• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2000.05a
• /
• pp.294-295
• /
• 2000

양식 어류의 건강 증진을 위한 천연물질 또는 미생물의 개발과 이용에 대한 관심은 점점 높아지는 추세에 있으며, 이것은 양식산업의 친환경적 이미지 부각과 소비자에 대한 양식어의 선호도 증가 등의 장점을 향상시키는데 기여하기 때문이다. 어류의 양식과 관련한 미생물의 이용은 그 중요성에 비해 그다지 많은 연구가 수행 되지 않고 있으며, 어류의 자치어에 대한 먹이생물로서, 또는 어류의 초기먹이생물의 배양 등과 관련한 연구가 중심이 되고 있다(소림, 1966; Okamoto et al., 1988). (중략)

• Korean Journal of Environmental Biology
• /
• v.41 no.1
• /
• pp.89-100
• /
• 2023

We investigated the spatial distribution of heterotrophic bacteria associated with different water masses in the northern East China Sea(ECS) in summer. The surface water masses were divided into the Changjiang Diluted Water (CDW) and high salinity water (HSW). In the CDW region, the concentrations of dissolved inorganic nitrogen (DIN) and chlorophyll-a (Chl-a), and micro Chl-a contribution were high; and bacterial abundance (BA) and ciliate abundance (CA) were also high. In the HSW region with relatively low DIN concentrations, Chl-a concentration and micro Chl-a contribution were low, but pico Chl-a contribution was increased compared to those in the CDW region. BA did not show any significant difference from the CDW region, but CA was decreased. BA showed a positive correlation with Chl-a concentration in the CDW region; however, it did not show a significant correlation with Chl-a concentration in the HSW region. The ratio of bacterial carbon biomass/phytoplankton carbon biomass was exponentially increased with a decrease in the Chl-a concentration. Compared to the past (1990-2000s), the surface phosphate concentrations and the size of dominant phytoplankton have recently decreased in the ECS. Considering this trend of nutrient decrease and miniaturization of the phytoplankton, our results indicate that changes in the strength of the oligotrophic water mass could alter the function of the microbial food web.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.26 no.6
• /
• pp.179-188
• /
• 2023

참달팽이(Koreanohadra koreana)는 환경부에서 지정한 법정보호종(멸종위기 야생생물 II급)이며, 전라남도 신안군 홍도와 하태도에서만 서식하는 한국고유종이다. 반면, 그 동안 참달팽이 지방산에 대한 연구는 진행된 바 없다. 홍도와 하태도를 대상으로 계절, 미소서식처, 지역 차이에 따른 참달팽이의 지방산 구성 변화를 비교하기 위해 분석에 사용한 표본의 개수는 총 99개였다. 실험결과 총 16가지의 지방산이 검출되었으며, 주로 식물질 먹이에서 유래되는 다중불포화지방산(PUFAs)이 53.6%로 가장 높았다. 반면, 동물성 또는 미생물에서 유래하는 단일불포화지방산(MUFAs)은 31.4%, 포화지방산(SFAs)은 15.0%로 상대적으로 적게 검출되었다. 참달팽이의 총 지방산량 변화는 PUFAs의 변화와 가장 강한 상관관계(R²=0.88, p < 0.0001)를 보였다. 계절별로 PUFAs는 봄 (13.20 mg/g)과 여름 (13.08 mg/g)이 가을 (12.06 mg/g)과 겨울 (12.40 mg/g)에 비해 많은 양이 검출되었다. 미소서식처별 PUFAs는 초지대(12.80 mg/g)에서 석회질 지대(12.48 mg/g) 보다 다소 높게 나타났다. 반면, 지역별로 홍도(12.65 mg/g)와 하태도(12.64 mg/g)는 차이가 거의 없었다. PUFAs는 참달팽이의 먹이원을 기반으로 한 서식지의 질을 추적할 수 있는 하나의 지표로서 활용가치가 높을 것으로 기대된다.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.6
• /
• pp.1011-1019
• /
• 2000

The purpose of this study is to examine the basis of design condition of existing treatment processes, namely, Extended Aeration Process, Conventional Activated Process, High Rate Aeration Process and Modified Aeration Process, by clarifying the correlations of influent wastewater concentration, hydraulic retention time, food-to-microorganism ratio and sedimentation of sludge, as well as to ascertain the feasibility of design, regardless of the existing design condition. In particular, this study made a priority investigation of hydraulic retention time and sludge sedimentation, because sludge sedimentation is the main factor$^{1)}$ which determines the operating conditions of existing treatment processes. Therefore, it is generally known that in case exceeds the sphere of design presented for each treatment, sludge bulking may occur. The results of Lesperance's test$^{1)}$, which formed the basis of design, showed the sphere of loading without security of sludge sedimentation, as in Fig. 1. The reason for sludge bulking in a certain condition, as above, is due to failure in application of optimum loading corresponding to each retention time by employing a few operating condition, which proved to be consecutively workable after years of trials and failures by Lesperance, for test conditions. However, the result of this test showed that in case of proper maintenance of loading. sludge sedimentation can be ensured under 120 SVI. Therefore, this study suggested hydraulic retention time and its corresponding optimum loading, and identified the hydraulic retention time as a determinant of sludge sedimentation. And. on the basis of these findings, this study suggested the feasiblity of UHR(Ultra High Rate), a new operating process, exceeding several times the applicable loading value of High Rate Aeration Process under one hour retention time which has not yet applied to the existing treatment processes.

• Korean Journal of Environmental Agriculture
• /
• v.35 no.1
• /
• pp.39-45
• /
• 2016

BACKGROUND: This study aimed to evaluate the combined effects of three components (NPK) of chemical fertilizers with basal application of compost on soil organisms.METHODS AND RESULTS: The soil was treated with five treatments continuously for 15 years: control, PK, NK, NP and NPK. The application of N increased plant growth or biomass, and enhanced organic matter content in the soils. Levels of microbial phospholipid fatty acids (PLFAs) in the soils did not show marked differences among the soils treated with different treatments. However, the principal component analysis showed the changes in the structure of the microbial community in the soil, depending on treatments added. Nitrogen application caused a decrease of pH and an increase of EC in the soils, and these environmental stresses appeared to offset the promoting effect of increased organic matter content on microbial abundance. The abundance of bacterivorous nematodes was the highest in the soils after treating NPK; however, the abundance of fungivorous nematodes was unaffected. There was no significant correlation between the abundances of microbial groups and their feeders. Organic matter content was significantly correlated with the abundance of nematodes in the soils.CONCLUSION: Our results showed that chemical fertilizers affect the soil food chains through both biotic and abiotic factors, and a trophic cascade in the soils may not occur in response to long-term fertilization.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.23 no.2
• /
• pp.47-52
• /
• 2015

A microbial fuel cell (MFC) is a device that can be obtained electricity from a variety of organic through the catalytic reaction of the microorganism. The MFC can be applied to various fields, and research is required to promote the performance of the microbial fuel cell for commercialization. The lower performance of an MFC is due to oxygen reduction at the cathode and the longer time of microbial degradation at anode. The MFC amount of power is sufficient but, in consideration of many factors, as a renewable energy, now commonly power density as compared to Nafion117 it is an ion exchange membrane used is PP (Poly Propylene) from 80 to about 11 fold higher, while reducing the cost to process wastewater is changed to a microporous non-woven fabric of a low cost, it may be energy-friendly environment to generate electricity. All waste, in that it can act as a bait for microorganisms, sustainability of the microbial fuel cell is limitless. The latest research on the optimization and performance of the operating parameters are surveyed and through the SSaM-GG(Smart, Shared, and Mutual- Green Growth) or GG-SSaM(Green Growth - Smart, Shared, and Mutual) as the concept of sustainable development in MFC, the middle indices are developed in this study.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.12
• /
• pp.2239-2245
• /
• 2000

For the treatment of wastewater being discharged in large quantities as in these modern times, qualitative and quantitative concepts should be introduced in consideration of the recycling. In view of a qualitative concept, high rate aeration process is known as the most effective process up to now. However, Lee suggested UHR process showing the superiority over high rate process in treatment rate and quantity. Therefore, this study was performed to investigate the basic sphere of design and treatment quality, such as applicable $BOD_5$-loading and influent wastewater concentration of UHR process, based on Lee's suggestions1). Consequently, this process showed applicable $BOD_5$-loading of $2.2{\sim}7.0kg-BOD_5/kg-MLSS{\cdot}day$, exceeding three times or more of high rate process with maximum applicable loading of $2.25kg-BOD_5/kg-MLSS{\cdot}day$. Meanwhile, with the range of influent wastewater concentration from 200 to 450 mg/L. it showed the treatment rate from 94.7 to 97.3%, it indicated very good condition. In view of quantitative concept of treatment, UHR process is considered an epoch-making treatment process being superior to existing ones.

• Korean Journal of Microbiology
• /
• v.44 no.1
• /
• pp.10-13
• /
• 2008

Endocrine disrupting chemicals (EDCs) are hard to be degraded in nature, and are also accumulated in diverse organisms. They finally give negative effects to human through the food web. White rot fungi which have lignin-degrading enzymes have high potentials for degradation of recalcitrant compounds, and a white rot fungus, Phlebia tremellosa, isolated in Korea show good degrading activity against the endocrine disrupting phthalates. We have isolated a laccase cDNA which was involved in the degradation of EDCs, and constructed a laccase expression vector to use in the genetic transformation of P. tremellosa. The expression vector was stably integrated into the chromosomal DNAs and showed increased laccase activity in transformants. One of transformants showed not only increased degradation of several EDCs but also faster estrogenic decreasing activities generated by the EDCs.

• Korean Journal of Microbiology
• /
• v.45 no.1
• /
• pp.82-85
• /
• 2009

Endocrine disrupting chemicals (EDCs) disturb animal hormonal system even at very low concentrations, and finally give harmful effects to human through the food web. A white rot fungus Phlebia tremellosa isolated in Korea, was reported to have good degrading activity against the endocrine disrupting phthalates. However, this fungus has very low manganese peroxidase (MnP) activity under various culture conditions while laccase and lignin peroxidase activities were high. We have isolated an MnP cDNA from Trametes versicolor which was involved in the degradation of EDCs, and constructed an MnP expression vector to use in the genetic transformation of P. tremellosa in order to get higher MnP producing strains. Many transformants had integrated expression vector in their chromosomal DNAs, and showed increased MnP activity. One of two transformants showed increased degradation of 4 EDCs (70${\sim}$88%) than the wild type (30${\sim}$45% degradation rates), and showed twice better removal of estrogenic activities generated by the EDCs than the wild type.

• Korean journal of applied entomology
• /
• v.46 no.2
• /
• pp.303-311
• /
• 2007

From the course of screening of useful xylanase producing microorganism from a phytophagous longicorn beetle, we isolated an extra-cellular xylanase producing strain, Paenibacillus sp. HY-8 from the intestine of Moechotypa diphysis adult. On the basis of morphological, biochemical and phylogenetic studies of the new isolate was identified as a Paenibacillus species. Production of xylanase in this strain was strongly induced by adding xylan to the growth medium and repressed by glucose or xylose. The highest xylanase production was attained in the M9 media containing 1% yeast extract and 0.5% birchwood xylan when cultured at $25^{\circ}C$ for 24 hrs. HY-8 producing xylanase showed superior hydrolytic activities against various plant source feedstuff than control xylanase produced by Tricoderma sp. at pH 6.0.