• The Korean Journal of Food And Nutrition
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• v.13 no.3
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• pp.213-220
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• 2000

본 연구는 찹쌀가루액에 효소처리 및 미생물 접종을 시킴으로써 유과의 제조시 수침과정을 거치지 않고도 유과를 만들수 있는 새로운 방법을 개발하기 위하여 시도되었다. 찹쌀 수침액에 분포된 미샐울은 Bacillus sp와 Lastobacillus spp.로 나타났다. 찹쌀 수침액에 인위적으로 상기 미생물을 배양하였을 대 유과를 제조하기 위한 최적 조건은 3$0^{\circ}C$에서 18시간 이었다. 이때 찹쌀수침액의 PH는 배양시간이 증가함에 따라 증가하였다. 이 찹쌀 수침액에서는 수침시간이 증가함에 따라 $\alpha$-amylase 활성이 증가하여 효소처리된 시료액의 효소 활성화 유사한 경향을 나타내었다. 유과의 팽화도는 효소처리시킨 혼합 접종처리 군을 제외한 모든 처리군에서 28일간 수침한것과 유사하게 나타났다. 경도와 peak수는 모든 처리순에서 28일간 수침시킨 대조군에 비해 유의적으로 더 낮게 나타났다.(P<0.05). 미세구조에서 기공수는 효소처리시킨 단독 접종군이 다른 모든 처리군에 비해 더 많은 기공수를 지니고 있었고 기공의 둘레 및 면적도 유의 적으로 낮은 수치를 나타내었다. .(P<0.05). 따라서, 수침공정을 대폭 단축할 수 있었으며, 향후 미생물 접종을 고려한 효소처리 조건을 정밀 분석한다면 수침공정이 없어도 유과의 품질특성을 나타내는것이 가능할 것으로 보인다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.1035-1040
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• 2016

This study investigated the prevalence of foodborne pathogens and the bacterial community of traditional Doenjang collected from a longevity area in Korea as well as the antagonistic effect of traditional Doenjang isolates against Bacillus cereus to estimate the microbiological safety of traditional Doenjang. Aerobic bacteria showed $10^6{\sim}10^9CFU/g$, whereas coliform bacteria was not detected. Foodborne pathogens were not detected except B. cereus, which was detected in seven samples out of 10 Doenjang samples. A total of 327 isolates were identified from traditional Doenjang. The isolates consisted of Bacillus subtilis 155 (47.4%), Bacillus licheniformis 68 (20.8%), Bacillus amyloliquefaciens 46 (14.1%), and Bacillus pumilus 18 (5.5%). Antagonistic effect against B. cereus was detected in 20 (6.1%) of 327 isolates, which consisted of B. subtilis (12 strains), B. amyloliquefaciens (5 strains), and B. licheniformis (3 strains). The inhibitory zone for the antagonistic effect was 9.0~12.0 mm in diameter. Although a small amount of traditional Doenjang was tested in this study, these results indicated that the potential risk of B. cereus in traditional Doenjang is lower than generally presumed. It is necessary to monitor the antagonistic effect of traditional Doenjang isolates against B. cereus.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.696-701
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• 2011

This study was conducted to investigate impacts of soil properties on microbial distribution in Jeonbuk orchard fields. Soil samples were collected from 110 sites cultivated with different fruit plants. The population of aerobic bacteria and fungi and the content of soil microbial biomass carbon (C) were found to increase with increasing silt content in the soils. Different activity of dehydrogenase was not observed among the different textures of soil. Microbial distribution, amount of microbial biomass C, and dehydrogenase activity in the soils were not significantly different among the topographic sites. However, in pear and grape fruit plant fields, coliform group of bacteria was found in relatively higher population, $133.0{\times}10^3\;CFU\;g^{-1}$ and $107.4{\times}10^3\;CFU\;g^{-1}$, respectively. Microbial groups were simplified and their density was reduced with increasing the cultivation periods of fruit plants. The soil microbial distribution was proportionally correlated with some of soil properties such as soil pH, soil organic matter (SOM) content, and exchangeable Mg content; in particular, the population of Bacillus sp. was proportionally correlated with soil pH and exchangeable Mg content. The amounts of microbial biomass C and the dehydrogenase activity in the soils were significantly correlated with the contents of SOM and exchangeable Ca ion (p<0.01).

• Journal of Life Science
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• v.34 no.7
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• pp.453-464
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• 2024

The fermentation of ganjang is known to be greatly influenced by the microbial communities derived from its primary ingredients, meju and sea salt. This study investigated the effects of changes in meju size on the distribution and correlation of microbial communities in ganjang fermentation, to enhance its fermentation process. Ganjang was prepared using whole meju and meju divided into thirds, and samples were collected at 7-day intervals over a period of 28 days for microbial community analysis based on 16S rRNA gene sequencing. At the genus level, during fermentation, ganjang made with whole meju exhibited a dominance of Chromohalobacter (day 7), Pediococcus (day 14), Bacillus (day 21), and Pediococcus (day 28), whereas ganjang made with meju divided into thirds consistently showed a Pediococcus predominance over the 28 days. Beta-diversity analysis of microbial communities in ganjang with different meju sizes revealed significant separation of microbial communities at fermentation days 7 and 14 but not at days 21 and 28 across all experimental groups. The linear discriminant analysis effect size (LEfSe) was determined to identify biomarkers contributing to microbial community differences at days 7 and 14, showing that on day 7, potentially halophilic microbes such as Gammaproteobacteria, Firmicutes, Oceanospirillales, Halomonadaceae, Bacilli, and Chromohalobacter were prominent, whereas on day 14, lactic acid bacteria such as Pediococcus acidilactici, Lactobacillaceae, Pediococcus, Bacilli, Leuconostocaceae, and Weissella were predominant. Furthermore, correlation analysis of microbial communities at the genus and species levels revealed differences in correlation patterns between meju sizes, suggesting that meju size may influence microbial interactions within ganjang.

• Food Science and Preservation
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• v.13 no.2
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• pp.246-251
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• 2006

Organic compost is a useful fertilizer for organic farming. However, it poses a microbiological hazard to the farm produce because most of the compose are originated from excrementitious matters of domestic animals. Irradiation was performed to improve microbiological safety of organic compost and the effectiveness of gamma-irradiation for inactivating Salmonella typhimurium and E. coli was investigated. Total aerobic bacteria and coliform bacteria in 16 produce or commercial compose were ranged from $10^5\;to\;10^7\;CFU/mL\;and\;0\;to\;10^3\;CFU/mL$, respectively. All coliform bacteria in the composts were eliminated by irradiation at 5 kGy, while about $10^2\;CFU/mL$ of total aerobic bacteria survived up to 10 kGy of irradiation. In the inoculation test the test organisms (inoculated at $10^7\;CFU/mL$) were eliminated by irradiation at 3 kGy. $D_{10}$ values of inoculated Salmonella typhimurium and E. coli in the compost were $0.4{\pm}0.05\;and\;0.39{\pm}0.03kGy$. It was considered that $3{\sim}5kGy$ of gamma irradiation was effective for radicidation (radiation sterilization of pathogenic microbes) of organic fertilizer.

• Journal of Life Science
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• v.17 no.10
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• pp.1374-1380
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• 2007

The development of polymerase chain reaction (PCR) technology has the potential to solve for isolating pathogenic microorganisms from environmental samples than traditional plate counting methods. We have been detected pathogenic bacteria from raw water and water treatment process in Busan metropolitan city by PCR method. According to the result of survey from July 2004 to October 2005, 80 out of 92(87.0%) were positive for bacterial pathogens in raw water samples and positive rate of Shigella spp., Yersinia spp., Salmonella spp. and Legionella spp. were 46.2%, 40.7%, 17.6% and 9.9%, respectively. Pathogenic bacteria in raw water was mainly distributed through the lately Autumn to the winter and more highly detected Maeri than Mulgum region. During the period of survey in water treatment process, Shigella spp. was highly detected but all of bacterial pathogens were entirely removed after in post-ozonation step. These suggest that waters supplied in Busan metropolitan city may be safe against the pathogenic bacteria.

• The Journal of Engineering Geology
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• v.23 no.1
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• pp.37-46
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• 2013

Leakage of leachate from animal carcass disposal is a significant issue because disease can easily spread to humans and other livestock. In this study, we analyzed the physicochemical properties of leachate and tested for the presence of aerobic bacteria in leachate using molecular biology methods, for 16 animal carcass disposals in the first stage (after burial for 5 months). Leachate physicochemical analysis revealed higher total coliforms, TOC, $NH^{4+}$, and $NO^{3-}$ concentrations compared with previously published data. In most leachate samples, the concentrations of $NH^{4+}$ and $NO^{3-}$ exceeded the Korean guideline values for drinking water. In 16S rRNA sequence analysis of the distribution of leachate under aerobic conditions, Bacillus pumilus, Lysinibacillus sphaericus, and B. sphaericus were observed with high frequency, whereas no food-poisoning-related bacteria such as B. cereus or Salmonella were detected. The present findings improve our knowledge of the transport of leachate from animal carcass disposal sites through geologic media, and are useful in risk analysis and for subsequent studies.

• Korean Journal of Microbiology
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• v.31 no.1
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• pp.85-92
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• 1993

To investigate the eutrophication process and pollution characteristics in Paldang Lake, Korea, water and sediment samples were analysed during July 1986~June 1987. The transparency, chlorophyll-a concentration, dissolved oxygen concentration and biochemical oxygen demand in Paldang Lake ranged 0.5~3 m, 3-17 ${\mu}gI^{-1}$, 7.2~12.3 ppm and 0.5~2.3 ppm, respectively. Heterotrophic bacterial number fluctuated seasonally between $3.0{\times}10^{3}/ml and 5.0{\times}10^{5}/ml$ in the water column and between $2{\times}10^{6} and 1{\times}10^{8}$ in the I g dry sediment. Water turbulence and water quality of up-stream seem to play important roles for determining the water quality in Paldang Lake particularly where the hydraulic retention time is so short as about 5 days. The present water quality in Paldang Lake according to the criteria of lake water quality was shown to be between mesotrophic and eutrophic state by secchi depth(O.5 ~ 3 m) and chlorophyll-a concentration (3~17 ${\mu}gI^{-1}$). The distribution of coliform bacteria showed that the pollution was mainly due to the human activities in this area and it is needed to establish countmeasurements for the problems.

• The Journal of the Petrological Society of Korea
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• v.24 no.4
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• pp.291-305
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• 2015

Microbialites are defined as rocks formed by microbial organisms. After their first appearance around 3.5 billion years ago, microbialites occur in various depositional environments throughout geological periods. Microbial organisms form microbialites by trapping and binding detrital sediments and/or precipitating carbonate cements, resulting in formation of various microstructures and mesostructures. Four major types of microbialites are distinguished based on their mesostructures: stromatolite, thrombolite, dendrolite, and leiolite. In the geological records, occurrences of microbialites are influenced by calcium carbonate saturation of seawater and interaction of microbialites with metazoans. Stromatolites mainly flourished during the Precambrian, and diminished as level of atmospheric carbon dioxide declined. On the other hand, thrombolites, mainly formed by calcified microbes, began to flourish from the Neoproterozoic. As metazoans diversified in the Phanerozoic, proportion of the microbialites within sedimentary record declined. Since then, microbialites only occasionally flourished during the Phanerozoic, such as shortly after mass-extinction events. In the Korean Peninsula, microbialites occur in the Neoproterozoic Sangwon System, the Early Paleozoic Joseon Supergroup, and the Cretaceous Gyeongsang Supergroup, which form different shapes according to their age and depositional environments. By performing detailed studies on these Korean microbialites, it is possible to understand how microbes affected geological records and sedimentary environments, as well as their interaction with other organisms.

• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.38-45
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• 2006

Ecological characteristics of microbial populations inhabiting heavy metal polluted soil were investigated. The samples were collected from 293 sites around an factory and industry at Gyeoungsangbuk-do. We measured the contents of seven heavy metal elements (Cd, Cu, As, Hg, Pb, $Cr^{6+}$, CN), seven sites have been seriously contaminated by mercury and chrome. A quantitative evaluation of microbial populations in mercury and chrome contaminated soil was examined by using plate count method. Bacterial numbers in polluted soil samples ranged from $7.4X10^5\;to\;9.3X10^7\;cfu\;g^{-1}$, about $10\sim100$ fold less than the count for the unpolluted soil. Moulds were not detected in chrome polluted soil. The log values of actinomycetes of each contaminated soil samples were log ranged from 6.18 to 7.52. The ratio of actinomycetes was similar to unpolluted soil. The investigation showed actinomycetes to be the major microbial population inhabiting the mercury and chrome polluted soil. Thirty-one isolates among the total isolates were examined for antibacterial activity. These isolates were identified based on a phylogenetic analysis using 16S rRNA gene nucleotide sequences, they were categorized in three major phylogenetic groups, belong to the Streptomyces (6 strains), Saccharopolyspora (3 strains), Nocardiodes (1 strain). On the phylogenetic tree, the clade consisting of five isolates were distantly related to all of the established Streptomycetes genera, indicating the possibility as members of new species.