• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.2
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• pp.110-114
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• 2002

The relationship between the orientation of molecules adsorbed on $_TiO2$ and their photoproducts was examined by employing HBPCA (4-hydroxy-biphenylcarboxylic acid) as a model organic pollutant. For this purpose, the Photoproducts after irradiation with UV radiation at various pH were compared by utilizing UV and Raman spectroscopies. It was found from these studies that pH affected the photoproducts probably due to the different orientations of the adsorbed molecules, and that the orientation of the adsorbed molecules and their photoproducts were closely correlated.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.1
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• pp.41-48
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• 2008

Fermentative $H_2$ production was studied using microbial consortia isolated from heat-treated ($90{\circ}C$, 20 min) sewage sludge. Important parameters investigated were carbon(C) and nitrogen(N)-sources, C/N ratio, phosphate concentration, pH and temperature during anaerobic cultivation in serum bottles. Starch, ribose, sucrose and glucose were good C-sources for the culture growth and $H_2$ production. Yeast extract was better N-source than $(NH_4)_2SO_4$ or peptone when individually added to the synthetic media, however the combination of above three N-sources exhibited the additional effect for cell growth and $H_2$ evolution. Addition of 100 mM phosphate as a buffering agent prevented the rapid pH drop during the cultivation. The optimum initial pH for the cell growth was at 7.0, whereas $H_2$ production was observed at pH 5.5. Optimum temperature for the cell growth and $H_2$ production was $37{\circ}C$. Initial C/N ratio of 1.22 in the media using glucose and yeast extract as the C- and N-sources, respectively, showed the $H_2$ yield 1.0 mol $H_2$/mol glucose.

• Journal of Life Science
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• v.17 no.12
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• pp.1695-1700
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• 2007

The aim of this study was to estimate the ingestion effect of fermented soybean paste on the growth inhibition of Helicobacter pylori. Anti-H. pylori effect of the aqueous extract of soybean paste and cell-free supernatant of the isolates from soybean paste were determined using agar diffusion method. Soybean paste and the isolates inhibited the growth of H. pylori. Effect of soybean paste ingestion was estimated using urea breath test against infected volunteers showing no symptom of gastric disease. When 10 g of soybean paste was ingested 3 times a day for 6 weeks, average value of $P={\Delta}^{13}C(T_1-T_0)$ decreased from P=58 to P=28. This result indicated that fermented soybean paste was effective to inhibit the growth of H. pylori in gastric tissue.

• Preventive Nutrition and Food Science
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• v.5 no.3
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• pp.131-135
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• 2000

The inhibitory effect of various organic acids on the growth and survival of Escherichia coli O157:H7 in tryptic soy broth with 0.6% yeast extract at 37$^{\circ}C$ or 4$^{\circ}C$ was determined. Minimal inhibitory pHs of acetic acid, citric acid, fumaric acid, hydrochloric acid and lactic acid were 5.0, 4.0, 4.5, 4.0 and 4.5, respectively. Acetic acid (0.012 m) showed the strongest antimicrobial activity, based on the pH values or equivalent molar concentrations, followed by lactic acid (0.0006 M), fumaric acid (0.004M) and citirc acid (0.004 M), respectively, E. coli O157:H7 with an initial inoculum of {TEX}$10^{7}${/TEX} CFU/ml and {TEX}$10^{5}{/TEX} CFU/ml in tryptic soy broth supplemented with 0.6% yeast extract, acidified to target pH with citric, fumaric and lactic acids at 37$^{\circ}C$, was completely inactivated after 7 d and 5 d incubation, respectively, except for the acetic acid (9 d). The bactericidal effect decreased at the same pH when the incubation temperature a was reduced from 37$^{\circ}C$ to 4$^{\circ}C$. The pH values of 0.2% acetic (pH 5.1), 0.6% citric (pH 4.2) and 0.4% lactic acid (pH 4.3) in TSBYE were almost correspondent to the minimal inhibitory pH values on E. coli O157:H7 of acetic (pH 4.0), citric (pH 4.0) and lactic acids (pH 4.5).

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.1
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• pp.128-133
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• 2013

The objective of the study was to determine the effect of Acacia karroo supplementation on growth, ultimate pH, colour and cooking losses of meat from indigenous Xhosa lop-eared goats. Eighteen castrated 4-month-old kids were used in the study until slaughter. The kids were subdivided in two treatment groups A. karroo supplemented (AK) and non-supplemented (NS). The supplemented goats were given 200 g per head per d of fresh A. karroo leaves. The kids were slaughtered on d 60 and sample cuttings for meat quality assessment were taken from the Longistimus dorsi muscle. The supplemented kids had higher (p<0.05) growth rates than the non-supplemented ones. The meat from the A. karroo supplemented goats had lower (p<0.05) ultimate pH and cooking loss than the meat from the non-supplemented goats. Acacia karroo supplemented goats produced higher (p<0.05) $b^*$ (yellowness) value, but supplementation had no significant effect on $L^*$ (lightness) and $a^*$ (redness) of the meat. Therefore, A. karroo supplementation improved growth performance and the quality of meat from goats.

• Journal of Environmental Science International
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• v.23 no.6
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• pp.1003-1012
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• 2014

We examined the combined impacts of future increases of $CO_2$ and temperature on the growth of four marine diatoms (Skeletonema costatum, Chaetoceros debilis, Chaetoceros didymus, Thalassiosira nordenskioeldii). The four strains were incubated under four different conditions: present ($pCO_2$: 400ppm, temperature: $20^{\circ}C$), acidification ($pCO_2$: 1000ppm, temperature: $20^{\circ}C$), global warming ($pCO_2$: 400ppm, temperature: $25^{\circ}C$), and greenhouse ($pCO_2$: 1000ppm, temperature: $25^{\circ}C$) conditions. Under the condition of higher temperatures, growth of S. costatum was suppressed, while C. debilis showed enhanced growth. Both C. didymus and T. nodenskioldii showed similar growth rates under current and elevated temperature. None of the four species appeared affected in their cell growth by elevated $CO_2$ concentrations. Chetoceros spp. showed increase of pH per unit fluorescence under elevated $CO_2$ concentrations, but no difference in pH from that under current conditions was observed for either S. costatum or T. nodenskioeldii, implying that Chetoceros spp. can take up more $CO_2$ per cell than the other two diatoms. Our results of cell growth and pH change per unit fluorescence suggest that both C. debilis and C. didymus are better adapted to future oceanic conditions of rising water temperature and $CO_2$ than are S. costatum and T. nodenskioeldii.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1811-1814
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• 2009

The effect of fermentation with mixed cultures of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus on the microbiological characteristics of oat extract was investigated. Changes in pH, titratable acidity and viable cell populations indicated that growth was better in mixed cultures of L. delbrueckii subsp. bulgaricus and S. salivarius subsp. thermophilus. Growth of S. salivarius subsp. thermophilus in oat extract was more rapid than growth of L. delbrueckii subsp. bulgaricus. Cooperative interaction between two cultures during fermentation of oat extract as in yogurt from cow's milk was observed, but the intensity was relatively weak.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.4
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• pp.483-492
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• 1986

To find out the responses of plant growth, nodulation, and yield of soybean and their varietal differences to different soil pH, 16 soybean cultivars were examined under three different levels of soil pH. In general, as the soil pH decreased, plant growth, nodulation, yield and yield component and protein con-tents of grains were decreased in most of cultivars studied. But there were significant varietal differences in the responses of the characters investigated to soil pH. Jangbaegkong was evaluated as the most tolerant cultivar to acid soil, and Ulsan, Bongeui, Hwanggeumkong, and LC7852 were also relatively torelant to acid soil. There were significant correlation between soil pH and grain yield in 7 cultivars among 16, but were not in other cultivars.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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• pp.304-310
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• 1995

A thermophilic bacterium producing the extracellular cellulase-free xylanase was isolated from soil and has been identified as Bacillus sp. The optimal growth temperature was 50$\circ$C and the optimal pH, 7.0. Under the optimal growth condition, maximal xylanase production was 2.2 units/ml in the flask culture. The enzyme production was induced by xylan and xylose, but was repressed by sucrose or trehalose. The partially purified xylanase was most active at 70$\circ$C. It was found that the enzyme was stable at 65$\circ$C for 10 hours with over 75% of the activity. The enzyme was most active at pH 7.0 and retained 90% of its maximum activity between pH 5.0 and pH 9.0 though Bacillus sp. was not grown on alkaline conditions (>pH 8.0). In addition, the activity of xylanase was over 60% at pH 10.0. At the ambient temperature, the enzyme was stable over a pH range of 5.0 to 9.0 for 10 h, indicating that the enzyme is thermostable and alkalotolerant. The activity of xylanase was completely inhibited by metal ions including Hg$^{2+}$ and Fe$^{2+}$, while EDTA, phenylmethylsulfonyl fluoride (PMSF), $\beta$-mercaptoethanol and SDS didn't affect its activity. The enzyme was also identified to exert no activity on carboxymethylcellulose, laminarin, galactomannan, and soluble starch.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.4
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• pp.297-301
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• 1990

The study was conducted to investigate the effects of diatomearth(pH 3 and CEC 20me/100g) on the adjustment of nursery soil pH and on the growth of rice seedling in the tray. The results are as follows ; 1. The soil pH and damping-off of rice seedling were decreased with increase in diatomearth application. 2. Ten to fifteen percent of diatomearth was required to adjuse the optimum soil pH range of 4.5-5.5. 3. Changes in nursery soil pH adjusted by diatomearth were less than those by sulfuric acid during the incubation period. 4. Diatomearth application increased dry weight and height of rice seedling.