• Journal of Microbiology and Biotechnology
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• v.21 no.5
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• pp.519-524
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• 2011

The correlation between alcoholic fermentation rate, measured as carbon dioxide ($CO_2$) evolution, and the rate of hydrogen sulfide ($H_2S$) formation during wine production was investigated. Both rates and the resulting concentration peaks in fermentor headspace $H_2S$ were directly impacted by yeast assimilable nitrogenous compounds in the grape juice. A series of model fermentations was conducted in temperature-controlled and stirred fermentors using a complex model juice with defined concentrations of ammonium ions and/or amino acids. The fermentation rate was measured indirectly by noting the weight loss of the fermentor; $H_2S$ was quantitatively trapped in realtime using a pre-calibrated $H_2S$ detection tube which was inserted into a fermentor gas relief port. Evolution rates for $CO_2$ and $H_2S$ as well as the relative ratios between them were calculated. These fermentations confirmed that total sulfide formation was strongly yeast strain-dependent, and high concentrations of yeast assimilable nitrogen did not necessarily protect against elevated $H_2S$ formation. High initial concentrations of ammonium ions via addition of diammonium phosphate (DAP) caused a higher evolution of $H_2S$ when compared with a non-supplemented but nondeficient juice. It was observed that the excess availability of a certain yeast assimilable amino acid, arginine, could result in a more sustained $CO_2$ production rate throughout the wine fermentation. The contribution of yeast assimilable amino acids from conventional commercial yeast foods to lowering of the $H_2S$ formation was marginal.

• Food Science of Animal Resources
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• v.22 no.2
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• pp.164-171
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• 2002

The purpose of this study was to evaluate inhibitory activity of a bacteriocin mixture from lactic acid bacteria(LAB) against foodborne pathogens. Each bacteriocin solutions were prepared by growing nine strains of bacteriocin producers in MRS broth for 18~24 h followed by centrifugation(8000$\times$g, 20 min, 4$^{\circ}C$). Bacteriocins were purified from ammonium sulfate precipitation and were resuspended in 50 mM phosphate buffer(pH 7.0). Nine bacteriocins were mixed together and then allowed to freeze at -2$0^{\circ}C$. The mixture of nine bacteriocins showed enhanced inhibitory activity compared to each of bacteriocins and inhibited the Gram negative pathogens including Escherichia coli 0157:H7, Klebsiella pneumoniae, Pseudomonas chlororaphis and Shigella sonnei. The mixture of bacteriocin solutions was significantly lower than controls when a freeze-dried bacteriocin mixture was added to frank sausage, Mozzarella cheese and pork loin. With addition of bacteriocin mixture, total mesophilic bacteria in pork loin were constant over storage period, whereas total mesophilic bacteria in Mozzarella cheese and frank sausang slightly increased. Total viable cells of control group increased during storage without bacteriocin treatment. Volatile base nitrogen content of pork loin during storage also increased significantly without bacteriocin treatment. The bacteriocin mixture was capable of inhibiting pathogenic and spoilage microorganisms and extending the shelf-life of cheese and meat products during storage.

• Journal of Plant Biology
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• v.35 no.1
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• pp.91-95
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• 1992

Changes of contents of reducing sugar and sucrose and activities of sucrose-phosphate synthase, sucrose synthease and invertase from the leaves of barley (Hordeum vulgare L. cv. Chalssal) seedlings grown at $4^{\circ}C$ were investigated, and the property of acid invertase were also examined. In the seedlings grown at $4^{\circ}C$ for 3 days, the contents of reducing sugar and sucrose were increased to 1.3 and 2.4 times, respectively. Activity of acid invertase was decreased markedly by cold treatment while the activities of sucrosephosphate synthase, sucrose synthase, and alkaline invertase were not changed. In acid phosphatase purified partially by ammonium sulfate fractionation and DEAE-Sephacel column chromatography, the $K_m$ value for sucrose was 9.5 mM and the optimum pH and temperature was 5.5 and $35^{\circ}C$ respectively. This enzyme was supposed to be ${\beta}-fructosidase$ by studies on the substrate specificity and the molecular weight was estimated to be 63 Kd by Sephadex G-200 gel chromatography.graphy.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.414-419
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• 1991

Polyphenol oxidase from Jerusalem artichoke(Helianthus tuberosus L.) tubers was partially purified by precipitation with ammonium sulfate, followed by gel filtration on Sephadex G-100. The enzyme showed maximal activity at pH 6.5 and $4^{\circ}C$. Kinetic studies indicated $K_{m}$ value of 3 mM for catechol and activation energy of 72.6 kcal/mole. As for substrate specificity of polyphenol oxidase the enzyme showed high affinity towards diphenol compounds, but not towards monophenols. The enzamatic browning was completely inhibited at 1 mM concentration of L-ascorbic acid, sodium hydrosulfite and L-cystein(HCl). The activity of polyphenol oxidase in 0.1 M potassium phosphate buffer(pH 6.5) was fairly stable for a week at $4^{\circ}C$, while it decreased remarkably at $25^{\circ}C$.

• Journal of the Korean Wood Science and Technology
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• v.41 no.6
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• pp.559-565
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• 2013

This study evaluated the ability of white and brown rot fungi to decompose fire retardant-treated wood by measuring mass loss. Anti efficacy of FRT against sapstain and mold fungi was evaluated. Wood was treated with liquid sodium silicate and boric acid, ammonium borate, di-ammonium phosphate. Retardant treated wood was then subjected to fungal decay resistance tests performed according to KS standard method using a brown-rot fungus, Fomitopsis palustris and white rot fungus Trametes versicolor. Aspergillus niger, Penicillium funiculosum, Rhizopus nigricans, Aureobasidium pullulans, Tricoderma virede fungi were used anti-sapstain and mold test. Boron and phosphorus chemicals used in this study increased the resistance of fire retardant treated wood against both fungal attack. Anti mold and sapstain efficacy of the fire retardant treated wood was excellent but there were difference depend on mold. After the liquid sodium silicate treatment, the second chemical treatment process could lead chemical fixation into wood, which effects decay resistance.

• Microbiology and Biotechnology Letters
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• v.43 no.4
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• pp.330-335
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• 2015

The optimum conditions for the production of xylanase from Bacillus agaradhaerens DK-2386 have been previously investigated. In this study xylanase was purified by ammonium sulfate precipitation and CM-sepharose ion exchange chromatography. The molecular mass of the xylanase as determined by SDS-PAGE was 23 kDa in a form of monomeric enzyme. The optimum pH and temperature for xylanase activity was 6.0 and $60^{\circ}C$, respectively. Xylanase activity was increased by the addition of EDTA and then stabilized at $40^{\circ}C$ for 24 h. The maximum xylanase activity was obtained when Birchwood xylan was used as a substrate and the $V_{max}$ and $K_m$ were $49,724{\mu}mol/min$ and 6.08 mg/ml, respectively.

• Journal of Life Science
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• v.14 no.4
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• pp.608-613
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• 2004

Pyrimidine nucleotide N-ribosidase (pyrimidine 5'-nucleotide phosphoribo (deoxyribo) hydrolase/pyrimidine 5'-nucleoude nucleosidase, EC 3.2.2.10) directly catalyzes pyrimidine 5'-nucleotide to pyrimidine base and ribose (deoxyribo) 5-phosphate. In order to clarify the best nutritional conditions for the growth and the pyrimidine nucleotide N-ribosidase production of Pseudomonas oleovorans ATCC 8062 the effects of various nutrients such as different carbon and nitrogen sources were studied. For the both the growth and the enzyme production, 2% fumarate, 1.5% peptone, 5% corn steep liquor (CSL) and 1% ammonium chloride were excellent carbon and nitrogen sources, respectively. Optimum pH, temperature, and cultivation time for the enzyme production were 7.0, $28^{\circ}C$, and 48 h, respectively. The pyrimidine nucleotide N-ribosidase of P. oleovorans ATCC 8062 was not induced by UMP and its derivatives, and was constitutive enzyme.

• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.63-67
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• 2002

Bifidobacterium strain was isolated from the feces of brast fed infants. The isolated strain was identified as Bifidobacterium longum by 16S rRNA sequence analysis and named as Bifidobacterium SH2. The MRS medium was modified to obtain high density cells of Bifidobacterium SH2. The optimal medium was determined to be 50 g/L lactose, 10 g/L beef extract, 10 g/L peptone, 5 g/L yeast extract, 7 g/L sodium acetate, 2 g/L ammonium citrate, 2 g/L disodium phosphate,1 g/L tween 80, 0.2 g/L MnSO$_4$ and 0.5 g/L L-cysteine. The pH and temperature were optimized as 5.0 and $37^{\circ}C$, respectively. Through out the optimization of medium composition and culture conditions, the dry cell weight and viable cell count were 2.5 times and 1.8 times higer than those in MRS medium, respectively.

• Journal of Life Science
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• v.22 no.5
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• pp.575-581
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• 2012

This study was conducted to develop an economical optimum medium composition for the mass production of $Lactobacillus$ $plantarum$ and $Lactobacillus$ $reuteri$, livestock probiotics. Medium ingredient factors were selected on the basis of MRS broth composition, and the 15 ingredient variables were as follows: sucrose, glucose, molasses, yeast extract, corn steep liquor, soy peptone, dipotassium phosphate, manganese chloride, magnesium chloride, tween 80, sodium chloride, sodium acetate, ammonium citrate, sodium sulphate, and ferrous sulphate. The Plackett Burman design, consisting of 20 runs, was employed for the analysis of ingredient effects on cell growth of $L.$ $plantarum$ and $L.$ $reuteri$. As a result, sucrose, glucose, molasses, yeast extract, corn steep liquor, soy peptone, sodium acetate, and ammonium citrate positively influenced the growth of $L.$ $plantarum$. Additionally, yeast extract, soy peptone, $K_2PHO_4$, and tween 80 positively influenced the growth of $L.$ $reuteri$. Positive effects were found from sucrose, yeast extract, and soy peptone in the integrated analysis of the effects of both $L.$ $plantarum$ and $L.$ $reuteri$. Finally, effective medium components for both strains were found as follows: sucrose (20.0 g/l), glucose (5.0 g/l), soy peptone (11.0 g/l), yeast extract (5.0 g/l), $K_2PHO_4$ (0.2 g/l), $CH_3COONa$ (2 g/l), and $MgCl_2$ (0.02 g/l).

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.152-164
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• 1982

1. In order to make the improvement of plywood quality, this study has been made. The pretreatments applied to the veneers are as follows. a) The soaking treatment of the veneer in 30 percent methanol solution for 24 hours was applied to remove some resinous materials which may cause many stain discolouring on the face of finished plywood. b) The preservative treatment of the veneer in 2 percent malenit solution for 2 to 3 minutes was adopted to make resistance against decay and insect damages. c) The fire retardant treatment of the veneer in 40 percent ammonium phosphate solution for 2 hours was applied to give retardation effect against fire burning. 2. The results summarized in this study are as follows. a) One percent resinous materials was extracted, after the soaking of the veneers in 30 percent diluted methanol. b) No marks of the dirty stains of resinous materials on the face of the treated plywood was shown, although many quite dirty stains on the face of untreated plywood have contrary seen. c) However, the strip shear test strength of the treated plywood was not decreased. It means that there is no difference in the strength between the treated plywood and the untreated plywood. The strength values were 25.08 kg/$cm^2$ and 24.98 kg/$cm^2$, respectively. d) The strip shear test strength of plywood made of the treated veneers in 2 percent malenit solution was not decreased. e) The slight decrease of the strip shear test strength of the treated plywood made of the treated veneer in 40 percent ammonuim phosphate solution was shown. However, the remarkable difference of the fire retardation activities between the treated specimens and the untreated specimens has seen as in Table 10, that is, the fire proofed specimens had taken about 28 seconds to start to burn, while the untreated specimens had taken 15 seconds to reach to burning. This means that the fire retardation effect of the fire proofed plywood was greater than that of the unproofed plywood.