• The Korean Journal of Mycology
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• v.32 no.2
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• pp.134-137
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• 2004

This study was carried out to determine the optimum culture conditions for Phellinus spp. known as white rot fungi showing anti-cancer activity. The optimum solid medium for mycelial growth at $25^{\circ}C$ was potato dextrose agar medium and optimum pH range was $6.0{\sim}8.0$, while all species showed reduced or no growth at pH 4.0. Most species showed good growth at $25{\sim}30^{\circ}C$. Out of 10 species of Phellinus examined, P. biscuspidatus was the best growing fungus in the range of pH $6.0{\sim}7.0$ based on mycelial density. Three species such as P. biscuspidatus, P. johnsonianus and P. lloydii could be grouped in mesophile fungi, showing $30{\sim}35^{\circ}C$ optimum temperature.

• Journal of Korean Society of Forest Science
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• v.80 no.2
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• pp.237-245
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• 1991

Artificial acid rain (pH 3.0, 4.0 and 5.0) was treated on thd seeds of 5 coniferous species to examine its effects on germination and seedling growth. Artificial acid rain was prepared by diluting sulfuric acid with ground water and ground water(pH 6.5) was used as control. Artificial acid rain was sprayed to seeded pots three times per week. About 5mm of artificial acid rain was treated each time from early April to early October, 1990. Germination, seedling establishment and seedling growth were measured and compared among the treatments. The results were summarized as follows ; 1. Germination, seedling establishment rate of Larix leptolepis and Picea koraiensis were highest on the pH 5.0 plot whereeas those of Abies holophylla and Cryptomeria japonica were highest on the control plot, and those of Abies koreana showed the highest value on the pH 3.0 plot. 2. The differences in seedling height growth of Larix leptolepis was signif- icant at 1% level among the treatment levels of acid rain, whereas those of other species were not significant, Height of Larix leptolepis, Abies koreana and Picea koraiensis were highest on the pH 4.0 plot, and that of Abies holuphylla and Cryptomeria japonica were highest on the pH 5.0 plot. 3. Seedling dry weight of Larix leptolepis and Abies holophylla differed significantly at 1% level among the treatments, but those of other species did not differ. Highest seedling dry weight of Larix leptolepis and Abies koreana were observed on the pH 4.0 plot, and that of Abies holophylla and Cryptomeria japonica did on the pH 3.0 plot, and that of Picea koraiensis did on the control plot. 4. With decrease of pH value of artificial acid rain, the number of injured needle and injured individual tended to be increased, obviously. 5. The differences of soil acidity were highly significant among the treatments for all species.

• The Korean Journal of Mycology
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• v.26 no.2 s.85
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• pp.265-274
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• 1998

This study was carried out to obtain the basic data for an artificial cultivation of Phellinus sp.. The optimum conditions for the mycelial growth on the different sawdusts (Quercus aliena, Morns alba and Alnus japonica) substrate of an isolated Phellinus sp. were optimized by response surface methodology. The ratio of rice bran addition to sawdust and the suitable moisture content for the mycelial growth in the all sawdust media were about 30% (w/w) and $65{\sim}70%$ (w/v), respectively. The initial pHs for the mycelial growth of Quercus aliena and Morns alba were in the range of $pH\;5{\sim}6$, whereas Alnus japonica was obtained at pH 6. The optimum temperature for the mycelial growth was about $25{\sim}30^{\circ}C$, depending on the different kinds of wood substrates. From the response surface analysis, the values of independent variables of Quercus aliena at stationary points were determined to be 31.01 % (w/w) of rice bran, pH of 5.31 and 69.03% (w/v) of moisture content, and the expected value of mycelial growth was about 8.32 cm. Both the ratio of rice bran addition to sawdust $(X_1)$ and moisture content $(X_3)$ were effective to the mycelial growth. In the case of Morns alba, the ratio of rice bran addition to sawdust, initial pH and moisture content at the stationary points were 28.77% (w/w), 5.28 and 69.8 (w/v),respectively, and the expected mycelial growth of 7.60 cm was obtained. Stationary points for the mycelial growth in the sawdust media of Alnus japonica were 28.74% (w/w) of rice bran, pH of 6. 04 and 66.96% (w/v) of moisture content, and the expected values of mycelial growth was about 5.38 cm. Based on the above results, there was correlations between the mycelial growth and independent variables, and the effect of rice bran $(X_1)$ and initial pH $(X_2)$ for the mycelial growth were higher than the moisture content $(X_3)$. The optimum species of sawdust media for the my celial growth of Phellinus sp. was in the order of Quercus aliena > Morns alba > Alnus japonica.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.349-354
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• 2004

Predictive growth model of Vibrio parahaemolyticus in modified surimi-based imitation crab broth was investigated. Growth curves of V. parahaemolyticus were obtained by measuring cell concentration in culture broth under different conditions ($Initial\;cell\;level,\;1{\times}10^{2},\;1{\times}10^{3},\;and\;1{\times}10^{4}\;colony\;forming\;unit\;(CFU)/mL$; temperature, 15, 25 37, and $40^{\circ}C$; pH 6, 7, and 8) and applying them to Gompertz model. Microbial growth indicators, maximum specific growth rate (k), lag time (LT), and generation time (GT), were calculated from Gompertz model. Maximum specific growth rate (k) of V. parahaemolyticus increased with increasing temperature, reaching maximum rate at $37^{\circ}C$. LT and GT were also the shortest at $37^{\circ}C$. pH and initial cell number did not influence k, LT, and GT values significantly (p>0.05). Polynomial model, $k=a{\cdot}\exp(-0.5{\cdot}((T-T_{max}/b)^{2}+((pH-pH_{max)/c^{2}))$, and square root model, ${\sqrt{k}\;0.06(T-9.55)[1-\exp(0.07(T-49.98))]$, were developed to express combination effects of temperature and pH under each initial cell number using Gauss-Newton Algorism of Sigma plot 7.0 (SPSS Inc.). Relative coefficients between experimental k and k Predicted by polynomial model were 0.966, 0.979, and 0.965, respectively, at initial cell numbers of $1{\times}10^{2},\;1{\times}10^{3},\;and\;1{\times}10^{4}CFU/mL$, while that between experimental k and k Predicted by square root model was 0.977. Results revealed growth of V. parahaemolyticus was mainly affected by temperature, and square root model showing effect of temperature was more credible than polynomial model for prediction of V. parahaemolyticus growth.

• KSBB Journal
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• v.18 no.6
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• pp.443-447
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• 2003

The microorganism was isolated from the night soil treatment plant for the removal of sulfur compounds. The growth conditions of the sulfur-oxidizing bacteria were investigated and the isolate characterized as Thiobacillus noveilus SRM. The optimal pH of Thiobacillus novellus SRM on cell growth was pH 7.0 and the optimal temperature was 30$^{\circ}C$ and the optimal air flow rate was 1 vvm, respectively. As a results of cell growth from the Monod plot, the specific growth rate was 0.032 hr$\^$-l/, $V_{max}$ was 1.43 hr$\^$-l/ and $K_{m}$ was 0.32, respectively. The thiosulfate oxidation by Thiobacillus novellus SRM was made of sulfate ion. The sulfate ion reduced pH and decreased cell growth.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.5
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• pp.856-862
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• 1994

In salt-preserved foods of every kinds, it was examined the growth condition of halophilic bacteria that induced a change of colour, taste, nutritive substance, a production condition of enzyme and a character of crude enzyme. Used bacteria is H. halobium a kind of extremely halophilic bacteria, and the required of optimum culture needed a quite long time of crude enzyme production is 168 hours. Optimum pH is about 7-7.5, so the traditional food of such neutrality pH as soybean paste and soy sauce particularly come into trouble because the growth can flourish in neutrality or alkaliescence, and the crude enzyme also appeared that best activation between pH 6 and pH 8. The optimum temperature is about 37$^{\circ}C$, the optimum temperature of enzyme is about 40 $^{\circ}C$ and the temperature stability is settled for 15 minutes and it is completely inactivated at 10 minutes. In the influence of each metal ion, Fe++ and Mn++ a stimulated the growth of H.halobium and the activation of enzyme, Cu++ and Zn++ were identified that made the growth and the activation of enzyme inhibit.

• Korean Journal Plant Pathology
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• v.13 no.4
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• pp.232-238
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• 1997

Culture conditions affecting mycelial growth and sporulation of P. theae, SP2, SP3 and P. longiseta which causing leaf blight on oriental persimmon leaf blight have been investigated. The optimum temperature for the mycelial growth and sporulation on potato dextrose agar was $25{\sim}30^{\circ}C$ in all the fungi, but was inhibited and finally arrested at 10 and $30^{\circ}C$. The optimum pH for mycelial growth and sporulation were ranged at pH 4.5~5.0 and 5.0~6.0 in all the fungi. Lenonian agar, potato sucrose agar and oatmeal medium were good culture media for the mycelial growth and sporulation of all the fungi. The effective sources of nitrogen and carbon for the mycelial growth were tryptone, glycine, starch, dextrose, galactose and lactose. Glutamic acid, peptone and tryptone were good nitrogen sources for sporulation of the fungi. Sucrose, starch and galactose were also good carbon sources for sporulation. Generally, vitamins had no effect on mycelial growth and sporulation. The pH of the potato dextrose broth inoculated with SP2, SP3 and P. theae and P. longiseta was changed from 7.0 to 4.5~4.7 and 5.0~5.4 after incubating for 10 days, respectively. But, the initial pH of the medium adjusted to 5.0 was lowered to 4.5~4.7 after incubating for 10 days.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.2
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• pp.138-145
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• 1989

Little information is available on the effects of low pH on nodulation and growth of subterranean clover cultivars. Plants of 11 cultivars were inoculated with an acid-tolerant strain of Rhizobium trifolii and grown for 28 days in continuously flowing nitrogen-free nutrient solutions maintained at six constant pH values from 4.0 to 6.5. At pH 4.0, 4 cultivars failed to nodulate and the remainder formed only a few nodules; nodulation was delayed by 2 to 3 days in this treatment. All cultivars nodulated at pH 4.5 but, with the exception of cv. Dwalganup, nodule numbers were significantly less than at $pH{\geq}5.0$. Only in cvv. Clare and Woogenellup were nodule numbers significantly greater at pH 6.5 than at 5.0. Whole plant dry matter yields were strongly depressed at pH 4.0(21 to 33% of maximum). At pH 4.5, relative yields of all cultivars except Dwalganup were significantly depressed without significant reductions in nodule dry weights, suggesting that nodule function was inhibited by acidity. These results are consistent with the view that nodulation and growth of plants dependent on symbiotic nitrogen fixation are much more sensitive to low pH per se than is host plant growth in the presence of adequate mineral nitrogen.

• Journal of Environmental Science International
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• v.6 no.2
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• pp.141-152
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• 1997

The pilot plant had been made so as to be an association system from the various items managed to have degrees of efficiency and It have been done to consider the experimental result with irradiance period and pH influence of all major things to treatment function of Waste Stabilization Pond. The results are as following. The attained results for continuous & cyclic irradiance 1. 24L.-reactor was prior to 12L.-12D.-reactor on oxygen generation & algal production ability. 2. 24L.-reactor was prior to 12L.-12D.-reactor on nutrients removal efficiency. 3. In 24L.-reactor it maintained 5mg/L∼6mg/L, DO concent enough to a fish's survival. The attained results for pH condition 1. Oxygen generation ^ algal production in pH 4-reactor were higher than those in pH 10-reactor. 2. The acidic condition at pH 4 and alkalic condition at pH 10 did not so much affect an algal growth and nutrients removal. The attained results for whole 1. In view of the results appeared as [(NH3-N)+(NO3-N)] removal efficiency, 89.1%∼93.9% and PO4-P removal efficiency, 34.3%∼83.7% & COD removal efficiency, 88.5%∼93.9%. It is possible to treat the wastewater with starch and pH which have been known as thedifficult problem. 2. At the point of non using methanol to nitrificate NO3-N, the nutrients removal method by using an algal growth is the most economical method in the whole nutrients removal methods. 3. The nutrients removal method by using an algal growth contributes to natural ecosystem. 4. The nutrients removal method by using an algal growth is excellant in the prevention against the eutrophication.

• The Plant Pathology Journal
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• v.21 no.2
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• pp.127-131
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• 2005

In this comparative study, the effects of temperature, pH, and bactericides on the growth of Erwinia pyrifoliae and Erwinia amylovora were investigated. The maximum temperature for the growth of both Erwinia species was estimated to be $36{\circ}C$. The maximum specific growth rates of E. pyrifoliae and E. amylovora were observed at $27{\circ}C$ and $28{\circ}C$, respectively, and no significant growth differences were shown at their optimum temperatures. However, at lower temperatures ranging from 12-$21{\circ}C$, E. pyrifoliae showed higher growth rates with doubling times shorter than those of E. amylovora. Distinct growth rates at these temperatures revealed that E. pyrifoliae is more cold-tolerant than E. amylovora. The optimum pH for the growth of both pathogens was 7.5 and growth was not seen at pH ${\le}$ 5.0 and ${\ge}$ 10.0. These results showed that the effect of pH on the growth of E. pyrifoliae and E. amylovora was similar. Minimum inhibitory concentrations (MICs) of copper sulfate, oxolinic acid, streptomycin, and tetracycline, which inhibited growth of E. pyrifoliae and E. amylovora, were determined. The strains of both pathogens were able to grow at 0.08-0.32 mM copper sulfate, but not at higher concentrations. However, none of the tested strains grew in the presence of oxolinic acid (0.001 mM), streptomycin (0.1 mM), and tetracycline (0.01 mM) concentrations. These results suggested that all strains of both Erwinia species were sensitive to tested bactericides and indicated no occurrence of resistant strains of E. pyrifoliae in Korea.