• Journal of Microbiology and Biotechnology
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• 제29권6호
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• pp.952-961
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• 2019

Chlorella spp. are green algae that are found across wide-ranging habitats from deserts to arctic regions, with various strains having adapted to survive under diverse environmental conditions. In this study, two novel Chlorella strains (ABC-002, ABC-008) were isolated from a freshwater lake in South Korea during the winter season and examined for possible use in the biofuel production process. The comparison of ABC-002 and ABC-008 strains with Chlorella vulgaris UTEX265 under two different temperatures ($10^{\circ}C$, $25^{\circ}C$) revealed their cold-tolerant phenotypes as well as high biomass yields. The maximum quantum yields of UTEX25, ABC-002, and ABC-008 at $10^{\circ}C$ were 0.5594, 0.6747, and 0.7150, respectively, providing evidence of the relatively higher cold-resistance capabilities of these two strains. Furthermore, both the biomass yields and lipid content of the two novel strains were found to be higher than those of UTEX265; the overall lipid productivities of ABC-002 and ABC-008 were 1.7 ~ 2.8 fold and 1.6 ~ 4.2 fold higher compared to that of UTEX265, respectively. Thus, the high biomass and lipid productivity over a wide range of temperatures indicate that C. vulgaris ABC-002 and ABC-008 are promising candidates for applications in biofuel productions via outdoor biomass cultivation.

• Journal of Ecology and Environment
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• 제42권4호
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• pp.240-258
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• 2018

Background: Several investigations carried out from large brackish lagoons in South Korea. However, no studies have yet examined phytoplankton in lagoons that changed to freshwater, such as Cheonjin Lake. The present study examined the algae from Cheonjin Lake. Methods: Samples were collected at monthly inetrvals from May 2017 to April 2018, from the surface layer using a plankton net (mesh size $20{\mu}m$), and sequeezing submerged macrophytes. Microscopic examinations were conducted at a magnification of 200 to 1000x using a Zeiss microscope (Axio Imager. A2), and photographs were taken with an AxioCam HRC camera. Silica-scaled samples of Chrysophyta for SEM were placed on coverglass, air dried, coated with gold, and then examined with a Hitachi SV8220 SEM. Results: A total of 376 taxa from six major algal groups (Chlorophyta, Chrysophyta, Euglenophyta, Cyanophyta, Dinophyta, and Cryptophyta) were identified. Among these algae, 28 taxa of desmids, 9 taxa of Euglenophyceae, 4 taxa of Chlorophyceae, 2 taxa of Chrysophyceae, and 1 taxon of Xanthophyceae are reported for the first time in Korea. A new species, Cosmarium hexagonum sp. nov was described. The phytoplankton communities were characterized by an abundance of Desmids (within Charophyceae) accounted for 148 taxa from 22 genera. Species richness were particularly high in the Autumn. Conclusion: In this study, a total 376 taxa of 148 desmids (Charophyceae), Chlorophyceae (103 taxa), Chrysophyceae (53 taxa), Euglenophyta (49 taxa), Dinophyta (8 taxa), and Cryptophyta (2 taxa) were identified from Cheonjin Lake. Twenty-eight taxa of desmids including a new species (Cosmarium hexagonum sp. nov.), 9 taxa of Euglenophyceae, 4 taxa of Chlorophyceae, 2 taxa of Chrysophyceae, and 1 taxon of Xanthophyceae were newly recorded in Korea.

• ALGAE
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• 제35권4호
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• pp.303-324
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• 2020

Cocconeis coreana and C. sijunghoensis are described as new based on micromorphological and molecular data. C. coreana is represented by five unialgal cultures from four different freshwater bodies, two from North Korea and three from South Korea. C. sijunghoensis is represented by two unialgal cultures from a brackish water body in North Korea. Except for one, all of the strains auxosporulated and showed an almost quadrupling of size in length and width. Morphologically, these species with their two different elliptical valves belong to the Cocconeis placentula group. The raphe valve has striae with uniseriate areolae continuing across a pronounced submarginal hyaline rim to the edge of the valve. The sternum valve has uniseriate dash-like areolae continuously from the valve face until the valve edge. Micromorphologically, these species possess two different open valvocopulae: only the raphe valvocopula has fimbriae; the sternum valvocopula has none. Based on p-distances of currently available DNA sequence data, i.e., rbcL and 18SV4, both species are pronouncedly different from the epitype strain of C. placentula, with C. coreana closest to the published molecular data of the strain UTEX FD23 named C. placentula from Iowa, USA, while C. sijunghoensis is closest but not the same as the published molecular data of strain D36_012, the epitype strain of C. placentula from Berlin, Germany. Based on scanning electron microscope observations, differentiating features are discussed concerning valvocopula fimbriae, central area, areolation of the sternum valve and on the raphe valve especially between the submarginal hyaline rim and edge.

• ALGAE
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• 제37권4호
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• pp.317-329
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• 2022

Carotenoids are effective antioxidants that are found in various photosynthetic organisms. Marine microalgae are an advantageous bioresource for carotenoid production because they do not compete with other crops for freshwater and arable land. This study reports a newly isolated Dunaliella strain from the Geumhong Saltpan on Yeongjong Island, West Sea, Korea. The new strain was isolated and classified as Dunaliella salina through phylogenetic analysis and was named the OH214 strain (Deposit ID: KCTC14434BP). The newly isolated strain can survive in a wide range of NaCl concentrations (0.3-5.0 M NaCl), but grows well in 0.6 to 1.5 M NaCl culture medium. Under high-light conditions (500 ± 10 μmol photons m^-2 s^-1), the cells accumulated three times more β-carotene than under low-light conditions (50 ± 5 μmol photons m^-2 s^-1). The cells accumulated 2.5-fold more β-carotene under nitrogen-deficient (1 mM KNO₃) conditions (3.24 ± 0.36 ㎍ 10⁶ cells^-1) than in nitrogen-sufficient conditions (>5 mM KNO₃). The lutein content under nitrogen-deficient conditions (1.73 ± 0.09 ㎍ 10⁶ cells^-1) was more than 24% higher than that under nitrogen-sufficient conditions. Under the optimized culture condition for carotenoid induction using natural seawater, D. salina OH214 strain produced 7.97 ± 0.09 mg g DCW^-1 of β-carotene and 4.65 ± 0.18 mg g DCW^-1 of lutein, respectively. We propose that this new microalga is a promising strain for the simultaneous production of β-carotene and lutein.

• 생태와환경
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• 제43권3호
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• pp.437-450
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• 2010

국내산 이매패 말조개가 하천의 수질 및 부착조류 성장에 미치는 생태학적 영향을 파악하기 위하여 제작한 인공수로에 부착기질을 설치하고 패류를 도입한 다음 10일 동안 수질 및 조류 현존량 변화를 조사하였다. 인공수로는 아크릴 재질로 유속형성을 위하여 계단식으로 제작하고 부영양호 표층수를 유입하여 일정한 유속으로 통과시켰다. 부착조류 기질로 상용 슬라이드글라스를 패류도입 1주일 전에 각 계단에 40개씩 설치하였다. 패류는 435 ind. $m^{-2}$로 도입하고 10일간 매일 동일한 시간에 수온, pH, 전기전도도, 용존산소, 탁도, 광도, 영양염, 그리고 기철 및 수종의 SS, Chl-$\alpha$, 조류 현존량 등을 각각 분석하였다. 말조개 처리는 수종 탁도(60%), SS(62.5%), Chl-$\alpha$(72.2%), TP(23.9%), 용존산소(19.5%) 농도를 감소시킨 반면, 암모니아 농도는 증가시켰다. 패류처리군의 기질 SS(67%)와 Chl-$\alpha$(89.4%)는 뚜렷하게 증가한 반면 수중의 조류 현존량은 뚜렷하게 감소하였다. 결국 하천의 패류는 수중 유기물의 효과적인 저감을 통하여 투명도 개선을 유도하고 동시에 배출된 영양염 및 배설물은 부착 조류 성장을 촉진할 수 있는 것으로 사료되었다.

• 생태와환경
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• 제40권1호
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• pp.50-60
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• 2007

전국 8곳의 담수역과 1곳의 기중조류 서식지에 대한 미세 녹조류의 채집을 실시하여 녹조식물에 속하는 7속 2종 6변종 2품종의 한국산 미기록 분류군을 추가하였다. 이들은 Scenedesmus속의 1분류군과 Actinotaenium속의 1분류군, 장고말속의 4분류군, 팔장고말속의 1분류군, 오목장고말속의 1분류군, Hyalotheca속의 1분류군과 Teilingia속의 1분류군이 포함되었다. 따라서 현재까지 보고된 한국산 녹조식물은 1강 10목 34과 140속에 속하는 728종 318변종 85품종의 총 1,131분류군으로 정리되었다. 본 연구에서 채집된 10분류군의 한국산 미기록 분류군들은 전 세계에서 이미 보고된 분류군들과 대체로 일치하였으나 3분류군에 있어서는 크기와 형태적인 특징에 있어서 차이점을 나타냈다. Actinotaenium cucurbita var. cucurbita f. rotundatum은 협입부의 폭이 넓은 개체와 함께 좁은 개체가 관찰됨으로써 협입부의 폭에 있어서 변이를 나타냈다. Cosmarium lapponicum var. granulatum과 C. portianum var. orthostichum 그리고 Euastrum denticulatum var. rectangulare은 이미 보고된 분류군들에 비하여 한국산 분류군이 세포의 크기가 작은 것으로 나타났다. Cosmarium lapponicum var. granulatum을 포함한 5분류군은 부영양화 된 수계에 분포하였고, Cosmarium decedens는 산간지방의 습지 또는 하천에 분포하는 것으로 보고되었으나 본 연구에서 기중에도 분포하는 것으로 밝혀졌다.

• 미생물학회지
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• 제38권1호
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• pp.31-37
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• 2002

경북 경산시 에 위치한 남매지 에서 세균군집 의 구조를 fluorescent in situ hybridization(FISH) 방법을 이용하여 분석하였고 아울러 세균군집크기에 영향을 주는 환경요인을 측정하여 그 상관성을 파악하고자 하였다. 담수계에 우점하는 것으로 알려진 proteobacteria($\alpha$.$\beta$.$\gamma$-subclasses)와 글Cytophaga-Flavobacterium (CF) group에 속하는 진정세균군의 연중변화를 정점별로 측정하였다. 총세균수에 대한 각 세균군집 비율은 정점간의 큰 차이 없이 $\alpha$-subclass가 4.0~29.2%,$\beta$-subclass가 1.7~25.8%, $\gamma$-subclass가 1.8~12.8%를, 그리고 CF group은 4.9~36.3%의 군집 비율을 나타냈다. 온도,SS, pH, DOC,질산염, 조류 현존량 등 환경요인과 세균군집 간의 상관관계를 분석한 결과, 총세균수는 수온, DOC,55, eubacteria는 DOC, 녹조류 현존량, $\gamma$-subclass 세균군은 DOC, CF group세 균은 녹조류 현존량과 양의 상관성을 나타낸 반면 $\beta$-subclass는 남세균 . 총 조류 현존량과 음의 상관성을 나타냈다.

• 농약과학회지
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• 제15권1호
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• pp.48-54
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• 2011

국내 주요 6대 하천수역 내 농약 성수기에 검출된 농약의 검출수준을 조사하였고, 수서 생물 3종(조류, 물벼룩, 어류)의 농약 노출에 따른 위해 기능성을 위해 지수(HQ indexes)에 의해 평가하였다. 총 40지점의 모니터링을 실시한 결과, 검출농약은 살균제isoprothiolane, hexaconazole, 살충제 diazinon, chlorpyrifos, prothiofos, 제초제 alachlor, butachlor, molinate의 총 8종으로 확인되었다. 그 중 isoprothiolane이 67.5%의 높은 빈도로 검출되었고, 그 이외의 농약은 15~37.5% 범위의 검출빈도를 나타내었다. 검출빈도는 butachlor >, prothiofos >, ch1orpyrifos >, hexaconazole, molinate > diazinon, alachlor순으로 조사되었다. 전 하천수역에서 수서 생물 3종(조류, 물벼룩, 어류)에 대한 위해 지수가 1.0을 초과하지 않았기 때문에 수 생태계에 대한 위해 가능성이 없는 것으로 평가되었다. 주요 하천수역 내 수서 생물의 위해 가능성에 대한 각 검출 농약의 상대적인 기여도를 평가한 결과, 수서 생물 종별로 다양하게 나타났다. 조류는 butachlor와 molinate성분에 의해, 물벼룩은 chlorpyrifos, diazinon, prothiofos 성분에 의해, 어류는 chlorpyrifos성분에 의해 위해 지수의 기여도가 높게 조사되었다. 본 연구결과는 하천 수계별 농약관리의 우선순위를 선정하는 데 있어 필수자료로 활용될 수 있을 것으로 사료된다.

• 한국환경복원기술학회지
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• 제16권6호
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• pp.119-133
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• 2013

The purpose of this study is to develop riverbed techniques to activating ecological function of hyporheic zone. Hyporheic zone maybe simply defined as an active eco-tone between surface water and groundwater, which facilitates to exchange water, nutrients and aquatic habitat occur in response to variation in discharge and bed geomorphology. The aim of this study is to evaluate the effectiveness of an applied riverbed technique for two years since its installation in the hyporheic zone. The experimental riverbed technique has been implemented on Anyang stream penetrating Anyang city in Gyunggi province. The dimension of the installed structure is 5.0 m in width, 46 m in length. Bottom layer is filled with rip-rap covered with gabion. After the implementation of the technique, the study conducts follow-up monitoring in two years of between 2011 and 2012. The results of follow-up monitoring for two years are as follows:1) In Hydro geomorphic process, the riverbed technique maintains hydraulic stability despite of several flood events in 2011, 2012. 2) After transformation to form pool-and-riffle habitat, for aquatic community composed of freshwater fish, macro invertebrate, and attached algae, the species diversity and population gradually increased. 3) The riverbed technique achieved desired effect on enhancement of ecological function in hyporheic zone.

• 상하수도학회지
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• 제18권2호
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• pp.191-200
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• 2004

DAF process has been designed considering raw water quality characteristics in Korea. Although direct filtration is usually operated, DAF is operated when the freshwater blooms occut or raw water turbidity become high. Pre-sedimentation iS prepared in case when raw water turbidity is very high by rainstorms. A main feature of this plant is that the operation mode can be changed (controlled) based on the characteristics of raw water to optimize the effluent quality and the operation costs. Treatment capacity (surface loading rate) and efficiency of DAF was found to be better than conventional sedimentation process. Moreover, low-density particles (algae and alum flocs) are easily separated while it is difficult to remove in sedimentation. One of the main concerns in adoption of DAF (Dissolved Air-Flotation) process is a high raw water turbidity problem. That is, DAF is not adequate for raw water, which is more turbid than 100NTU. In order to avoid this problem, pre-sedimentation basins are prepared in DAF plant to decrease the turbidity of DAF influent. For simulation of the actual operation, bench and full-scale tests were performed for highly turbid water conditions. Consequently, DAF process coupled with sedimentation is suggested that pre-sedimentation with optimum coagulation prior to DAF would be appropriate.