• Korean Journal of Microbiology
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• v.36 no.1
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• pp.74-78
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• 2000

Vibrio, Photobacterium, Alteromonas and Xenorhabdus species are capable of emitting light, called bioluminescence. They exist in marine, freshwater and terrestrial environments. Bacterial bioluminescent reaction is that reduced riboflavin phosphates and a long-chain aldehyde are oxidized in the presence of molecular oxygen and enzyme luciferase. This experiment aims to develop the proper culture media and to optimize the storage condition for the recovery of bioluminescent activity in Photobacterium phosphoreum. The Luria broth (LB) medium was modified for cultivation of Photobacterium phophoreum, called as modified LB(mLB) medium. The mLB medium is LB fortified with 3% glycerol and 1.5% NaCl. In mLB medium. bacterial growth and bioluminescent activity are 25% higher than those in a Nutrient broth medium. When the cell stocks were stored at $-20^{\circ}C$, $-70^{\circ}C$ and LN2 for 3 months, cell growth and bioluminescent activity of culture after stored at $-20^{\circ}C$ were better than those of other treatments. The highest bioluminescent activity obtained at the late exponential phase in all treatments. When the cell stock was freeze-dried with 5% adonitol as a cryoprotectant, the recovery of cell was better than those of control and freeze-dried cell stock without addition of cryoprotectant.

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.180-186
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• 1987

Cell suspensions of two isolates of Pseudomonas syringae. PS8401 from sweet persimon and PS8402 from tea plant, were active in ice nucleation at -2.5 and $-3.8^{\circ}C$, respectively. Ice nucleation at those temperature was, using micropipette method, detected in suspensions ($10^8$ olony forming unit/ml of distilled water) of cells that had been grown on nutrient agar supplemented with $2.5\%$ glycerol. Using the same method, on the other hand, the freezing temperature of distilled water only was approx. $-21.8^{\circ}C$, and those of various plant saps including corn were lower than $-11.6^{\circ}C$. Corn seedlings sprayed with cell suspensions $(10^8\;cfu/ml)$ of nutrient broth) of PS8401 began to be damaged at $-2^{\circ}C$ and were almost completely damaged at $-4^{\circ}C$, whereas seedlings sprayed with nutrient broth only were not injured until the temperature down to $-9^{\circ}C$. Amounts of frost damage measured 48 hr after application of PS8401 suspensions increased as applied bacterial cell densities were increased. Ice-nucleation activity of the cell suspensions in vitro increased with increasing the number of cells in suspension. The activity also affected by growth-medium composition or growth-temperature. Ice nucleation thus occured at -4.0, -4.4 and $-7.2^{\circ}C$ in suspensions $(10^2\;cfu/ml)$ of PS8401 that had been grown at$25\%$ nutrient agar with $2.5\%$ glycerol, nutrient agar with $2.5\%$ glucose and nutrient agar only, respectively, and occured at -4.0 and $-7.6^{\circ}C$ in suspensions $(10^2\;cfu/ml)$ of PS8401 hat had been grown on nutrient agar with $2.5\%$ glycerol at $15\~25^{\circ}C$ and $30^{\circ}C$, respectively.

• Food Science and Preservation
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• v.23 no.6
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• pp.759-764
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• 2016

This purpose of this study was to determine the best enrichment medium for rejuvenating and recovering Salmonella placed in cold temperature prior to the employment of the gold biosensor combined with a light microscopic imaging system. A mixture of nalidixic-resistant Salmonella Typhimurium and Enteritidis were inoculated onto chicken (1,000 CFU/chicken). After cold injury at $4^{\circ}C$ for 24 hr, Salmonella on chicken was enriched for 6 hr with six non-selective media including buffered peptone water broth, lactose broth, brain heart infusion broth (BHI), universal pre-enrichment broth, nutrient broth, and tryptic soy broth, and five selective media including brilliant green broth (BG), rappaport-vassiliadis R10 broth, selenite cystine broth, selenite broth, and tetrathionate brilliant green broth (TBG) for the comparison of Salmonella growth. Various concentrations of Salmonella (10, 50, 100, 500, and 1,000 CFU/chicken) were then enriched for 6 hr in both BHI and BG media to select the best media. BHI was selected as the most effective non-selective enrichment medium, while BG was selected as the most effective selective enrichment medium. Finally, BHI medium was selected as the most efficient enrichment medium for Salmonella growth injured from cold temperature during processing or storage.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.297-302
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• 1996

The effect of application rate of pig or chicken manure on the seasonal change of tomato(Minicarol) rhizosphere microflora was investigated by field experiment were surface soil(16cm) mixed with manures 1 weeks before transplanting. 1. Rhizobacteria population of control plot decreased 5 weeks after transplanting(WAT) than 1 WAT and 1.5~2 times higher colony counting was found in DNB(Diluted nutrient broth medium) than NB(Nutrient broth medium) at 15 WAT. 2. Rhizobacteria population at 1 WAT inereased in NB medium with the application rate of both manures but decreased in DNB with chicken manure. Colony counting in NB of 60 and 120 mg/ha treatment was 100 times higher than that of the control. However, rhizobacteria in DNB at 15 WAT(harvest stage) was much higher than that of NB. 3. Application rate did not affect fungi population 1 WAT in pig manure but decresed in chicken manure. At 15 WAT fungi population was 2 times higher than 1 WAT with chieken manure and highest in 30 mg/ha but with pig manure decreased with rate than the control. 4. Actinomycetes population at 1WAT was not different among pig manure rates and decreased with chicken manure than control. At 15 WAT population increased in all manure rates. especially in 10 mg/ha pig manure and 30 mg/ha chicken manure 4 times that 1 WAT.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.181-186
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• 2003

This study was performed to analyze quantitatively the number of living bacteria in forest soil samples collected from Mt. Keryong using improved direct viable count (DVC) and plate count (PC) methods. The number of living bacteria by DVC comprised 18～44% of the total direct count (TDC), whereas the number of living bacteria by PC was less than 1% of TDC. These results showed that viable but non-culturable (VBNC) bacteria existed in the soil with high percentages. Besides, DVC was proved to make it possible to make a quantitative detection of the VBNC bacteria. On the other hand, upon measuring the value from the conventional nutrient broth (NB) and $10^{-2}$ folded diluted nutrient broth (DNB), the values from the DNB showed 5 to 10 times higher than those from the conventional NB medium. These results indicate that oligotrophic bacterial groups, which could multiply in the low nutrient broth, abundantly exist in the soil ecosystem. It would also be possible to apply this kind of method to other substrate to make a quantitative detection of soil bacterial groups.

• Journal of Microbiology and Biotechnology
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• v.29 no.10
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• pp.1495-1505
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• 2019

The Burkholderia cepacia complex (BCC) is capable of remaining viable in low-nutrient environments and harsh conditions, posing a contamination risk in non-sterile pharmaceutical products as well as a challenge for detection. To develop optimal recovery methods to detect BCC, three oligotrophic media were evaluated and compared with nutrient media for the recovery of BCC from autoclaved distilled water or antiseptic solutions. Serial dilutions ($10^{-1}$ to $10^{-12}CFU/ml$) of 20 BCC strains were inoculated into autoclaved distilled water and stored at $6^{\circ}C$, $23^{\circ}C$ and $42^{\circ}C$ for 42 days. Six suspensions of Burkholderia cenocepacia were used to inoculate aqueous solutions containing $5{\mu}g/ml$ and $50{\mu}g/ml$ chlorhexidine gluconate (CHX) and $10{\mu}g/ml$ benzalkonium chloride (BZK), and stored at $23^{\circ}C$ for a further 199 days. Nutrient media such as Tryptic Soy Agar (TSA) or Tryptic Soy Broth (TSB), oligotrophic media (1/10 strength TSA or TSB, Reasoner's $2^{nd}$ Agar [R2A] or Reasoner's $2^{nd}$ Broth [R2AB], and 1/3 strength R2A or R2AB) were compared by inoculating these media with BCC from autoclaved distilled water and from antiseptic samples. The recovery of BCC in water or antiseptics was higher in culture broth than on solid media. Oligotrophic medium showed a higher recovery efficiency than TSA or TSB for the detection of 20 BCC samples. Results from multiple comparisons allowed us to directly identify significant differences between TSA or TSB and oligotrophic media. An oligotrophic medium pre-enrichment resuscitation step is offered for the United States Pharmacopeia (USP) proposed compendial test method for BCC detection.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.4
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• pp.558-565
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• 2012

The objective of this study was to develop a predictive growth model for Bacillus cereus in nutrient broth and validate the developed growth model in blanched vegetables. After inoculating B. cereus into nutrient broth, growth of B. cereus was investigated at 13, 17, 24, 30 and $35^{\circ}C$. Lag time (LT) decreased while specific growth rate (SGR) increased with an increase in storage temperature. Growth of B. cereus was not observed at temperatures lower than $12^{\circ}C$. Secondary growth models were developed to describe primary model parameters, including LT and SGR. Model performance was evaluated based on bias factor ($B_f$) and accuracy factor ($A_f$). In addition, we inoculated B. cereus into blanched vegetables stored at 13, 24, $35^{\circ}C$ and observed the growth kinetics of B. cereus in five different blanched vegetables. Growth of B. cereus was most delayed on Doraji at $13^{\circ}C$ and was not observed on Gosari at $13^{\circ}C$. Growth of B. cereus at $35^{\circ}C$ was significantly (p<0.05) slower on Gosari than on other blanched vegetables. The developed secondary LT model for broth in this study was suitable to predict growth of B. cereus on Doraji and Gosari, whereas the SGR model was only suitable for predicting the growth of B. cereus on mung bean sprout.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.142-146
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• 1996

옥수수 깜부기병균 Ustilago maydis 동포자를 풍건한 후 모래나 silica gel을 보존매체로 해서 4$^{\circ}C$나 그 이하 온도에서 24개월 두었을 때 동포자 생존율은 40~45%였다. 동포자는 28$^{\circ}C$ PDA상에서 쉽게 발아하여 많은 소생자를 형성하였다. U. maydis 동포자로부터 소생자 형성의 최적배지는 corn meal broth였고, carrot broth와 potato-dextrose broth의 순으로 좋았다. 소생자 형성에 가장 적합한 조건은 온도 28~3$0^{\circ}C$, pH5~7이었다. 소생자 형성은 암조건에서 보다 좋았다.

• The Korean Journal of Community Living Science
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• v.24 no.3
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• pp.277-287
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• 2013

This study was undertaken to evaluate the change of major nutrient components in boiled broth of anchovy, fish paste, sea tangle, and radish subjected to the boiling processing. The crude protein, fat, ash, and carbohydrates in anchovy boiled broth were 0.1%, 0.04%, 0.1%, and 0% respectively as against 0.04%, 0.1%, 0.2%, and 0.4% in fish paste boiled broth. The protein content in the anchovy boiled broth, the fat and carbohydrate in the fish paste boiled broth, and the ash in the sea tangle boiled broth were high. Major components of the minerals were sodium plus potassium and the boiled broth in anchovy and fish paste had the contents of 19.41 plus 16.19 and 76.77 plus 10.41 mg, respectively. Especially, the potassium in boiled broth of the sea tangle was shown the highest content of 85.94 mg. The Vitamin B1 content in all broth samples were below 0.01 mg per 100 g edible portion. In the case of the B2 content, the anchovy boiled broth had 0.03 mg per 100 g edible portion. On the other hand, the niacin content of the boiled broth on a wet weight basis was detected at an average 0.1 mg. Vit. A, C, tocopherol, and cholesterol was not detected in the boiled broth of any of the subjects. As a result of applying the data of boiled broth in the fish paste soup instead of anchovy and sea tangle which are non-edible, the calcium, dietary fiber, and vitamin A were shown to have a difference of less than 50%.

• Microbiology and Biotechnology Letters
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• v.17 no.6
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• pp.563-567
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• 1989

An alkalophilic bacterium isolated from compost was selected, identified and tested for the production of glutamic acid from ammonium fumarate. The bacterium was closely related to Bacillus brevis. The conditions for glutamic acid production were pH 8.0, 2% fumaric acid, and 0.8% nutrient broth. The mechanism of glutamic acid formation in this strain was postulated as following scheme. (1) Ammonium fumarate longrightarrow Aspartic acid (2) Aspartic acid ＋ $\alpha$-Ketoglutaric acid longrightarrow Glutamic acid + Oxaloacetic acid.