• Journal of Microbiology and Biotechnology
• /
• v.20 no.3
• /
• pp.602-608
• /
• 2010

An atrazine-degrading bacterium, strain KU001, was obtained from a sugarcane field at the Cane and Sugar Research and Development Center at the Kasetsart University, Kamphaeng Saen Campus, Thailand. Strain KU001 had a rod-to-coccus morphological cycle during growth. Biolog carbon source analysis indicated that the isolated bacterium was Arthrobacter histidinolovorans. Sequence analysis of the PCR product indicated that the 16S rRNA gene in strain KU001 was 99% identical to the same region in Arthrobacter sp. The atrazine degradation pathway in strain KU001 consisted of the catabolic genes trzN, atzB, and atzC. Strain KU001 was able to use atrazine as a sole nitrogen source for growth, and surprisingly, atrazine degradation was not inhibited in cells grown on ammonium, nitrate, or urea, as compared with cells cultivated on growth-limiting nitrogen sources. During the atrazine degradation process, the supplementation of nitrate completely inhibited atrazine degradation activity in strain KU001, whereas ammonium and urea had no effect on atrazine degradation activity. The addition of strain KU001 to sterile or nonsterile soils resulted in the disappearance of atrazine at a rate that was 4- to 5-fold more than that achieved by the indigenous microbial community. The addition of citrate to soils resulted in enhanced atrazine degradation, where 80% of atrazine disappeared within one day following nutrient supplementation.

• Journal of Species Research
• /
• v.8 no.2
• /
• pp.176-190
• /
• 2019

A total of 38 bacterial strains within the classes Bacilli and Deinococci were isolated from various sources in Korea. Samples were collected from animal intestine, urine, soil, tidal flat mud, and kimchi. In the sequence comparison and phylogenetic analysis of 16S rRNA sequences, the 38 isolates were assigned to the classes Bacilli and Deinococci with sequence similarities more than 98.7%. Twenty-four strains and 13 strains were classified the order Bacillales and Lactobacillales in the class Bacilli, respectively. In the order Bacillales, there were nine species in the genus Bacillus, seven species in the genus Paenibacillus, and the remaining eight species in the genera Domibacillus, Halobacillus, Virgibacillus, Lysinibacillus, Paenisporosarcina, Planococcus, Savagea, and Staphylococcus. In the order Lactobacillales, there were four species in the genus Lactobacillus, three species in the genus Leuconostoc, three species in the genus Lactococcus, and the remaining three species in the genera Aerococcus, Enterococcus, and Streptococcus. One species was related to the genus Deinococcus of the order Deinococcales. Most of the isolated strains were Gram-stain-positive, but some were Gram-stain-variable or Gram-stain-negative. Cells were rod or cocci-shaped. Based on the results of 16S rRNA analysis, we report 38 strains as previously unrecorded species to Korea, and the basic characteristics of strains are described herein.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.5
• /
• pp.338-343
• /
• 2015

Dye sensitized solar cells (DSSCs), which is one of the contending renewable energy sources, have the problem of low efficiency. To improve the efficiency, the fast electron transport and long electron lifetime are required. In this study, one-dimensional sodium hexatitanate, which is expected to have an advantageous structure for electron transports, was synthesized and the feasibility of the material on DSSC was tested. Its physical properties were characterized by the SEM, XRD, and BET method. The dye adsorption and solar cell properties were also characterized. In addition to the expectation of fast electron transport, sodium hexatitanate showed longer electron lifetime: This means sodium hexatitanate can improve the DSSC efficiency. However, it showed low current and voltage because of the low surface area leading to the low amount of dye adsorbed. Therefore, it should be mixed with titanium oxide with high surface area for the optimal performance.

• Journal of Environmental Science International
• /
• v.17 no.4
• /
• pp.469-477
• /
• 2008

The aerobic photosynthetic bacterium, which produces bacterial carotenoids was isolated and identified from coastal marine environments. This bacterium was identified by 16S rDNA sequencing and designated as Erythrobacter longus SY-46. E. longus SY-46 was Gram negative and rod shape, and the optimal culture conditions were $25^{\circ}C$, pH 7.0, and 3.0% NaCl concentration, respectively. The carbon and nitrogen sources required for the optimal growth were lactose and tryptone, respectively. Fatty acid compositions of E. longus SY-46 were $C_{18:1}$(78.32%), v-linolenic acid($C_{18:3n9.12.15c}:3.83%$), margaric acid($C_{17:0}$: 3.38%), palmitic acid($C_{16:0}$: 3.07%), and docosahexaenoic acid($C_{22:6n3}$: 2.21%). In addition, E. longus SY-46 showed the characteristic absorption peaks of bacterial carotenoids(in the region of 450 to 480 nm) and bacteriochlorophyll(770 to 772 nm). Major carotenoids of E. longus SY-46 were polyhydroxylated xanthophylls such as fucoxanthin and zeaxanthin.

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.5
• /
• pp.72-78
• /
• 2009

We propose the separation algorithm to simultaneously measure two-dimensional refractive index distribution and thickness profile of transparent samples using three wavelengths. The optical system was based on the Mach-zehnder interferometer with LD (Laser Diode)-based multi-wavelength sources. A LCR (Liquid Crystal Retarder) was used to obtain interference images at four phase states and then the optical phase of the object is calculated by four-bucket algorithm. Experimental results with a glass rod are provided at the different wavelengths of 635nm, 660nm and 675nm. The refractive indices of the sample are distributed with accuracy of less than 0.0005 and the thickness profile of sample was cylindrical type. This result demonstrates that it is possible to separate refractive index distribution and thickness profile of samples in two dimensions using the proposed algorithm.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 1999.11b
• /
• pp.172-177
• /
• 1999

Effect of fiber treatment with cellulase (Liftase A40), and with two refining methods (Valley beating and impact refining) on wood fiber and handsheet properties were investigated at three refining levels (300, 400, and 500ml) for two furnishes (NBKP and LBKP). Part of the treated furnishes were classified by 150 mesh screen into fine-free fiber, and fines. Fiber length analysis, WRV, zero-span strength, and other handsheet mechanical properties were compared. The study showed that Liftase A40 lowered the zero-span and the folding endurance of both furnishes (NBKP much more and LBKP much less). Pretreatment with Liftase A 40 followed by refining significantly lowered the fiber length and refining energy to reach to the target freeness. Impact refining, which is done by hitting the fibers vertically with rod at 20% solid content, kept the fiber length increased WRV, and improved handsheet mechanical properties much more than valley beating. Properties of fines from different sources were compared in detail in the study.

• Korean Journal of Microbiology
• /
• v.28 no.4
• /
• pp.331-336
• /
• 1990

Annual distribution of hiterotrophic marine bacteria and seasonal characteristics were investigated in the intertidal waters and sediments in the vicinity of Kunsan of Yellow Sea, Korea. Annual distribution of heterotrophic marine bacteria ranged from $ 7.5*10^{2}$ to $1.1*10^{5}$ c.f.u./ml in water and from $1.6*10 ^{4}$ to $4.8*10^{6}$ c.f.u.per g dry sediments. As for the morphological distribution measured by epifluorescence microscopy, rod-form bacteria were distributed more than 74% of total observed bacteria during surveying periods. Average biovolume of sampled bacteria ranged from $3.19\;+-\;0.59*10^{-2}$ to $6.19\;+-\;0.76*10^{-2}$ $\mu$$m^{3}$ for coccus-form bacteria. Isolated bacteria showed various utilization of carbon sources such as glucose, maltose, lactose, xylose and arabinose, and showed tolerance at various range of salinity. It was isolated 82 genus in seawater and 114 genus in sediments. Dominant genera were Pseudomonas, Vibrio, Flavobacterium and Acinetobacter in seawater, and Pseudomonas, Acinetobacter, Vibrio, and Mycobacterium in sediments.

• Journal of Applied Biological Chemistry
• /
• v.61 no.3
• /
• pp.233-238
• /
• 2018

Chitinases are glycosyl hydrolases which cleave the ${\beta}$-1,4 linkage of chitin into oligo or monomers of N-acetylglucosamine. These bacterial enzymes have been used for a wide range of applications in the food and pharmaceutical industries. In this study, we isolated two potential chitinolytic strains, BAO-01 and BAO-02, from salt-fermented shrimp, which were shown to belong to the genus Salinivibrio through genetic characterization using 16S rRNA. These isolates were gram-positive, rod-shaped, and non-spore forming. BAO-01 showed greater growth and chitinase activity than BAO-02 after the incubation at $37^{\circ}C$ for 4 days. Both strains grew on a wide range of carbon and nitrogen sources, pH values, temperatures, and salt levels. However, they showed minor biochemical differences. In addition, their antimicrobial activities against foodborne pathogens and antibiotic susceptibilities were evaluated. These Salinivibrio spp. did not show bioamine production, hemolytic activity, and mucin degradation. Therefore, the in vitro screening results suggested that these bacteria could be widely used as new candidates for chitin hydrolyzation and seafood fermentation.

• Korean Journal of Microbiology
• /
• v.27 no.3
• /
• pp.297-303
• /
• 1989

Attempts to isolate the naturally occurring ultra-violet resistant bacteria from environmental sources were made. The isolates, designated No.29, 100, and 107, among numbers of bacterial isolates revealed a remarkable resistance to UV ray, whose degree of resistance in dose/response kinetics was comparable to that of an endospore-former, Bacillus subtilis. In a range of 100-300 $Jm^{-2}$/min of UV irradiation, the isolates exhibited 500-1000 fold resistance compated with E. coli. The isolated appeared to possiss cell-bound pigment of organge or crimson-red. The isolate 29 is spherical in pairs or tetrads, whereas the isolates 100 and 107 are rod. All are Gram-gositive bacteria and seemed to be non-endospore-bearer. A number of biochemical studies pursued on the isolates suggested that they are quite different to each other. Electron microscopic examination and the physiological characters of the isolate 29 suggested that this UV resistant spherical bacterium might be one species of Deinococcus, probably Deinococus radiophilus. Since there is no documents on UV resistant, Gram-positive, non-sporeformer bacillus so far, the isolates 100 and 107 might be turned out as new kinds of UV resistant bacteria occurring in nature by further investigation.

• Korean Journal of Agricultural Science
• /
• v.19 no.1
• /
• pp.28-32
• /
• 1992

Phototrophic bacteria T-20 investigated in the present report was isolated from Thailand oil, Cells of the bacterium were rod-shaped. measured $0.6{\sim}0.7{\mu}m$ wide, and $2.3{\mu}m$ long. A color of cell suspension was red, and the long wavelength absorption maxima of the bacteriochlorophyll measured in 870nm. Substrates utilized as carbon sources: citrate, aspirate, glutamate, and fructose: unique for this strain is the liquefaction of gelatine, Ubiquinone Q-8 was also found. Rhodocyclus gelatinosus, which was reported in Bergey's Manual of Systematics Bacteriology, was corresponded to T-20.