• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.482-486
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• 1996

Batch fermentations of lactic acid were performed with Lactobacillus casei to investigate the effect of pH on cell growth and production of lactic acid and by-products. Maximum productivity of lactic acid increased with increasing pH from 5.0 to 6.5, and the extent of D-lactate production was different at each pH. Acetate and D-lactate concentrations increased even after the complete consumption of glucose in the medium. While a pH range of 6.0-6.5 was optimal for cell growth and lactic acid production, superior results were achieved at pH 6.0 when both maximum lactic acid productivity and minimum by-product formation were considered.

• Journal of Korean society of Dental Hygiene
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• v.8 no.3
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• pp.139-148
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• 2008

A fluorine solution was used to measure the growth of S.mutans and the pH changes were also measured in order to find an effective and preventative dentistry lab within a limited time for the dental hygiene department curriculum and the following results were obtained. 1. In the growth comparison of S.mutans, the culture medium of the experiment group with fluorine weighed 0.3g and the culture medium with no fluorine weighed 0.5g, which shows that the growth rate of S.mutans is significantly decreased in the culture medium with the fluorine. 2. The pH7.8 of the culture medium was not nearly changed; it became 7.0 after culturing with fluoride, however the pH was significantly decreased to 3 in the culture medium that had no fluorine. 3. Since it has been proven that the fluorine can control the growth of germs, it is believed that the effect of fluorine as a cavity preventative should be emphasized to students and in addition, it will help students transmit the effect of fluoride to their patients since this knowledge has been acquired through practice. 4. It is considered that this is a simple test protocol providing effective results in the microorganism and preventive dentistry lab within a limited time and furthermore, it will furnish the students of dental hygiene with comprehensive accessibility to dental hygiene curriculum.

• Journal of Life Science
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• v.13 no.4
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• pp.498-504
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• 2003

This Study was carried out to investigate the optimal mycelial growth of Pholiota nameko. The optimal medium for the mycelial growth was ME medium. The optimal temperature and pH were $25^{\circ}C$$\pm$1 and 5.5, respectively. The modified optimal medium compositions were glucose 3% (w/v), malt extract 0.25% (w/v), yeast extract 0.25% (w/v), $KH_2PO_4$ 0.046% (w/v), $K_2HPO_4$ 0.1% (w/v), $MgSO_4$ㆍ$7H_2O$ 0.05% (w/v). From the result of experiments on the optimal temperature, pH and nutritional requirements, the mycelial growth of modified optimal medium was higher than that of ME medium.

• Journal of Biosystems Engineering
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• v.17 no.4
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• pp.344-353
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• 1992

This study was carried out to develop a fully-controlled plant growth system for studying the effects of environmental factors on plant growth. The plant growth system consists of the growth chamber, the measurement system for sensing and signal conditioning the environmental factors and the control system which includes control algorithm required for optimum operation and on-line monitoring. The results of the study on the performance of the controlled plant growth system are summarized as follows : 1. Under the light intensity of 18,000~20,000 lux, the temperature was controlled in the range of $22{\pm}0.4^{\circ}C$, the relative humidity of $70{\pm}5%$ respectively. 2. The $CO_2$ concentration was controlled in the range of $1,000{\pm}40ppm$(from 1st to 4th day) and $1,500{\pm}40ppm$(from 4th to 9th day). 3. The electric conductivity(EC) and pH of the nutrient solution were controlled in the range of $1.9{\pm}0.2mS/cm$ and $6.8{\pm}0.5pH$ respectively. 4. Under the above environmental conditions, the average fresh weight of leaf lettuce increased from 10g to 74g in 9 days with 24 hour lighting.

• Korean Journal of Environmental Biology
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• v.18 no.3
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• pp.315-322
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• 2000

Effects of the simulated acid rain on the growth response and the structural features were studied with the 3 month old seedlings of G. biloba and P. thunbergii treated with acid rain of pH 5.6, 4.0, 3.2, and 2.4. The diameter and area of tracheid cells in the transectioned stem of G. biloba decreased with acidity of simulated acid rain. The wall thickness of tracheid cells was the thinest at pH 2.4, but there was no different at other levels of pH. Increasing of the acidity, the height of tracheid cells were reduced steadily. The diameter and area of tracheid cells of the transectioned root reduced with decreasing pH of acid rain, but those at pH 3.2 were larger than those at control. The wall thickness and height of tracheid cells of root were gradually decreased with acidity of acid rain. The size variation of the fusiform cambial initials in the stem of G. biloba sections tangentially showed a shortening tendency with treatment of acid rain. The length of ray initials was the shortest at pH 2.4 and reduced with decreasing pH of acid rain. The diameter, area, wall thickness, and height of the tracheid cells in P. thunbergii stem and root decreased with decreasing pH of acid rain. The areas of the pith, cortex, and xylem in P. thunbergii treated with acid rain decreased, but the cortex and pith areas increased significantly after exposure to acid rain of pH 3.2 compared with control.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.421-428
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• 1989

A soil bacterium synthesizing an extremely viscous biopolymer was isolated and identified as Pseudomonas delafieldii. The optimal pH and temperature for the growth were 6.5 and 3$0^{\circ}C$, respectively. Maximum specific growth rate was 0.24 h$^{-1}$. The specific polysaccharide productivity, growth yield and product yield were 6.25 mg/g-cell/h, 54.5% and 38.39%, respectively. The polysaccharide was presumed to be $\beta$-glucan containing glucose and gluconolactone (1.9：1.0 in molar ratio) and 1.35 % acetyl group, Element analysis showed that it contained carbon (31.85%) and hydrogen (5.15%). The weight average molecular weight by GPC was 5.64$\times$10$^7$. The intrinsic viscosity was 42.84 dl/g.

• The Korean Journal of Mycology
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• v.49 no.1
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• pp.45-55
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• 2021

Artomyces microspora is a genus of coral fungi from the family Auriscalpiaceae that have sporophores which are clavarioid, profusely and pyxidately branched, and devoid of a conspicuous stipe. These fungi can be found in summer and fall. This study aimed to decipher fundamental information regarding optimal growth conditions of Artomyces microsporus mycelia, including pH, temperature, carbon sources, and nitrogen sources. Based on the assessment of colony diameter and mycelial density, the optimal culture medium, temperature, and pH for mycelial growth were found to be PDA, 25 ℃, and pH 5.0, respectively. Furthermore, the study revealed that the optimal carbon and nitrogen sources for mycelial growth were 1% soluble starch and 2% malt extract, respectively. The other suitable inorganic nitrogen sources were deemed to be 0.1% NH₄H₄PO₄ and 0.1% aspartic acid.

• Journal of Korean Society of Forest Science
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• v.46 no.1
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• pp.10-20
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• 1980

This experiment was carried out to investigate the effects of physico-chemical properties of soil on the growth of Chamaecyparis obtusa and to apply the results to such rational forest management as yield forecast and selection of suitable species for a given forest stand. The soil properties observed in this experiment were soil pH, exchangeable pH organic matter, total nitrogen, available $P_2O_5$, cation exchange capacity, exchangeable $H^+$, total base and base saturation. Diameter at breast height (DBH), height and volume growth of C. obtusa were observed at 78 sampling sites. Data were processed into the following series for the analysis of multivariates : inner correlation matrix, multiple correlation coefficients, regression coefficients and partial correlation coefficients. The results are summerized as follows : 1. Multiple correlation coefficients between soil properties and DBH of C. obtusa were .364 for 20-year trees, resulting less efficient for estimating the growth of C. obtusa. However, total base, soil pH and base saturation were considerable characters for better estimation. 2. More efficient multiple correlation coefficients were observed between soil properties and height growth than those between soil properties and DBH, showing .443 for 20-year trees and factors affecting the height growth were similar to those of DBH. 3. Extremely low values of multiple correlation coefficients were estimated between physico-chemical properties of soil and volume growth of C. obtusa resulting low efficient estimation. However, total base contributed highly to volume growth of C. obtusa. Accordingly the most contributable factor for estimating the growth of C. obtusa were total base, soil pH and base saturation. Consequently, these results can be effective for selecting of the reforesting site, and less effective for estimating the growth of C. obtusa.

• Journal of Plant Biology
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• v.20 no.2
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• pp.63-69
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• 1977

Experiments were conducted to investigate the effects of several hormones on the growth of suspension culture of carrot (Daucus carota L.) cells, where changes in pH and the amount of $NH_4-Nin$ the medium were observed with regard to growth. A treatment with 2,4-D at $10^{-5}M$ resulted in a highest rate of growth; the hormone at this concentration caused an increase in dry weight by about 40 to 50% over the control, measured at a stationary phase. It was thus indicated that 2,4-D at $10^{-5}M$ provided the optimal condition for the suspension culture. Changes in pH of the medium were found to be affected by hormonal treatments during the first 2-3 days following the inoculation, after which the pattern of pH changes in hormone enriched media paralleled that of the control. Subsequent changes of $NH_4-N and NO_3-N$ from the medium by the cells, and also by growth of the cells. The uptake of $NH_4-N$ by the cells did not appear to be influenced by hormonal treatments. At a stationary phase, a considerable amout of $NO_3-N$ played a more important role than $NH_4-N$ in the growth of the carrot cell suspension culture.

• Journal of Korean Society of Forest Science
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• v.77 no.4
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• pp.453-459
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• 1988

The purposes of this study were to evaluate the effects of acid rain on tree growth and on the mycorrhizal formation and the effects of mycorrhizae on the host tolerance to acid rain. Simulated acid rain was applied for five months to Pinus $rigida{\times}taeda$ seedlings in pots inoculated with Pisolithus tinctorius (Pt) and Suillus luteus (Sl). Mycelial inocula of Pt and Sl were either mixed with entire pot soil (Mix) or casted as a band (Band) after soil sterilization. Three pH levels of acid rain (pH 3.0, 4.5 and 6.4 adjusted by 3 : 1 mixture of sulfuric and nitric acids) were tested. Pt-Mix was most effective in growth stimulation and resulted in 45-90% increase in tree height in sandy loam. Pt-Band was less effective than Pt-Mix in growth stimulation and mycorrhizal formation. Simulated acid rain at pH 4.5 stimulated height growth by 10-55%, while acid rain at pH 3.0 did not significantly affect the height growth. The top/root ratio was increased by pH 4.5 treatment, while pH 3.0 treatment reduced it. Mycorrhizal infection rate was not affected by acid rain. Pt inoculation reduced acid-induced leaf injury by 28-58% in both pH 3.0 and 4.5 compared with un-inoculated plants. Sl was also effective in growth enhancement, but was less effective than Pt in both mycorrhizal infection and reducing leaf injury.