• KSBB Journal
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• 제25권3호
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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%.

• 생명과학회지
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• 제12권6호
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• pp.759-764
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• 2002

해수에서 분리한 Burkholderia sp. IS-203으로부터 면역 증강물질을 생산하기 위한 최적조건을 검토한 결과는 다음과 같다. 면역증강물질을 생산하는 최적 배양조건은 인공해수에 1% glucose와 1% yeast extract 였으며, 최적 NaCl 요구성은 3%로 전형적인 해양세균의 특징을 보여주는 것으로 생각되어진다. 그리고 최적 배양조건으로 최적 초기 pH는 8.0, 최적 온도는 $30^{\circ}C$였으며, 산소를 요구하는 호기성균이었다. 면역증강물질을 생산하기 위한 배양조건은$35^{\circ}C$, pH 6.0이었으며, 최적생육 배지는 1.5% soluble starch, 1% tryptone, 0.5% yeast extract로 조성하여 500 $m\ell$의 삼각플라스크에 $50m\ell$씩 분주하여 진탕배양하였다. 이와 같은 최적조건에서 항생물질은 정지기부터 생산되는 비증식연관형으로서 포자형성이후부터 생산되었다.

• Journal of Microbiology and Biotechnology
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• 제6권1호
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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.

• Mycobiology
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• 제38권3호
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• pp.171-175
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• 2010

Metacordyceps yongmunensis is a newly reported species from Korea, which is very similar to Cordyceps species in morphological characters. It grows on large lepidopteran pupa, and numerous white stromata grow on a single host. Mycelial growth characteristics of M. yongmunensis isolates were studied in different media and at different temperatures. Also, different carbon sources, nitrogen sources, and mineral salts were tested for mycelial growth of M. yongmunensis. Schizophyllum (mushroom) genetics complete medium plus yeast extract, Schizophyllum (mushroom) genetics minimal medium, and Martin's peptone dextrose agar produced longer colony diameters and more compact mycelial density than other media. The optimum temperature for mycelial growth was $25^{\circ}C$. Carbon sources such as sucrose, soluble starch, dextrose, glucose, dextrin, maltose, and fructose showed better mycelial growth, whereas peptone, yeast extract and tryptone resulted in the best mycelial growth of all of the nitrogen sources tested. All of the mineral salts tested showed similar growth as the control, except $K_2HPO_4$ which showed longer colony diameter and more compact mycelial density. The compact colonies were white and cottony with a greenish margin. The results showed that M. yongmunensis is an easy fungus to growas it grew from 30 to more than 50 mm in 2 wk.

• 한국환경농학회지
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• 제28권4호
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• pp.447-452
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• 2009

A bacterium, which was named to be Bacillus cereus A-139, secreting auxin was isolated from the east coast sand dunes in Korea. The secretion of auxin was confirmed by HPLC. When cultured in LB broth, Bacillus cereus A-139 produced $16.12\;{\mu}$g/mL auxin after 8 days in LB broth. Bacillus cereus A-139 produced $49\;{\mu}$g/mL auxin and $162.6\;{\mu}$g/mL by the addition of 2% tryptone and 0.1% tryptophan, respectively. The root growth of Arabidopsis thaliana was retarded by Bacillus cereus A-139 culture broth up to 57% but the formation of lateral roots was increased up to almost twice after 4 days incubation. Also the formation of lateral roots of mung bean was increased up to 57% after 10 days incubation.

• Journal of Microbiology and Biotechnology
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• 제5권2호
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• pp.80-86
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• 1995

The bacterial strain WC-17 able to produce chitinase was isolated from soil using an enrichment technique. The isolated strain was identified as Acinetobacter sp. judging by their morphological and physiological characterisitics. The optimal culture conditions for the production of chitinase of Acinetobacter sp. WC -17 are 1.5% colloidal chitin and 1 % tryptone at $30^{\circ}C$ with pH 6.5. Since the enzyme was rapidly produced in a culture supplied with chitin, glucose, or N-acetylglucosamine but not with other polymers and monosaccharide, the enzyme was considered to be an inducible enzyme. Notably N- acetylglucosamine and glucose were found to be effective inducers at low concentrations but repressors at excessive concentrations. The cultural supernatant of Acinetobacter sp. WC-17 inhibited the growth of phytopathogenic fungi such as P.oryzae, R.solani, and F.solani. Among the phytopathogenic fungi tested, P.oryzae was the most sensitive. The conventional agar plate (PDA containing 1 % colloidal chitin) method also produced the same result.

• Journal of Microbiology and Biotechnology
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• 제4권1호
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• pp.36-40
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• 1994

A water sample was taken from a black smoker chimney of a deep-sea hydrothermal vent by using an unmanned submersible "Dolphin 3K". The temperature of the hydrothermal fluid from the black smoker was $276^{\circ}C$. After isolation by repeated serial dilutions, An extremely thermophilic bacterial strain was selected. The strain designated as DT1331, was an anaerobic, non-motile, coccoid shaped bacterium with about 0.5 to $1.0\;\mu\textrm{m}$ in diameter. The strain DT1331 could grow up to $93^{\circ}C$, but the optimum temperature of this strain was $80^{\circ}C$. The growth occurred in the pH range of 4.5 to 8.5 and the optimum pH was 6.0. The strain DT1331 required 1% to 5% NaCl for growth and cell lysis was observed below 1% NaCl concentration. The bacterium could grow on polypeptides such as tryptone, peptone, soytone and on proteins such as casein or gelatin. However, no growth was observed on single amino acids, sugar and organic acids. Hydrogen gas was detected slightly during growth. This bacterium obligately required elemental sulfur and hydrogen sulfide gas was produced during growth.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1856-1861
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• 2006

A Bacillus sp. A-6 strain that produced xylanase was isolated from rice bran. The optimal temperature and pH for xylanase activity of the culture supernatant of Bacillus sp. A-6 were 40$^{\circ}C$ and pH 7, respectively. The optimal temperature and pH for xylanase production in the xylan medium were 30$^{\circ}C$ and pH 9, respectively. The optimal concentrations of oat spelt xylan and peptone for xylanase production were 0.5% and 1.5%, respectively. The best nitrogen sources for xylanase production was beef extract, but xylanase production was also supported comparably by tryptone and peptone. The bacterial growth in the optimal xylan medium reached stationary growth phase after 12 h of incubation. The xylanase production in the culture supernatant increased dramatically during the initial 12 h exponential growth phase and then remained constant at 23.8-24.5 unit/ml during the stationary growth phase. The pH of the culture medium decreased from 8.8 to 6.7 during the exponential growth phase and subsequently increased to 8.1 during the stationary growth phase. Rice bran, sorghum bran, and wheat bran as well as oat spelt xylan induced xylanase production. The xylanase production was repressed when glucose was added to the xylan-containing medium.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.449-456
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• 2002

The objective of this study was to optimize medium composition of initial pH, tryptone, glucose, yeast extract, and mineral mixture for production of bacteriocin by Lactobacillus acidophilus ATCC 4356, using response surface methodology. A response surface approach including new statistical and plotting methods was employed for design and analysis of the experiment. An interiorly augmented central composite design was used as an experimental design. A normal-distribution log-link generalized linear model based on a subset fourth-order polynomial ($R^2$=0.94, Mean Error Deviance=0.0065) was used as an analysis model. This model was statistically superior to the full second-order polynomial-based generalized linear model ($R^2$=0.80, Mean Error Deviance=0.0140). Nonlinear programming determined the optimum composition of the medium as initial pH 6.35, typtone $1.21\%$, glucose $0.9\%$, yeast extract $0.65\%$, and mineral mixture $1.17\%$. A validation experiment confirmed that the optimized medium was comparable to the MRS medium in bacteriocin production, having the advantage of economy and practicality.

• 한국미생물·생명공학회지
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• 제23권6호
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• pp.695-701
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• 1995

An alkaline lipase producing bacteria was isolated from soil and identified as Serratia liquefaciens AL-11. from the results of analysis of its morphological, biochemical and physiological properties. This strain showed the highest productivity of alkaline lipase when grown at pH 9.0 and 30$\circ$C for 42 hours in the medium of 1% peptone, 0.5% tryptone, 0.9% yeast extract, 1% starch, 1% tween 80, 0.05% CaCl$_{2}$ and 0.05% NaCl. The enzyme was purified by ammonium sulfate treatment, Sephadex G-100 gel filtration and DEAE-Sephadex A-50 column chromatography. The specific activity of the purified enzyme was 27 unit/mg protein and the yield of enzyme activity was 61.3%. The homogeneity of the purified enzyme was verified by polyacrylamide gel disc electrophoresis. Molecular weight of the purified enzyme was estimated about 53,000 by sodium dodecyl sulfate- polyacrylamide gel electrophoresis. This enzyme is composed of 17 amino acids of which glycine, proline and glutamic acid were three miajor acids.