• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.2
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• pp.79-89
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• 1995

Changes of microbial activity and physicochemical environment during composting of papermill sludge(PMS) in the pilot plant equipped with an agitated bed reactor were monitored for establishing the efficient composting system. Microbial activity determined as the evolution of $CO_2$ increased for the first 10 days after introduction of PMS to the reactor and decreased thereafter. Population changes of microorganisms in the reactor-PMS were not typical as in windrow system. The ratio of thermophilic bacteria to mesophilic bacteria, however, increased slowly even 23 days after introduction. Temperature of PMS increased rapidly from the first day and reached $62^{\circ}C$ at 7 days after introduction and decreased slowly thereafter. The acidity of PMS was pH 6.8 initially, increased to pH 8.0 after 7 days and decreased to pH 7.4 after 23 days. Redox potential(Eh) of PMS was -320mV at the beginning of composting, but it was increased with time to reach -15mV after 23 days composting. However, Eh of PMS pre-sterilized before measurement was average 50mV, regardless of composting periods indicating the major role of microorganisms during composting process. Water content of PMS was 67% initially and decreased to about 50% after 23 days composting in the reactor. Less than 13 days-old compost inhibited growth of radish in the container mixture with bed soil. Based on statistical analysis of microbial and physicochemical parameters of PMS during composting, an equation was developed for determining compost maturity. A number of experiments using various organic wastes are required before application of the formular to the practical use.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.342-347
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• 2004

A bacterial strain YC4963 with antifungal activity against Colletotrichum orbiculare, a causal organism of cucumber anthracnose was isolated from the rhizosphere soil of Siegesbeckia pubescens Makino in Korea. Based on physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, the bac­terial strain was identified as Pseudomonas aurantiaca. The bacteria also inhibited mycelial growth of several plant fungal pathogens such as Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani on PDA and 0.1 TSA media. The antifungal activity was found from the culture filtrate of this isolate and the active compound was quantitatively bound to XAD adsorption resin. The antibiotic compound was purified and identified as phenazine-l-carboxylic acid on the basis of combined spectral and chemical analyses data. This is the first report on the production of phenazine-l-carboxylic acid by Pseudomonas aurantiaca.

• Journal of agriculture & life science
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• v.46 no.3
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• pp.97-108
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• 2012

Physical, chemical and biological hazards of strawberry farms at the cultivation stage were analyzed to establish the GAP(Good Agricultural Practice) system. Samples were collected from the plants, cultivation environments(water, soil and air), and personal hygiene (hand, glove, and clothes) of three strawberry farms(A, B, and C) and were tested to analyze physical, chemical (heavy metals and pesticide residues), and biological(sanitary indications and foodborne pathogens) hazards. Physical hazards such as insects and pieces of metal and glass were found in the strawberry farms and can be potential bow for strawberry products. Heavy metal and pesticide residue as chemical hazards were detected at levels lower than the regulation limit. In case of biological hazards, total bacteria and coliform were detected at the levels of 1.6~7.3 and 1.3~5.6 log CFU/g, leaf, mL, hand or $100cm^2$. However, Escherichia coli was not detected in all samples. Bacillus cereus and Staphylococuus aureus were detected at levels of ${\leq}$ 1.1~6.1 log CFU and 4.7~5.4 log CFU/g, mL, hand or $100cm^2$, whereas Listeria monocytogenes, E. coli O157 and Salmonella spp. were not detected in all samples. This study demonstrates that various harzards were in strawberry farms at the growing stage. Therefore proper management such as GAP is needed to prevent the occurrence of food poisoning associated with the hazards revealed in this study.

• Korean Journal of Veterinary Research
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• v.49 no.3
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• pp.257-263
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• 2009

Bovine mastitis is an important disease causing serious economic loss in dairy production and food poison in public health. Escherichia coli and Staphylococcus aureus are the major causative agents of bovine mastitis. These bacteria were found in milk and environmental condition such as feces, water, soil and so on. Bovine mastitis causative micro-organisms can survive in 1-2 weeks in feces and bed complexes. Low level of percentage of water content (PWC) of feces and bed complexes can reduce the spreading of bovine mastitis incidence from environmental contamination. In this study, we developed the fecal dehydrating system and determined the elimination rates of bovine mastitis causative agent from feces and bed complexes. To develop the fecal dehydrating system, the screw pressurized dehydrating system was used and the maximum rate of dehydrating was reached to 52% PWC using 90% PWC (wet base) of fecal and bed complexes. The elimination rates of the dehydrating system for E. coli and S. aureus were reached at 41.19 $\pm$ 7.84% to 62.55 $\pm$ 8.71% in various percentages of PWC of feces and bed complexes (80, 85 and 90%). These results suggested that the application of fecal dehydrating system would reduce the exposure of dairy cattle to bovine mastitis causing agents contaminated feces and bed complexes, and can be used for environmental bovine mastitis control avoiding misuse or abuse of chemical disinfectants and antibiotics in dairy farm.

• Journal of Life Science
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• v.21 no.10
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• pp.1473-1480
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• 2011

Perchlorate ($ClO_4^-$) is a contaminant found in surface water and soil/ground water. Microbial removal of perchlorate is the method of choice since microorganisms can reduce perchlorate into harmless end-products. Such microorganisms require an electron donor to reduce perchlorate. Conventional perchlorate-removal techniques employ heterotrophic perchlorate-reducing bacteria that use organic compounds as electron donors to reduce perchlorate. Since continuous removal of perchlorate requires a continuous supply of organic compounds, heterotrophic perchlorate removal is an expensive process. Feasibility of autotrophic perchlorate-removal using elemental sulfur granules and activated sludge was examined in this study. Granular sulfur is relatively inexpensive and activated sludge is easily available from wastewater treatment plants. Batch tests showed that activated sludge microorganisms could successfully degrade perchlorate in the presence of granular sulfur as an electron donor. Perchlorate biodegradation was confirmed by molar yield of $Cl^-$ as the perchlorate was degraded. Scanning electron microscope revealed that rod-shaped microorganisms on the surface of sulfur particles were used for the autotrophic perchlorate-removal, suggesting that sulfur particles could serve as supporting media for the formation of biofilm as well. DGGE analyses revealed that microbial profile of the inoculum (activated sludge) was different from that of the biofilm sample obtained from enrichment culture that used sulfur particles for $ClO_4^-$-degradation.

• Microbiology and Biotechnology Letters
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• v.39 no.1
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• pp.37-42
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• 2011

I isolated the actinomycete strain KH223 from soil samples collected from the Kye Ryong mountain area. This strain is antagonistic to the multidrug-resistant Acinetobacter baumannii. KH223 was confirmed as belonging to the genus Streptomyces based on the scanning electronmicroscopy(SEM) observations of the diaminopimelicacid(DAP) type and morphological and physiological characteristics. Comparison of the 16S rDNA nucleotide sequences revealed that KH223 has a relationship with Streptomyces galbus. Production of antibiotics by KH223 was most favorable when cultured on a glucose, polypeptone, and yeast extract(PY) medium for 6 days at 27$^{\circ}C$. The supernatant was found to exhibit an antimicrobial effect on various kinds of bacteria and fungi. Particularly, butanol and ethylacetate extracts of KH223 and cyclo(trp-trp) exhibited significant activity against A. baumannii at concentration ranges of 0.8-12.5 ${\mu}g$/mL, 5.0-25 ${\mu}g$/mL and 12.5${\rightarrow}$100 ${\mu}g$/mL, respectively. Moreover, in contrast to cyclo(trp-trp) had shown to activity against Micrococcus luteus JCM 1464 at the concentration of 12.5 ${\mu}g$/mL, the butanol extract of KH223 showed significant activity against Bacillus subtilis IAM 1069 and Micrococcus luteus JCM 1464 at the concentration of 0.4 and 0.8 ${\mu}g$/mL, respectively. These results suggest that KH223 may have a great potential in the production of new antibiotics to combat multidrug-resistant pathogens and further studies may be warranted for the same.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.336-342
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• 2013

Trichloroethylene (TCE) is a widely used substance in commercial and industrial applications, yet it must be removed from the contaminated soil and groundwater environment due to its toxic and carcinogenic nature. We investigated bacterial community structure, dominant bacterial strain, and removal efficiency in a TCE contaminated groundwater treatment system using immobilized carrier. The microbial diversity was determined by the nucleotide sequences of 16S rRNA gene library. The major bacterial population of the contaminated groundwater treatment system was belonging to BTEX degradation bacteria. The bacterial community consisted mainly of one genus of Pseudomonas (Pseudomonas putida group). The domination of Pseudomonas putida group may be caused by high concentration of toluene and TCE. Furthermore, we isolated a toluene and TCE degrading bacterium, named Pseudomonas sp. DHC8, from the immobilized carrier in bioreactor which was designed to remove TCE from the contaminated ground water. Based on the results of morphological and physiological characteristics, and 16S rRNA gene sequence analysis, strain DHC8 was identified as a member of Pseudomonas putida group. When TCE (0.83 mg/L) and toluene (60.61 mg/L) were degraded by this strain, removal efficiencies were 72.3% and 100% for 12.5 h, respectively. Toluene removal rate was 2.89 ${\mu}mol/g$-DCW/h and TCE removal rate was 0.02 ${\mu}mol/g$-DCW/h. These findings will be helpful for maintaining maximum TCE removal efficiency of a reactor for bioremediation of TCE.

• Applied Biological Chemistry
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• v.50 no.4
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• pp.262-267
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• 2007

To access the natural product antibiotics produced by uncultured microorganisms, six cosmid libraries of DNA extracted directly from soil samples (environmental DNA, eDNA) were constructed and screened for the production of antibacterial active molecules. Of the approximately 60,000 clones screened, one antibacterial clone (YS92B) was detected. Ethyl acetate extracts of clone YS92B showed antibacterial activity against various pathogenic bacteria (Listeria monocytogenes, Bacillus subtilis, Pseudomonas syringae, Xanthomonas campestris pv. oryzae, Staphylococcus epidemis). Active constituents from cultures of YS92B were isolated and purified using a bioassay-guided fractionation against B. subtilis through a series of procedures (ethyl acetate extraction, Sephadex LH20 column chromatography, High Performance Liquid Chromatography). NMR (Nuclear Magnetic Resonance) spectral analysis of a major antibacterial active YS92B-VII indicated that it is a lauric acid linked to tyrosine. This report describes the characterization of antibacterially active long chain N-acyl derivatives of tyrosine that are produced by eDNA clones hosted in Escherichia coli from Korean soils.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.332-338
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• 2000

This experiment was conducted to investigate the effects of feeding with MS (miraculous soil-bacteria)-fermented food waste on feeding efficiency and meat quality of mallard. Twenty one heads of 12 weeks-old mallards were fed with three different mixing rates of MS-fermented food waste (0, 20 and 50 %) with 7 replicates. After 6 weeks of feeding, weight gain and feed intake were measured to estimate feeding efficiency, moreover physico-chemical characteristics, amino acids and fatty acids of the fresh slaughtered mallards were analyzed to determine meat quality. The feeding efficiency of 0 % fermented food waste (control) was significantly (p<0.05) higher than other treatments. Water holding capacity and pH were not significantly differed. The color value in lightness of control meat was higher, while in redness was lower than that of the plots mixed with fermented food waste. Total content of amino acids in thigh meat was relatively lower in control, but that in breast meat showed a reverse trend. The amount of unsaturated fatty acids in both thigh and breast meat was the highest in the 50 % mixed plot. Considering economic and environmental aspects for mallard feeding, this results indicated that MS fermented food waste could be a useful resources for mallard feed.

• The Korean Journal of Food And Nutrition
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• v.23 no.4
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• pp.659-663
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• 2010

This research aimed to investigate the quality of conventional salted cabbages. Here, we studied the general characteristics and microbiological aspects of purchased salted cabbage samples from 15 companies. The purchased salted cabbages used a sun-dried salt, but two samples used a mixture of sun-dried salt and processed salt. There were 4 times of washing, 3 steps of washing after automatic washing, and 3 steps of washing after bubble washing as washing methods for the salted cabbages and ground water was used as the washing water. Also, three samples received HACCP certification. The salt contained in the purchased salted cabbages ranged from 0.5% to 2.0%, representing low salted cabbages. The pH of the purchased salted cabbages ranged from 5.32 to 6.47, and hardness ranged from 1,997 g to 3,665 g. Rewashing was necessary before using some salted cabbages due to foreign materials such as insects, soil, etc. Total bacterial counts of the purchased salted cabbages ranged from 3.36 log to 6.06 log and coliform bacteria ranged from below 1 log to 6.05 log, whereas other pathogens were not detected.