• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.431-437
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• 2005

In this study, the profiles of the bacterial regrowth of indigenous bacteria in tap water and Pseudomonas fluorescence P17 were investigated for cases when carbon (glucose), and/or nitrogen ($NO_3^-$-N), and/or phosphorus ($PO_4^{3-}$-P) were added below sufficient nutrient concentration (SNC) and when carbon sources (glucose and acetate) and nitrogen sources ($NH_4^+$-N and $NO_3^-$-N) were added together. The bacterial regrowth was decreased with limitation of nutrients, and were lowered relatively in the sample, which plural nutrients were limited. In addition, phosphate might be the effective nutrient to control the bacterial regrowth in drinking water because the bacterial regrowth was significantly decreased by the limitation of phosphate. In contrast, the bacterial regrowth was retarded with increasing the concentration of $NO_3^-$-N. For simultaneously adding carbon(glucose or acetate) and nitrogen sources ($NH_4^+$-N and $NO_3^-$-N), the regrowth counts appeared highly in the condition, for both glucose and acetate. And, the regrowth was increased with increasing $NH_4^+$-N concentration as a nitrogen source.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.309-315
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• 2005

In this study, the bacterial regrowth characteristics in drinking water were investigated for various nutrient concentrations and forms using improved BRP method as a traditional approach and specific regrowth rate as a new index. The results of bacterial regrowth potential for glucose and $NH_4^+-N$, which was evaluated by BRP method as a traditional index, appeared to be higher relative to that of acetate or humic acids as carbon source and $NO_2^--N\;or\;NO_3^--N$ as nitrogen sources, respectively. The results obtained by specific regrowth rate as a new index were similar to that of BRP method with respect to the nutrient conditions examined in this study; i.e., the specific regrowth rate for glucose(ranged from 0.005 to $0.082\;hr^{-1}$) was feater than that acetate and humic acids(ranged from 0.005 to $0.068\;hr^{-1}$ and from 0.005 to $0.008\;hr^{-1}$, respectively). And specific regrowth rate for $NH_4^+-N$ (ranged from 0.008 to $0.072\;hr^{-1}$) was feater than that $NO_2^--N\;and\;NO_3^--N$ (ranged from 0.008 to $0.055\;hr^{-1}$ and from 0.008 to $0.059\;hr^{-1}$, respectively). Therefore, specific regrowth rate can be applied in order to evaluate the bacterial regrowth potential in drinking water.

• Journal of Food Hygiene and Safety
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• v.16 no.2
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• pp.89-95
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• 2001

This study was conducted to find material having antibacterial activity. The effects of preservatives, antibiotics and oriental medicines on growth of teated microorganisms were investigated. The growth of all tested bacteria was inhibited by water extract of Schizandra chinensis. Antibacterial activity on the concentration of Schizandra chinensis extract was tested. The growth of Escherichia coli W3110, Enterobacter colacae MG82 and Salmonella typhimurium was extraordinarily inhibited by more than 0.2% concentration of Schizandra chinensis extract. The specific growth rate of Escherichia coli W3110, Enterobacter cloacae ME82 and Salmonella typhimurium under control conditin had mean values of 0.514(hr￣), 0.381(hr￣) and 0.489(hr￣), respectively. When 0.2% of Schizandra chinensis extract was added, specific growth rates of Escherichia coli W3110, Enterobacter colacae MG82 and Salmonella typhimurium wre decreased, compared to contorl, in 1.26, 2.23 and 1.50 fold, respectivley. Minimal inhibiotory concentration of Schizandra chinensis extract was 0.25% on the tested microorganisms The growth of Enterobacter cloacae MG82 was more inhibited by Schizandra chinensis extract than other tested microorganisms.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.91-96
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• 1992

Twenty kinds of medicinal herbs were extracted by water and 95% ethanol and then antimicrobial activity of the extracts was investigated against various kinds of microorganisms. Water extracts of Gardeniae fructus (Gardenia jasminoides), Lycii fructus (Lycium chinense) and Schizandrae fructus (Schizandra chinensis) showed inhibitory effects on the growth of most of the bacteria. In the case of ethanol extracts, the 3 kinds of the samples such as Gardeniae fructus, Schizandrae fructus and Lithospermi radix (Lithospermum erythrorhizon) showed inhibitory effects on the growth of almost all bacteria. In particular, ethanol extract from Phellodendri cortex (Phellodendron amurense) showed the best inhibitory effect on the growth of S. aureus in the concentration of 0.01%. By the way, inhibitory effects of water extracts from these medicinal herbs were not so good on the growth of fungi but those of ethanol extracts were better and ethanol extracts of Phellodendri cortex showed best. Antimicrobial activity was variable according to the used extracting solvent. For example, inhibitory effets of ethanol ext-racts were $2{\sim}100$ times better than those of water extracts. Ethanol extract of Lithospermi radix was the most effective not only bactericidal effects but also sensory evaluation tests for tastes.

• The Korean Journal of Malacology
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• v.15 no.1
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• pp.49-55
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• 1999

Mass mortality of the horned turban shell, Batillus cornutus was investigated using histological and bacteriological methods. Some pathogenic bacteria were isolated from mortal or inactive individuals. The pathogenic agents causing mortality of the horned turban shells were as Vibrio alginolyticus and V. anguillarum. Laboratory experiment indicated that optimal growth temperature of two bacteria was 25 to 30$^{\circ}C$ and 3% of NaCl. Histological examination of the horned turban shells showed that gill necrosis is one of the major symptom of infected individuals. It was believed that sudden increase of those two bacterial agents due to environmental change cause mortality of horned turban shells.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.331-338
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• 2000

The algicidal effects of marine bacteria were investigated and a strain, which had the strongest algicidal activity against the harmful dinoflagellate, Cochiodinim polykrikoides was selected. The bacterium was isolated in seawater during the period of blooming of C. polykrikoides in Masan Bay. This algicidal bacterium was identified as Micrococcus sp. LG-5 by means of morphological and biochemical tests. The optimal culture conditions of Micrococcus sp, LG-5 were $25^{\circ}C,\;pH 7.0\;and\;3.0{\%}$ NaCl concentration. The algicidal activity of Micrococcus sp. LG-5 was significantly increased to maximum value in the late of logarithmic phase of cell cuture. In addition, the culture filtrate ($pore size,\;0.1{\mu}m$) of Microcoocus sp. LG-5 showed strong algicidal effects. The cell numbers of C. polykikoides were decreased from $1.2{\times}10^4 cells/ml\;to\;less\;than\;2{\times}10^3\;cells/ml$ within 3, 6, 30 hours at the concentrations of culture filtrate $10{\%},\;5{\%}\;and\;1{\%}$, respectively. These results indicated that the algicidal effect was mediated by certain substances released from Microooccus sp. LG-5.

• Journal of Environmental Health Sciences
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• v.28 no.5
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• pp.42-52
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• 2002

Two full-scale distribution systems, one treating water by ozonation and another treating water by nanofiltration in parallel with lime softening, were monitored for bacterial growth. Both systems kept disinfectant residuals surf as chlorine and chloramine in their respective distribution systems. Bacterial growth was assessed by heterotrophic plate counts (HPC) on R2A agar. In the distribution systems fed by ozonated water, HPCs were correlated ($R^2$= 0.97) using an exponential model with the assimilable organic carbon (AOC) at each sampling site. Also, it was observed that ozonation caused a significant increase in the AOC concentration of the distribution system (over 100％ increase) as well as a significant increase in the bacterial counts of the distribution system (average increase over 100％). The HPCs from the distribution systems fed by nanofiltration in parallel with lime-softening water also displayed an exponential correlation ($R^2$ = 0.75) with an exponential model based on AOC. No significant correlation was found between bacteria growth on R2A agar and BDOC concentrations. Therefore, in agreement with previous work, bacterial growth in the distribution systems was found to correlate with AOC concentrations.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.283-288
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• 1995

This study was carried out to investigate the toxic action of herbicide, paraquat(1,1'-dimethyl-4,4'-bipyridylium-dichloride), against microorganisms. The toxic effect of paraquat was observed mainly using Escherichia coli(KCTC 1039), as follows; Growth of aerobic microorganisms which comprise 4 strains of bacteria and 2 strains of yeast and 4 strains of mold was inhibited drastically in the presence of 1.0mM paraquat But the growth of anaerobic bacteria was not affected by the chemical. When actively growing cells of E. coli were exposed to the paraquat at the concentration higher than 1.0 mM, they rapidly lost their ability to form colony and clearly formed inhibitory zone by well test More than 50% of the cells were killed by 1.0 mM paraquat treatment, even at immediate addition of paraquat to the medium.

• Food Science and Preservation
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• v.11 no.2
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• pp.207-213
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• 2004

Methanol extracts were prepared from 32 medicinal herbs of the extracts were tested their microbial inhibition activities against food borne pathogens and/or food poisoning microorganisms, food-related bacteria and yeast. Methanol extracts of Cinnamomum cassia, Paeonia suffruticosa, Alnus japonica, Eugenio caryophyllata and Illicium verum exhibited antimicrobial activity for the microorganisms tested, except lactic acid bacteria and yeast. Minimum inhibitory concentrations(MIC) were about 5 mg/mL for Bacillus subtilis, Staphylococcus epidermidis and Pseudomonas aeruginosa. Cell growth of lactic acid bacteria was inhibitied, but greatly on Leuconostoc mesenteroides. The phenolic compound contents were 10.98 mg/g, 10.31 mg/g, 8.55 mg/g and 6.69 mg/g in Thea sinensis, Eugenia caryophyllata, Alnus japonica and Artenisia capillaris, respectively. Antimicrobial activity appeared to be related to phenol compound content in medicinal herbs. The methanol extracts of medicinal herbs could be suitable for the development of a food preservative.

• Microbiology and Biotechnology Letters
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• v.30 no.2
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• pp.177-183
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• 2002

The extracts from approximately 40 different Korean traditional medicines were prepared to investigate the antimicrobial activities against poultry disease-related bacteria. Among tested, the extracts of Schizandra chinensis (SC), Melia azedarach (MA), Caesalpinia sappan (CS) and Rhus javanica (RJ) exhibited significant antimicrobial activities against Salmonella gallinarum, whereas the extracts of Elsholtzia ciliata (EC), Myristica fragrans (MF), Alpinia katsumadai (AK), Poncirus trifoliata (PT), Prunella vulgaris (PV), CS and RJ exhibited antimicrobial activities against Staphylococcus aureus. Minimum inhibitory concentrations (MIC) of MA, CS and RJ extracts against S. gallinarum were 1.2 mg/ml, whereas MIC of RJ extract for S. aureus was 0.6 ㎎/ml, which was the lowest among tested. The antimicrobial activities of SC and RJ extracts against S. gallinarum were reduced, but those of AK and CS extracts against S. aureus were not affected by heating treatment. The antimicrobial activities of SC extract against S. gallinarum and those of EC, PT and RJ extracts against S. aureus were stable by acid treatment but unstable by alkaline treatment. those of CS extract was not effected by either acid or alkaline treatment. The growth of all bacteria was significantly inhibited within 24 hours by the addition of at least 100 ppm and 300 ppm of RJ and CS extracts, respectively, compared with the control group. In conclusion, these findings suggest that RJ and CS extracts may play important roles for antimicrobial activities against poultry disease-related bacteria.