• Journal of Microbiology
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• v.39 no.4
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• pp.305-313
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• 2001

The spr D gene encoding Strptomyces griseus protease D(SGPD); a chymotrypsin-like proteae, was cloned from Strptomyces griseus IFO13350 and sequence. Most of the amino-acid sequence deduced from the nucleotide sequence is idential to that Strptomyces griseus IMRU3499 except that one amino acid has been deleted and Trp 369 has been substituted into Cys369 in the SGPD from S. griseus IFO13350 without affecting the protease activity. The spr D gene was overexpressed in Streptomyce liv-idans TK24 as a heterologous host. Various media with different compositions were also used to max-imize the productivity of SGPD inthe heterologous host. The SGPD productivity was best when the transformant S. lividans TK24 was cultivated in R2YE medium. The relative chymotrypsin activity of the culture broth measured with an artificial chromogenic substrate, N-scuccinyl-ala-ala-pro-phe-p-nitroanilide, was 16 units/ml. A high level of SGPD was also produced in YEME and SAAM medial but it was relatively lower that in R2YE medium and negligible amounts of SGPD were produced in GYE, GAE and Benedict media. The growth of S. lividans reacted the maximum level of cell mass at days 3 and 4 of the culture, but SGPD production started in the stationary phase of cell growth and kept increase in till the 10$^{th}$ day of culture in R2YE and YEME medium, but in GYE media the productivity reached maximum level at 8days of cultivation. The introduction of the spr D gene into S. lividans TK24 triggered biosyntheis of the pigmented antibiotic , actinorhodin, which implies some protease may paly a very improtant role in secondary-metabolite formation in sStreptomyces.

• Journal of Life Science
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• v.23 no.1
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• pp.102-109
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• 2013

To isolate GABA-producing microorganisms, 1,500 strains were isolated from different Chungkookjang samples and screened. From these strains, 20 were selected for further analyses based on a protease and slime-producing activity test. The MC 31 strain showed the highest GABA concentration in Chungkookjang and was used in this study. MC 31 was identified as Bacillus subtilis by an API 50CHB kit and 16S rDNA sequences analysis and named as B. subtilis MC 31. B. subtilis MC 31 showed exponential growth up to 12 hours at $37^{\circ}C$ in LB broth, and it reached a stationary phase after 24 to 36 hours of incubation. B. subtilis MC 31 showed maximum GABA content at 72 hours after incubation at $40^{\circ}C$.

• Steel and Composite Structures
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• v.19 no.3
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• pp.569-583
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• 2015

Recent years, explosive welding structures have been widely used in many engineering fields. The bonding state detection of explosive welding structures is significant to prevent unscheduled failures and even catastrophic accidents. However, this task still faces challenges due to the complexity of the bonding interface. In this paper, a new method called dual-tree complex wavelet transform based permutation entropy (DTCWT-PE) is proposed to detect bonding state of such structures. Benefiting from the complex analytical wavelet function, the dual-tree complex wavelet transform (DTCWT) has better shift invariance and reduced spectral aliasing compared with the traditional wavelet transform. All those characters are good for characterizing the vibration response signals. Furthermore, as a statistical measure, permutation entropy (PE) quantifies the complexity of non-stationary signals through phase space reconstruction, and thus it can be used as a viable tool to detect the change of bonding state. In order to more accurate identification and detection of bonding state, PE values derived from DTCWT coefficients are proposed to extract the state information from the vibration response signal of explosive welding structure, and then the extracted PE values serve as input vectors of support vector machine (SVM) to identify the bonding state of the structure. The experiments on bonding state detection of explosive welding pipes are presented to illustrate the feasibility and effectiveness of the proposed method.

• Food Science and Preservation
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• v.9 no.2
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• pp.200-204
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• 2002

This study was carried out to investigate the effect of safflower powder on the characteristics of kimchi. Quality indexes were pH, titratable acidity, reducing sugar content, microbial counts, and sensory evaluation. Safflower powder enhanced the decrease in pH and increase in titratable acidity during fermentation at l0$^{\circ}C$, and the changes were more conspicuous until 15 days. Stabilized levels in pH was attained, but steady increase in titratable acidity was shown after that time. Microbial loads of total and lactic acid bacteria showed a faster stationary phase for kimchi samples with safflower powder than control. Control was better scores in sensory evaluation, but there were no significant differences in aroma and taste except sample with 3% safflower powder.

• Microbiology and Biotechnology Letters
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• v.5 no.1
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• pp.24-28
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• 1977

For the production of microbial cells from cellulosie materials by cellulore-assimilating bacteria, Cellulomonas flavigena GFB 24-1, isolated by authors, utilization of this organism on some microbiological properties was investigated. The results of these studies were summarized at follows; 1. When the organism was incubated in the growth medium at pH 7.0 for 50 hours, its growth was the most effective and the level of excreted total protein in the menstruum increased continuously during the stationary phase of cell growth. 2. The optimal enzyme activity was observed in the pH region of 5 to 7 and culture period of 40 to 50 hours. 3. The microbial degestibility of cellulosic wastes such as sawdust, rice hull, rice straw, peanut hull and used newspaper was less than 30％, whereas that of cellulose powder was 47.1％ and rice straw was digested 77％ by NaOH treatment. 4. Bacterial cells incubated in the growth medium were increased up to 8％ of sustrate concentration and showed a decrease on further concentration. 5. The production of microbial cells from NaOH treated rice straw was obtained 10.6mg/ml of culture medium.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.488-497
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• 1999

Probing Streptomyces albus ATCC 21838 chromosomal DNA with a proline tRNA sequence resulted in an isolation of a putative integrating element in the 6.4-kb EcoRI fragment. It was found that Streptomyces lividans TK-24 transformed with a cloned DNA fragment on a multicopy plasmid, produced a higher level of spore pigment and mycelial red pigment on a regeneration agar. Furthermore, the transformant S. lividans TK-24 produced a markedly increased level of undecylprodigiosin in a broth culture. A nucleotide sequence analysis of the cloned region revealed several open reading frames homologous to the integrases of integrating plasmids or temperate bacteriophages, signal-transducing regulatory proteins with a conserved ATP-binding domain, oxidoreductases ($\beta$-ketoacyl reductase), and an AraC-like transcriptional regulator. To examine the effect on antibiotic production, each coding region was overexpressed separately from the other genes in the region in S. lividans TK-24 with; pJHS3044 for the expression of the signal-transducing regulatory protein homologue, pJHS3045 for the homologue of oxidoreductase, and pJHS3051 for the homologue of the AraC-like transcriptional regulator. Phenotypic studies of S. lividans TK-24 strains harboring plasmids for the overexpression of individual genes suggested the following effects of the genes on antibiotic production: The oxidoreductase homologue stimulated the production of actinorhodin and undecylprodigiosin, which was influenced by the culture conditions; the homologue of the AraC-like transcriptional regulator was the most effective factor in antibiotic production within all the culture conditions tested; the signal-transducing regulatory protein homologue repressed the effect due to the homologue of the AraC-like transcriptional regulator, however, the antibiotic production was derepressed upon entering the stationary phase.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.252-258
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• 2011

A bacterial strain capable of hydrolyzing xylan and locust bean gum (LBG) was isolated from farm soil by enrichment culture using mixture of palm kernel meal (PKM) and wheat bran as carbon source. Nucleotide sequence of 16S rDNA amplified from the isolate YB-1107 showed high similarity with those of genus Cellulosimicrobium strains. Xylanase productivity was increased when the Cellulosimicrobium sp. YB-1107 was grown in the presence of wheat bran or oat spelt xylan, while mannanase productivity was increased drastically when grown in the presence of PKM or LBG. Particularly, maximum mannanase and xylanase activities were obtained in the culture filtrate of media containing 0.7% PKM or 1% wheat bran, respectively. Both enzyme activities were produced at stationary growth phase. Mannanase from the culture filtrate showed the highest activity at $55^{\circ}C$ and pH 6.5. Xylanase activity was optimal at $65^{\circ}C$ and pH 5.5. The predominant products resulting from the mannanase or xylanase hydrolysis were oligosaccharides for LBG or xylan, respectively. In addition, the enzymes could hydrolyze wheat bran and rice bran into oligosaccharides.

• Korean Journal of Microbiology
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• v.22 no.1
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• pp.49-56
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• 1984

Formation and regeneration of protoplasts by Novozym 234 from Kluyveromyces fragilis N100 and Candida pseudotropicalis CBS607 were studied. This enzyme was more effective on cells grown at exponential phase than those at stationary one to convert intact cells into protoplasts. As osmotic stabilizer, ammonium sulphate was suitable for not only protoplast formation but also regeneration in K. fragilis as well as in C. pseudotropicalis. Optimal enzyme concentration was 3mg per ml in K. fragilis and 1~3mg per ml in C. pseudotropicalis, respectively. After the exposure of K. fragilis cells to 3mg per ml of enzyme for 3hr at 30$^{\circ}C$ , approximately 95% of protoplast formation of all observed cells was obgained, while about 100% from C. pseudotropicalis under the same condition was produced. The regeneration frequency of protoplasts by this enzyme was much lower than that by snail enzyme(Glusulase) although Novozym 234 converted cells from above two species into protoplasts free of cell debris effectively, compared with Glusulase. Novozym 234 appears to be suitable for subcellular fractionation to obtain nuclei or other organelles rather than protoplast regeneration.

• Journal of Environmental Science International
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• v.24 no.4
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• pp.541-547
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• 2015

Formation of disinfection by-products (DBPs) including trihalomethans (THMs) and haloacetic acids (HAAs) from chlorination of six different species (Chlorella vulgaris, Scenedesmus sp., Anabaena cylindrical, Microcystis aeruginosa, Asterionella formosa and Aulacoseira sp.) of algal extracellular organic matter (EOM). The EOM characteristics evaluation of six algal species reaching at the stationary phase in the growth curve showed most of its SUVA254 showed below 1 and this means hydrophilic organic matter is much higher than hydrophobic organic matter. Chloroform formation potential (CFFP), dichloroacetic acid formation potential (DCAAFP) and trichloroacetic acid formation potential (TCAAFP) were mainly composed of THMFP and HAAFP in the EOM of various algal species. In the case of THMFP/DOC and HAAFP/DOC values, EOM of blue-green algae has appeared highest and EOM of green algae and diatom in order. THMFP/DOC was higher than HAAFP/DOC in EOM of blue-green algae. In comparison of formation potential by unit DOC composed of HAAFP in algal species EOM, DCAAFP/DOC was 1.5 times to 7.5 time higher than TCAAFP/DOC in the EOM of blue-green algae, while DCAAFP/DOC was found to be relatively high compared to TCAAFP/DOC in the EOM of green algae and diatom.

• Journal of the Korean earth science society
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• v.30 no.6
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• pp.692-698
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• 2009

Wavelet transform has been widely used in terms that it may overcome the shortcoming of conventional Fourier transform. Fourier transform has its difficulty to explain how the transformed domain, frequency, is related with time. Traditional semblance technique in Fourier transform was devised to compare two time series on the basis of their phase as a function of frequency. But this method is known not to work well for the non-stationary signal. In this study, we present two applications of the wavelet-based semblance method to geophysical data. Firstly, we show filtered geomagnetic signal remained with components of high correlation to each observatory. Secondly, highly correlated residual signal of gravity and magnetic survey data, which are also filtered by this semblance method, is present.