• Microbiology and Biotechnology Letters
• /
• v.48 no.3
• /
• pp.328-336
• /
• 2020

Parachlorella sp. is an efficient fatty acid producer that can be used in the production of biofuels, feeds, and fertilizers. Microalgae show varying responses to culture conditions, even those within the same species. In this study, growth and fatty acid composition of a newly isolated Parachlorella sp. from the Nakdong river of Korea in different culture media were investigated. The microalga was cultivated in 400 ml bubble column photobioreactors using BG-11, BBM, TAP, and modified TAP (MTAP) media. It was shown that using BBM led to greater fatty acid accumulation (34%), while using TAP medium led to greater biomass productivity (0.34 g/l/day). Composition of the TAP medium was modified to have the N:P ratio of BBM while also varying concentrations of N and P to improve fatty acid productivity. One of the modified TAP media, MTAP-1 (104.8 mgN/l, 135.2 mgP/l, N:P ratio = 0.77), showed the highest fatty acid concentration of 0.69 ± 0.04 g/l, while those from TAP and BBM were 0.48 ± 0.06 g/l and 0.40 ± 0.02 g/l, respectively. The results showed that microalgal fatty acid productivity could be enhanced by changing the N:P ratio and concentrations.

• Journal of Korean Society of Water and Wastewater
• /
• v.23 no.2
• /
• pp.175-180
• /
• 2009

This study was conducted to improve biological degradation efficiency of toluene as a model volatile organic compound (VOC) using yeast Candida tropicalis and to suggest an effective method for bioreactor operation. The yeast strain was immobilized with polyethylene glycol (PEG), alginate, and powdered activated carbon (PAC). The yeast-immobilized polymer media were used as fluidized materials in an airlift bioreactor. Polymer media without PAC were also made and operated in another airlift bioreactor. The two bioreactors showed toluene removal efficiencies ranging 80-96% at loading rates of $10-35 g/m^3-hr$, and the bioreactor containing the polymer media with PAC achieved higher removal efficiency. Protein contents in the liquid phase showed that the bioreactor using the yeast-immobilized polymer media with PAC had a higher rate of microbial growth initially than that without PAC. In addition, the microbial growth rate inside of the polymer media with PAC was five times higher than that without PAC. Consequently, the polymer media containing the yeast strain and PAC could enhance removal efficiencies for VOCs, and the immobilization method improve microbial activity and stability for a long-term operation of biological systems.

• Journal of Korean Biological Nursing Science
• /
• v.11 no.1
• /
• pp.51-58
• /
• 2009

Purpose: It is to verify learning effect of the instructional media on anatomy classes at a nursing college and to develop an alternative instructional media instead of cadaver. Method: Four groups pretest-posttest experimental design were used. One hundred twenty students who attended an Anatomy lecture in September, 2009 were selected After attending the anatomy lecture, the subjects were divided into four group (30 for each group) conveniently. The heart anatomy knowledge level were measured by a self evaluation questionnaire and quiz before and after a different instructional media being applied for each group including making heart shape using colored clay, taking picture of a real heart, sketching the heart model with color pencil and drawing heart presented in the anatomy textbook. Data was analyzed by t-test, ANNOVA test using the SPSS/PC WIN 12 version. Result: A statistically significant differences in the level of heart anatomy knowledge acquirement was noted after four different instructional media being applied, and four different instructional media was effective to the anatomy practice education. However, no difference in statistical post test results was noted among the four groups. Conclusion: It is recommended that further comparative studies on the learning effect between human cadaver practice and different instructional media is necessary.

• Toxicological Research
• /
• v.19 no.4
• /
• pp.325-330
• /
• 2003

The effects of estrogen on apoptosis induced by 2,3,7,8-tetrachlorodibenzo-p-doxin (TCDD) were examined in cultured MCF-7 cells. TCDD stimulated apoptosis and inhibited the expression of bcl-2 gene in MCF-7 cells grown in the media supplemented with 10% fetal bovine serum. However, TCDD failed to induce apoptosis if cells were grown in the media deprived of all estrogen-like compounds. Removal of estrogen-like compounds from the growth media also led to the activation of bcl-2 gene expression in cells treated with TCDD. Combined treatment of estrogen with TCDD abrogated the binding of Aryl hydrocarbon Receptor (AhR)-TCDD complex to Dioxin response element (DRE) of bcl-2 gene leading to the inhibition of bcl-2 gene expression as well as stimulation of apoptosis. The present study suggests that the binding of estrogen receptor (ER)-estrogen complex to the estrogen responsive element (E) interferes with the binding of AhR- TCDD complex to the DRE and inhibits the bcl-2 expression.

• Membrane Journal
• /
• v.22 no.6
• /
• pp.450-460
• /
• 2012

In the submerged membrane-coupled sequencing batch reactor (MSBR) with sponge type media, the effect of media on the removal efficiency and filtration performance were investigated. Dosages of the media in the MSBR were set of 5%, 10%, and 20% based on working volume of reactor. As a control system, the MSBR without media was also operated. The experimental results showed that there was also no difference observed in the removal efficiencies of COD, T-N, and T-P irrespective of the dosages of the media. But TMP (transmembrane pressure) of the MSBR with media increased slowly during the operation time, while that of the MSBR without media increased rapidly at the initial operation. This result was thought that the collisions between flat membrane and moving media gave shear forces which decreased the cake layer on the surface of flat type membrane. Consequently, this study showed that filtration performance of the MSBR with media was greatly enhanced compared with that of the MSBR without media. The MSBR with media suggested in this study can be a good candidate for the wastewater treatment.

• Journal of environmental and Sanitary engineering
• /
• v.12 no.1
• /
• pp.69-75
• /
• 1997

Biological drinking water treatment is widely used in Europe for the removal of ammonia nitrogen and organics. During the last 16 years, the deterioration of the quality of surface waters used to produce drinking water has resulted in the widespread use of ozone-biological treatment in Korea. This study were conducted to determine the effect of media weight and preozonation on the biodegradability enhancement in biological fluidized bed(BFB) using Han river water. When the carbon weight was increased, $NH_{3}-N$ and DOC removal increased, but turbidity and SS removal decreased. To remove turbidity and SS, the bed depth in 40% expansion rate/total bed depth was very important. Preozonation of raw water was not effective in $NH_{3}-N$, but increased in biodegradable organic fraction about 10-30% with 0.425-0.85 mg $O_{3}/mg$ DOC.

• Membrane Journal
• /
• v.26 no.6
• /
• pp.470-479
• /
• 2016

In the advanced treatment of sewage using the submerged membrane-coupled sequencing batch reactor (SMSBR) with media, the effect of media on the filtration performance and removal efficiency were investigated. Dosages of the media in the SMSBR were 10% based on working volume of reactor. As a control system, SMSBR without media and PAC, SMSBR with PAC (10 g/L) only, and SMSBR with media and PAC were also operated. The experimental results showed that there was no big difference observed in the removal efficiencies of COD, T-N, and T-P irrespective of the dosages of the media and PAC. But transmembrane pressure (TMP) of SMSBR with media increased slowly during the operation time, while that of SMSBR without media increased rapidly. Using SMSBR with media, it was possible to operate without the membrane cleaning during the 91 days. Using SMSBR with media only, after 80 days the average removal efficiencies of COD, T-N, and T-P were 95.0, 69.3%, and 51.4%, respectively.

• Applied Biological Chemistry
• /
• v.43 no.3
• /
• pp.202-206
• /
• 2000

Feasibility of microbial culture media using by-product of salt fermented kanary was investigated. Gram negative strain, Escherichia coli, and Gram positive strain, Bacillus subtilis, and bioluminescent Photobacterium Phosphoreum were incubated with kanary by-Product media (KB media). Compared with LB media, KB media had enough carbon source, but lacked nitrogen source and growth factor. When 0.5% of peptone as a nitrogen source and 0.3% of yeast extract as nitrogen and growth factor source were fortified in KB media, the cell population rate was similar to LB media. Also, when 0.5% of yeast extract was fortified to KB media, it showed the same result as in LB media. The price of KB media with fortification of 0.5% peptone and 0.3% yeast extract, and 0.5% of yeast extract is only 46 and 19% of that of LB media, respectively. These results showed that kanary by-Product could be a good and cheaper bacterial culture media if small amount of nitrogen source and growth factor were added.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• v.3 no.2
• /
• pp.97-102
• /
• 2022

In this study, 4,136 pictures posted on a social media platform were analyzed to discover wetlands that are worth visiting to experience our cultural values. Pictures from 300 of the 2,499 listed wetlands have been posted in South Korea. Proximity of a wetland was the most important criterion, regardless of the type of wetlands that were visited. People visited wetlands at the time and season when they were good for recreational activities. Most of the subjects in the pictures were the visitors and natural scenery of a wetland. There was no correlation observed between the wetland conditions and the number of pictures taken by the visitors. Sightseeing and leisure activities are a significant part of various ecosystem services offered by wetlands, but most of the visitors seem to be unaware that the place they have visited is a wetland. Therefore, wetland awareness programs are needed, even for wetlands close to the residential areas that many people have already visited in this study.

• Environmental Analysis Health and Toxicology
• /
• v.19 no.1
• /
• pp.1-24
• /
• 2004

Since dioxins became a serious concern in Korea, a significant number of investigations have been conducted to address diverse issues related to dioxins. However, the results have not been organized for ready access and use. The principal purposes of the work were to ⅰ) provide an archive of dioxin researches in Korea and ⅱ) give an overview of dioxin contamination. The focus of this work was placed on the contamination levels and characteristics concerning the waste incinerators emissions, environmental media, and biological samples(fishes/shellfishes, foods, and human body). Principal component analysis was conducted to identify common and/or unique features and the important variables associated with the congener patterns. From a comprehensive search of academic journals, research and monitoring project reports, dissertations, and periodicals of other forms, a total of 115 counts were found that met the purposes of this study. The contamination levels of various samples were summarized and compared to those reported in foreign literatures. The congener patterns varied largely with environmental media and distinguished particularly by OCDD, 1,2,3,4,6,7,8-HpCDF, and OCDF for the samples within the same media. The proximity to emission sources differentiated the congener patterns in air and soil samples by the fraction of OCDD.