effect of co-culturing the N-fixer and P-solubilizer in inoculants production.

• The Korean Journal of Food And Nutrition
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• v.11 no.3
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• pp.340-346
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• 1998

The strain YSK-681 has been selected for antibiotic-producing strain against methicillin resistant Staphylococcus aureus(MRSA) form 1,000 strains of actinomycetes which had been isolated from soil. The strain YSK-681 has been identified on the point of morphological, cultural, physiological and chemical characteristics. Forty-one taxonomic unit characters were tested and the data were analysed numerically using the TAXON program. The isolate was classified into the major cluster 29 of Streptomyces and best-matched to Streptomyces lydicus. Therefore, it was concluded that the isolate was identified to be Streptomyces lydicus.

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.599-606
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• 2004

Gram-positive antagonistic bacilli were isolated from agricultural soils for possible use in biocontrol of plant pathogenic fungi, Fusarium oxysporum, Rhizoctonia solani, and/or Pythium ultimum. Among the 65 antagonistic Gram-positive soil isolates, 22 strains were identified as Bacillus species by 16S rDNA sequence analyses. Four strains, including DF14, especially exhibited multiple antagonistic properties against the three damping-off fungi. Genotypic properties of the Bacillus isolates were characterized by rapid molecular fingerprinting methods using repetitive extragenic palindromic-PCR (REP-PCR), ribosomal intergenic spacer-length polymorphisms (RIS-LP), 16S rDNA PCR-restriction fragment length polymorphisms (PCR-RFLP), and strain-specific PCR assays. The results indicated that the REP-PCR method was more valuable than the RIS-LP and 16S rDNA PCR-RFLP analyses as a rapid and reliable approach for bacilli typing and identification. The use of strain-specific primers designed based on 16S rDNA sequence comparisons enabled it to be possible to selectively detect a strain, DF14, which is being used as a biocontrol agent against damping-off fungi.