• KSBB Journal
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• v.23 no.1
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• pp.23-30
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• 2008

An extracellular pigment production of three Phellinus sp. (Phellinus 421, P. linteus and P. hartigil) through submerged cultivation was investigated. The maximum brown pigment from culture broth was obtained from the precipitate by addition of 10% 1M HCI solution. This precipitate showed absorption characteristics with ${\lambda}_{max}$ of 360nm. The maximum production of extracellular pigment obtained at optimum medium and culture condition was 3.54 ($A_{360}$). The precipitate was fractionated by Sephadex G-75 gel chromatography, and the isolated brown pigment contained a large amount of polyphenol and the small amounts of sugar and protein. The brown pigment fraction was stable in temperature range of $30{\sim}60^{\circ}C$, pH range of $4{\sim}6$, sugar addition ranges of $1{\sim}5%$ and salt addition concentration of 3 molarity. Antioxidative activity of the brown pigment by TBA method was better than that of vitamin E (${\alpha}$-tocopherol).

• Korean Journal of Microbiology
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• v.38 no.1
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• pp.50-53
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• 2002

The optimum temperature and pH for mycelial growth of B. bassiana DGUM 34001 were $24^{\circ}C$ and pH 7.0, respectively. Among the complex media used, mushroom complex medium (MCM) was the most favorable for mycelial growth. When Czapek-Dox medium was used as a minimal medium, glucose was an excellent source for carbon and energy. Soytone and sodium phosphate were favorable constituent for culture medium as a source of organic nitrogen and phosphorus, respectively. When the fungus was grown in MCM broth, the specific activity of extracellular enzyme of ${\alpha}$-amylase, lipase, chitinase, CMCase and pretease were 297.0, 0.058, 0.33, 0.21 and 22.8 units/mg protein, respectively. When various sources of organic nitrogen and chitin were supplemented to determine the production of enzymes, casein and soluble chitosan enhanced the production of extracellular protease and chitinase.

• Journal of Microbiology
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• v.37 no.1
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• pp.1-9
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• 1999

The Biolog redox technology was carried out for evaluation of acidification effect on microbial communities at each stage of pH gradient microcosm. While the number of heterotrophic bacterial population and activities of extracellular enzyme decreased as the pH decreased, the number of total bacteria in the microcosm was not affected. The average color development of sample at each pH-gradient showed a sigmoidal curve, and at higher pH, more overall color development appeared in Biolog plates. Average color development value in Biolog plates was stabilized at 50 hours as an optimum incubation time. The color production in the Biolog plates was caused by cell density at above pH 5.0, but by cell activity below pH 4.0. Principal component analysis of color responses revealed distinctive patterns among the pH-gradient microcosm samples.

• Applied Biological Chemistry
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• v.44 no.4
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• pp.246-250
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• 2001

In order to produce alkaline protease, psychrotrophic Bacterium which have high enzyme activity, was isolated by using enrichment culture from soil samples and identified as genus Bacillus sp. The optimal pH and temperature for the enzyme activity were pH 6 and $40^{\circ}C$. The temperature range of high enzyme activity was $20{\sim}40^{\circ}C$. The optimal initial pH of culture condition for enzyme was pH 6. The most favorable carbon and nitrogen sources for the production of protease by Bacillus sp. WRD-2 were 3% maltose and 4% yeast extract, respectively.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.188-196
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• 2014

Extracellular production of recombinant human bone morphogenetic protein-7 (rhBMP-7) was carried out through the fermentation of Bacillus subtilis. Three significant fermentation conditions and medium components were selected and optimized to enhance the rhBMP-7 production by using the response surface methodology (RSM). The optimum values of the three variables for the maximum extracellular production of rhBMP-7 were found to be 2.93 g/l starch, 5.18 g/l lactose, and a fermentation time of 34.57 h. The statistical optimization model was validated with a few fermentations of B. subtilis in shake flasks under optimized and unoptimized conditions. A 3-L jar fermenter using the shake-flask optimized conditions resulted in a higher production (413 pg/ml of culture medium) of rhBMP-7 than in a shake flask (289.1 pg/ml), which could be attributed to the pH being controlled at 6.0 and constant agitation of 400 rpm with aeration of 1 vvm.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.5
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• pp.359-362
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• 2001

The production of an extracellular polysaccharide, EPS-R, from the marine bacterium Hahella chejuensis was investigated at various aeration rates in a batch culture. Higher aeration rate resulted in enhanced EPS production and increased the viscosity of the culture broth. At an aeration rate of 1.5 vvm, EPS-R (12.2 g/L) was obtained with a yield (Y$\_$p/s) of 0.6 from the STN medium after 72 h of cultivation. The H. chejuensis cells changed rod morphology to a short-rod form in the stationary growth phase.

• Microbiology and Biotechnology Letters
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• v.21 no.3
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• pp.239-246
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• 1993

Producing an extracellular alkaline lipase, this isolate JM123 was identified as a Pseudomonas aeruginosa strain from the results of the analyses of its morphological, biochemical and physiological properties. This strain showed the highest productivity of alkaline lipase when grown at pH 9.0 and 30C for 13-20 hours in the medium of 2% starch, 1% soytone, 0.5% peptone and 1% MgSO4.7H2O. However, this enzyme was greatly repressed when grown in the glucose containing medium. The culture broth was fractionated by the order of the ammonium sulfate precipitation, Sephadex G-200 gel filtration, DEAE-cellulose column chromatography, and Sephadex G-150 gel filtration.

• Korean Journal of Environmental Biology
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• v.20 no.1
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• pp.85-90
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• 2002

In an artificial pH-gradient batch culture system, the author analyzed the effects of acidification on the species composition of heterotrophic bacteria. As the result of this study, it was found that the numbers of total bacteria were not affected by acidification and that the population size of heterotrophic bacteria decreased as pH became lower. The heterotrophic bacteria isolated from all of the pH gradient were 12 genera and 22 species, and among them, gram negative and gram positive bacteria were 04% and 30%, respectively. As pH decreased, the distribution rate of gram negative bacteria increased while that of gram positive bacteria decreased. Regarding to distribution rate of genuses in each pH gradient, 13 genuses appeared at pH 7 while only 5 genuses appeared at pH 3, which means that the diversity of genera decrease as pH decreased. The activities of extracellular enzyme showed the ranges of $0.008-0.292\;\mu{M}\ell^{-1}\;hr^{-1}$ in bioreactor system. The enzymatic activities decreased rapidly below pH 5 and then sustained 5-38% at the lower pH values.

• Korean Journal of Microbiology
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• v.25 no.3
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• pp.221-228
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• 1987

The extracellular adenine deaminase from Nocardioides sp. J-275L was purified by the following techniques: ammonium sulfate fractionation, DEAE-Cellulose, DEAE-Sephadex A-50 column chromatography, and Sephacryl S-200 superfine gel filtration. The enzyme was partially purified about 3889.5-fold with about 5.2% yield by these procedures. The molecular weight of the enzyme was 39,000 by a calibrated Sephacryl S-200 superfine column chromatography. The enzyme was stable at pH 7.5 and up to $40^{\circ}C$. Glycerol was effective on the stabilization of the enzyme during storage. The optimum pH and temperature of the enzyme were around pH 7.5 and $40^{\circ}C$, respectively. The apparent Michaelis constant Km of the enzyme for adenine was $7.4\times 10^{-5}$M. The purine analogues, 6-chloropurine, 2,6-diaminopurine, 6-bromopurine, 4-aminopyrazolo [3.4-d]pyrimidine, and 8-azaadenine were substrates for the enzyme. 6-Dimethylaminopurine was a competitive inhibitor of the enzyme. The enzyme was inhibited by 1mM of $Cu^{2+}, Fe^{3+}, Pb^{2+}, Hg^{2+}$, and $Ag^{+}$, and 1mM of $\alpha$,$\alpha$'-dipyridyl, pentachlorophenol, and pCMB.

• Journal of Microbiology
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• v.37 no.4
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• pp.213-217
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• 1999

An extracellular endopeptidase from Bacillus cereus SH-7 was purified to homogeneity. The protease was most active at pH 8 and $40{\circ}C$, respectively. The molecular mass of the protease was 40 kDa on SDS-PAGE, and 120 kDa by gel filtration, suggesting that the native enzyme is composed of three homogeneous subunits. The $K_m\;and\;V_{max}$ values of the protease for N-succinyl-$(Ala)_2$-Pro-Phe-p-nitroanilide were 11.11 mM and 170 nmol/mg of protein/min, respectively. The protease was also identified as a metalloprotease. The bioactivity of the SH-7 protease will need further study in the future.