• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.510-518
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• 2021

Bacteriophages are considered excellent sensing elements for platforms detecting bacteria. However, their lytic cycle has restricted their efficacy. Here, we used the minor coat protein pIII domain (N1N2) of phage CTXφ to construct a novel surface plasmon resonance (SPR) biosensor that could detect Vibrio cholerae. N1N2 harboring the domains required for phage adsorption and entry was obtained from Escherichia coli using recombinant protein expression and purification. SDS-PAGE revealed an approximate size of 30 kDa for N1N2. Dot blot and transmission electron microscopy analyses revealed that the protein bound to the host V. cholerae but not to non-host E. coli K-12 cells. Next, we used amine-coupling to develop a novel recombinant N1N2 (rN1N2)-functionalized SPR biosensor by immobilizing rN1N2 proteins on gold substrates and using SPR to monitor the binding kinetics of the proteins with target bacteria. We observed rapid detection of V. cholerae in the range of approximately 10³ to 10⁹ CFU/ml but not of E. coli at any tested concentration, thereby confirming that the biosensor exhibited differential recognition and binding. The results indicate that the novel biosensor can rapidly monitor a target pathogenic microorganism in the environment and is very useful for monitoring food safety and facilitating early disease prevention.

• Journal of Bio-Environment Control
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• v.16 no.2
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• pp.108-114
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• 2007

This study was conducted to clarify the effects of the different mixing ratios of substrate mixtures based on peat moss and the concentration of nutrient solution on the growth of tomato (Lycopersicon esculentum Mill.) seedlings. Substrates such as peat moss, rice hull, carbonized rice hull, decomposed sawdust, perlite and granular rock wool were mixed and used. The concentration of nutrient solution were adjusted to EC $0.5{\sim}1.5mS/cm$. The volumetric moisture contents became higher as peat moss mixed were much more. Total porosities in all substrate mixtures were over 80%, and pH in substrate mixtures became lower as the volume of peat moss mixed higher. Mixing ratios of substrates suitable for the production of tomato seedlings with the higher quality were peat moss:rice hull:carbonized rice hull:decomposed sawdust:perlite=25:10:25:20:20(v/v). The plant growth was not significant among the different substrate mixtures. However, plant growth such as plant height, leaf area, and total dry weight became significantly increased as EC increasing.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1256-1266
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• 2004

2-Bromooctanoic acid (2-BrOA) is known to block the formation of polyhydroxyalkanoic acid (PHA) in Pseudomonasfluorescens BM07 without any influence on the cell growth when grown on fructose, but it inhibits the cell growth when grown on octanoate (OA) (Lee et al., Appl. Environ. Microbiol. 67: 4963- 4974, 2001). We investigated the role of 2-BrOA in the PHA synthesis of the bacterium grown with mixtures of fructose and fatty acids. OA, 11­phenoxyundecanoic acid (1 1-POU), and 5-phenylvaleric acid (5-PV) were selected as model substrates. When supplemented with 50 mM fructose, all these carboxylic acids suppressed the formation of PHA from fructose, however, the ~-oxidation coenzyme A monomers derived from the carboxylic acids were efficiently polymerized, but the conversion yield [(mol of carboxylate substrate converted into PHA)/(mol of carboxylate substrate in the feed)] was low (e.g., maximally $\~53\%$ for 5 mM 11-POU). Addition of 2-BrOA (up to 5 mM) to the mixed carbon sources raised the conversion yield sensitively and effectively only at low levels of the acid substrates (e.g., 2 mM 1 1-POU or 5 mM OA): For instance, $100\%$ of 2 mM ll-POU were converted into PHA in the presence of 5 mM 2-BrOA, whereas only $\~10\%$ of the 1 1-POU were converted in the absence of 2-BrOA. However, at highly saturated suppressing levels (e.g., 5 mM ll-POU), 2-BrOA inhibitor showed no significant additional effect on the conversion ($60- 70\%$ conversion irrespective of 2-BrOA level). The existence of competitive and compensative relationship between 2­BrOA and all the carboxylic acid substrates used may indicate 'Present address: Section on Brain Physiology and Metabolism, Bldg. 10, Rm. 6N202, National Institute on Agmg, National Institute of Health, Bethesda, MD 20892, U.S.A. that all the acid substrate-derived inhibiting species bind to the same site as the 2-BrOA inhibiting species does. We, therefore, suggest that 2-BrOA can be used for efficiently increasing the yield of conversion of expensive substituted fatty acids into PHA and then substituted 3-hydroxyacids by hydrolyzing it.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.40-46
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• 2007

This study was conducted to clarify the effects of the different substrates in terms of perlite (100%), peat moss (100%), granular rock wool (100%) and mixing perlite (50%) with peat moss (50%) on the growth responses and mineral contents of hydroponically grown Plantago asiatic in aggregate culture. Overall early plant growth such as plant height, stem diameter, number of leaves, root length, fresh and dry weight of shoot and root were increased in the order of that miked perlite and peat moss (50%:50%, v/v)>peat moss (100%)>granular rock wool (100%)>perlite (100%). Ca and Mg contents in plants became highest in the plants grown in the peat moss, however, Mg and Na in the granular rock wool. $P_2O_5$ content in plants were most increased in proportion to the plant growth increment in the peat moss (100%) and the mixing substrates of perlite and peat moss (50:50, v/v).

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.8-16
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• 2002

This study was performed to produce the high reactive lignin zero substrates from autohydrolyzed wood resources. In chemical compositions of used raw-materials, there were significant differences between two species, Japanese larch (Larix leptolepis) and oak (Quercus mongolica) woods. Japanese larch contained 25 to 3.5 times higher amounts of extractives than oak wood, which is mainly derived from high content of arabinogalactan in Japanese larch wood. Oak wood has 5% lower lignin content and 3% higher holocellulose and pentosans than larch wood. Concerned to changes in wood components during autohydrolysis pretreatment at 22 kg/cm² steaming pressure for 5~60 min, glucose content was constant during pretreatment, while hemicellulose and lignin were abruptly changed. Hemicellulose fraction was decreased significantly and lignin contents increased because of its condensation reaction with hemicellulose degradation products. The pH of hydrolyzates during pretreatment was decreased, reached upto pH 3 and since then leveled off. In the case of oak wood, same tendency was observed as in Japanese larch. Autohydrolysis followed by sodium chlorite and sulfite or bisulfite pretreatment was very effective in delignification of the substrates. In particular, two-stage delignification of autohydrolyzed woods with alkali and O₂-alkali resulted in very low lignin content substrates, such as 0~0.2% lignin substrate.

• Journal of Animal Science and Technology
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• v.50 no.5
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• pp.713-720
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• 2008

This study was conducted to isolate and identify xylanase- and cellulase-producing thermophilic bacteria from stacked spent mushroom substrates and to determine the optimal medium conditions for their growth. Bacteria with the highest xylanase and CMCase activities were strain 3 and 201-7. Both of them were identified as Bacillus spp. and named Bacillus subtilis KU3 and Bacillus subtilis KU201-7. The optimal medium condition of Bacillus subtilis KU3 was obtained when 3%(w/v) of yeast extract and 1%(w/v) of maltose were used as nitrogen and carbon sources, respectively. That of Bacillus subtilis KU201-7 was obtained when 0.5%(w/v) of yeast extract and 0.5%(w/v) of CMC were used as nitrogen and carbon sources, respectively.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.255-260
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• 2007

This study was conducted to isolate and identify bacteria producing xylanase and cellulase from spent mushroom substrates and to determine the optimal medium conditions for their growth. Bacteria showing high xylanase and carboxymethyl cellulase activities and low protease and amylase activities were strain 201-3 and strain 206-3. Strain 201-3 was identified as Enterobacter ludwigii and named Ent. ludwigii KU201-3. 206-3 was identified as Bacillus cereus and named B. cereus KU206-3. The optimal medium condition of Ent. ludwigii KU201-3 was obtained when 1%(w/v) of soybean meal and 3%(w/v) of sucrose were used as nitrogen and carbon source, respectively. That of B. cereus KU206-3 was obtained when 3%(w/v) of soybean meal and 1%(w/v) of molasses were used as nitrogen and carbon sources, respectively.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1080-1086
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• 2005

Membranes prepared from Vibrio natriegens oxidized both NADH and deamino-NADH as substrates. The maximum activity of the membrane-bound NADH oxidase was obtained at about pH 8.5 in the presence of 0.2 M NaCl, whereas that of the NADH:ubiquinone oxidoreductase was obtained at about pH 7.5 in the presence of 0.2 M NaCl. Electron transfer from NADH or deamino-NADH to ubiquinone-l or oxygen generated a considerable membrane potential (${\Delta}{\psi}$), which occurred even in the presence of $20{\mu}M$ carbonylcyanide m-chlorophenylhydrazone (CCCP). However, the ${\Delta}{\psi}$ was completely collapsed by the combined addition of $10{\mu}M$ CCCP and $20{\mu}M$ monensin. On the other hand, the activity of the NADH oxidase and the ${\Delta}{\psi}$ generated by the NADH oxidase system were inhibited by about $90\%$ with $10{\mu}M$ HQNO, whereas the activity of the NADH:ubiquinone oxidoreductase and the ${\Delta}{\psi}$ generated at the NADH:ubiquinone oxidoreductase segment were inhibited by about $60\%$. Interestingly, the activity of the NADH:ubiquinone oxidoreductase and the ${\Delta}{\psi}$ generated at the NADH:ubiquinone oxidoreductase segment were resistant to the respiratory chain inhibitors such as rotenone, capsaicin, and $AgNO_3$, and the activity of the NADH oxidase and the ${\Delta}{\psi}$ generated by the NADH oxidase system were very sensitive only to $AgNO_3$. It was concluded, therefore, that V. natriegens cells possess a $AgNO_3$-resistant respiratory $Na^+$ pump that is different from the $AgNO_3$-sensitive respiratory $Na^+$ pump of a marine bacterium, Vibrio alginolyticus.

• Journal of Microbiology and Biotechnology
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• v.18 no.8
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• pp.1408-1415
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• 2008

To produce polyhydroxyalkanoate (PHA) from inexpensive substrates by bacteria, vegetable-oil-degrading bacteria were isolated from a rice field using enrichment cultivation. The isolated Pseudomonas sp. strain DR2 showed clear orange or red spots of accumulated PHA granules when grown on phosphate and nitrogen limited medium containing vegetable oil as the sole carbon source and stained with Nile blue A. Up to 37.34% (w/w) of intracellular PHA was produced from corn oil, which consisted of three major 3-hydroxyalkanoates; octanoic (C8:0, 37.75% of the total 3-hydroxyalkanoate content of PHA), decanoic (C10:0, 36.74%), and dodecanoic (C12:0, 11.36%). Pseudomonas sp. strain DR2 accumulated up to 23.52% (w/w) of $PHA_{MCL}$ from waste vegetable oil. The proportion of 3-hydroxyalkanoate of the waste vegetable-oil-derived PHA [hexanoic (5.86%), octanoic (45.67%), decanoic (34.88%), tetradecanoic (8.35%), and hexadecanoic (5.24%)] showed a composition ratio different from that of the corn-oil-derived PHA. Strain DR2 used three major fatty acids in the same ratio, and linoleic acid was the major source of PHA production. Interestingly, the production of PHA in Pseudomonas sp. strain DR2 could not occur in either acetate- or butyrate-amended media. Pseudomonas sp. strain DR2 accumulated a greater amount of PHA than other well-studied strains (Chromobacterium violaceum and Ralstonia eutropha H16) when grown on vegetable oil. The data showed that Pseudomonas sp. strain DR2 was capable of producing PHA from waste vegetable oil.

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.350-354
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• 2010

In natural world various inorganic crystals are grown with controlled shape and size in hybrid forms with organics. Such natural processes have been attempted much to mimick artificially. One of the example is calcium carbonate which has been examined a lot in the field of biomineralization. In this study, we utilize well-organized surface of polydiacetylene(PDA) films as the crystal-growing template. We devised a novel mini-arrayer device that transfers PDA films at air/water interfaces of each array well and deposit them to hydrophobized glass substrates. This technical improvement will contribute to facilitate better understandings of biomineralization mechanism.