• Research in Plant Disease
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• 제17권1호
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• pp.38-43
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• 2011

Almost 10~30% of vegetables were discarded by the spoilage from farms to tables. After harvest, vegetables are often spoiled by a wide variety of microorganisms including many bacterial and fungal species. This investigation was conducted to extent the knowledge of relationship the spoilage of vegetables and the diversity of microbes. The total aerobic bacterial numbers in fresh lettuce, perilla leaf, and chicory were $2.6{\sim}2.7{\times}10^6$, $4.6{\times}10^5$, $1.2{\times}10^6\;CFU/g$ of fresh weight, respectively. The most common bacterial species were Pseudomonas spp., Alysiella spp., and Burkholderia spp., and other 18 more genera were involved in. After one week of incubation of those vegetables at $28^{\circ}C$, the microbial diversity had been changed. The total aerobic bacterial numbers increased to $1.1{\sim}4.6{\times}10^8$, $4.9{\times}10^7$, and $7.6{\times}10^8\;CFU/g$ of fresh weight for lettuce, perilla leaf, and chicory that is about $10^2$ times increased bacterial numbers than that before spoilage. However, the diversity of microbes isolated had been simplified and fewer bacterial species had been isolated. The most bacterial population (~48%) was taken up by Pseudomonas spp., and followed by Arthrobacter spp. and Bacillus spp. The spoilage activity of individual bacterial isolates had been tested using axenic lettuce plants. Among tested isolates, Pseudomonas fluorescence and Pantoea agglomerans caused severe spoilage on lettuce.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제26권5호
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• pp.446-457
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• 1993

Monthly distribution of marine bacteria and phytoplankton in Suyeong Bay were investigated with laboratory experiment of dominant algal species and bacterial flora. During the periods of study, the highest density of phytoplankton and bacteria occurred in May with the number of $3.3{\times}10^6cells/l$ and $1.93{\times}10^8cells/ml$, respectively. 10 genera of bacteria and 22 genera of phytoplankton were isolated and identified. In May when phytoplankton bloom occurred, dominant species of bacteria were Acinetobacter calcoaceticus($29.1\%$) and Bacillus subtilis($22.9\%$), and dominant species of phytoplankton were Chaetoceros spp.($62.8\%$) and Skeletonema spp. ($19.4\%$). Pseudomonas spp., which was the most abundant bacterial species during the study periods, were rapidly decreased in May. In laboratory studies of culturing bacteria and phytoplankton isloated in May, the growth of Pseudomonas vesicularis seems to be influenced by the concentrations of excretion matter of Chaetoceros spp. To examine the result colsely, the problem of pure isolation for phytoplankton must be solved and more experimental process have to be conducted.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.952-964
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• 2005

The diesel-degrading activities of biofilms sampled from petroleum-contaminated groundwaters in urban subway drainage systems were examined in liquid cultures, and the microbial populations of the biofilms were characterized by denaturing gel gradient electrophoresis (DGGE) and 16S rDNA sequence analysis. Biofilm samples derived from two sites (19 K and 20 K) at subway Station N and Station I could degrade around $80\%$ of applied diesel within 20 and 40 days, respectively, at $15^{\circ}C$, and these results were strongly correlated with the growth patterns of the biofilms. The closest phylogenetic neighbor of a dominant component in the 19 K biofilm was Thiothrix fructosivorans strain Q ($100\%$ similarity). Four dominant strains in the 20 K biofilm were closely related to Thiothrix fructosivorans strain Q ($100\%$ similarity), Thiothrix sp. CC-5 ($100\%$ similarity), Sphaerotilus sp. IF14 ($99\%$ similarity), and Cytophaga-Flexibacter-Bacterioides (CFB) group bacterium RW262 ($98\%$ similarity). Three dominant members in the Station I biofilms were very similar to uncultured Cytophagales clone CRE-PA82 ($91\%$ similarity), Pseudomonas sp. WDL5 ($97\%$ similarity), and uncultured CFB group bacterium LCK-64 ($94\%$ similarity). The microbial components of the biofilms differed depending on the sampling site. This is the first report on the isolation of clones highly similar to Thiothrix fructosivorans and Thiothrix sp. from biofilms in petroleum-polluted groundwaters, and the first evidence that these organisms may play major roles in petroleum degradation and/or biofilm-development.

• Korean Journal of Microbiology
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• 제39권2호
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• pp.108-113
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• 2003

Diesel oil-degrading bacterial strains were isolated from diesel oil contaminated soil and called HS series (HS1, HS2 and HS3). These strains were identified as Acinetobacter sp. (HS1) and Pseudomonas sp. (HS2 and HS3) based on Biolog test, cellular fatty acid composition, and 16S rDNA sequence analysis. These strains were coltivated in liquid minimal media containing 2% diesel oil, and diesel oil-degrading activity was measured. As result, all strains degraded over 70% of total diesel oil. But PAH (polycyclic aromatic hydrocarbon)- and pris- tane-degrading rate of these strain was below 20％ of total PAH and pristane. The HS 1 strain showed highest hydrophobicity and low emulsifying activity among the experimental strains and high diesel oil-degrading activity. From the above-mentioned result, microcosm experiment was performed with the HS1 strain. The HS1 strain showed a degrading activity of over 80% of total diesel oil in microcosm test. And microbial activity was correlated to diesel oil-degrading activity. Therefore, it is suggested that the HS1 strains could be effectively used for the bioremediation for diesel oil.

• Microbiology and Biotechnology Letters
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• 제26권6호
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• pp.523-528
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• 1998

We isolated microorganism secreting antimicrobial substance from tomato and identified as Enterococcus faecium. This substance was completely inactivated by pretense treatment and retained activity after catalase treatment. This result indicated that the antimicrobial activity of this substance was due to proteinaceous substance known as bacteriocin. The bacteriocin inhibited growth of Gram positive bacteria, such as Listeria monocytogenes, Leuconostoc mesenteroides, Lactobacillus plantarum, Streptococcus agalactiae, Streptococcus pyrogenes, and Gram negative bacteria, such as Pseudomonas aeruginosa. Purification of the bacteriocin was achieved by ethanol precipitation, ion exchange chromatography on CM Sepharose CL-6B, and gel filtration on Sephacryl S-100 HR. After these purification steps, the specific activity of the bacteriocin was increased 35.8 fold compared with culture broth. Purified bacteriocin was shown single band on SDS-PAGE and molecular weight was estimated 51 kDa. The residual activity of this bacteriocin was 3.3% at 10$0^{\circ}C$ for 60 min, and this bacteriocin was stable at pH 2~7.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.513-516
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• 2001

This study was to develop of efficient microbial agent for malodor removal. Total ten strains of beneficial bacteria Bacillus sp., Pseudomonas sp., and photosynthetic bacteria were isolated and identified on the basis of their morphological and biochemical characteristics. The enzyme activities such as amylase, protease, lipase and cellulase of bacteria cells were measured. Furthennore, effective formulation procedure 、 ,vas developed with nutrient additive, stabilizing agent and mineral materix. For preparation of microbial agent, developing of formulation technique was very helpful for incresing the cell survival rate.

• Microbiology and Biotechnology Letters
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• 제25권6호
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• pp.552-559
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• 1997

Fe (III) impurities in clay could be microbially removed by inhabitant dissimilatory Fe (III) reducing microorganisms. Insoluble Fe (III) in clay particles was leached out as soluble reductive form, Fe (II). The microorganisms removed from 10 to 45% of the initial Fe (III) when each sugar was supplemented to be in ranges of 1 - 5 % (w/w; sugar/clay). The microorganisms reduced 2.1 - 12.8 mol of Fe (III) per 100 mol of carbon in sugars metabolized when sugars such as glucose, maltose, and sucrose were used as sole carbon source. Bacillus sp. IRB-W and Pseudomonas sp. IRB-Y were isolated from the enrichment culture of the clay. The isolates were considered to participate in metabolizing organic compounds to fermentative intermediates with relatively little Fe (III) reduction at initial Fe (III) reduction process. By the microbial treatment, the whiteness of the clay was increased form 63.20 to 79.64, whereas the redness was obviously decreased form 13.47 to 3.55. This treatment did not cause any unfavorable modifications in mineralogical compositions of the clay.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.952-958
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• 2004

Of 23 psychrotrophic bacteria isolated from the west Pacific deep-sea sediments, 19 were assigned to the $\gamma$-Proteobacteria, 3 to the <$\beta$-Proteobacteria, and 1 to the Gram-positive bacteria, as determined by their 16S rDNA sequences. Ten psychrotrophs, affiliated to the Psychrobacter, Pseudoalteromonas, and Pseudomonas genera in the $\gamma$-Proteobacteria group, were screened for lipolytic bacteria. The majority of the lipolytic isolates had growth temperatures between 4-$30^\circ{C}$, and all of them were neutrophilic, aerobic, or facultatively anaerobic, and some were able to produce multiple kinds of ectohydrolytic enzymes. The deep-sea strains Psychrobacter sp. wp37 and Pseudoalteromonas sp. wp27 were chosen for further lipase production analysis. Both strains had the highest lipase production when grown at 10 to $20^\circ{C}$; their highest lipase production occurred at the late-exponential growth stage; and the majority of the enzymes were excreted to the outside of the cells. Lipases from both strains had the same optimal reaction temperature and pH (20-$30^\circ{C}$, pH 7-8) and could retain about 60% of their highest activity at $4^\circ{C}$. Furthermore, SDS-PAGE and an in-gel activity test showed that they had the same high molecular mass of about 85 kDa.

• Microbiology and Biotechnology Letters
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• 제24권6호
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• pp.647-651
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• 1996

The development of an enrichment method for the rapid and effective identification of Salmonella spp. in sewage or food was studied. As a growth factor for Salmonella, 10 mM cyclic adenosine monophosphate (cAMP) in trypticase soy broth with 0.6% yeast extract (TSBYE) increased cell number five-folds and 0.6% yeast extract in selenite broth increased cell number ten-folds of control. Bile salts in selenite broth was tested for the selection of S. enteritidis in a mixture with Staphylococcus aureus, Pseudomonas aeruginosa, Lactobacillus plantarum and Escherichia coli. The latter four strains were effectively inhibited at 0.1% bile salt. A two-step culture method was used to enrich Salmonella spp.; a primary-enrichment and secondary- enrichment culture. At a primary-enrichment step, selenite broth with 0.6% yeast extract and 10 mM cAMP was used, and at a secondary-enrichment step, 0.1% bile salt was additionally used. Culture times of a primary- enrichment and a secondary-enrichment step were 8 hr and 6 hr, respectively. In this procedure, cell number increased from 10$^{0.3}$ to 10$^{8.5}$ with inhibition of other strains within 14 hr. In the case of an initial cell concentrarion as low as 10$^{-2}$ cfu/ml, a cell number increased to 10$^{7}$ cfu/ml by using a 10 hr primary-enrichment and 6 hr secondary-enrichment procedure.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제48권2호
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• pp.113-119
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• 2003

Soybean sprout pathogenic bacteria were isolated from the large, deep containers of a commercial factory. Over a period of one year, 40 pathogenic-like bacteria were isolated among a total of 732 isolates. In addition to bacteria previously reported to be associated with rotting, such as Pseudomonas putida and Erwinia carotovora, several other genera were also identified: Acinetobacter spp., Chryseobacterium spp., Klebsiella sp., Pantoea agglomerans, Bacillus sp. Fatty acid methyl ester (FAME) analysis using the Microbial ID (MIDI) system, and 16s rRNA sequence analysis, yielded identical results, confirming the identities of these microorganisms. Several types of selective media were not good for identification and determination of population structure in commercial environments, as colony type was not specific to the genus. There was no dominant bacterium, and we were not able to find the main bacterium responsible for soybean spout rot. Even though we did not identify a major target for controlling rot or screening for resistant cultivars, the results of this study indicated that bacterial rot of soybean sprout is endemic. In addition, it emerged that factory epidemics in summer are not caused by the bacteria isolated in this study.