• 생명과학회지
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• 제8권2호
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• pp.173-180
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• 1998

미세 조류의 항균성 탐색을 위해 베를린 공대 생물공학 연구실에서 좀 균주을 분양받아 독일 현지 연구실에서 연구를 행하였다. 6종의 미세 조류로부터 항균성 시험 시료응 획득하기위해 먼저 배양데 따른 미세 죠류 배양액의 변화를 pH와 균제량으로 관찰하였고, 이를 토대로 시험 시료를 대주중식기와 정기기 두 구간으로 나누어 채취하였다. 얻어진 시료를 균체와 균체 상층액으로 분리하여 각족 용매를 이용하여 분획을 행하여 4-7종의 획분들 얻었거 이들이 가지는 항균 활성을 시험하였다. BGA(blue green algae) 4종류 중에서 Lsp(lyngbya sp.)와 Tsp(Tetraselmis sp.)에서 항균활성이 관측되었는데, 특히 균체외 상층액의 dthyl acetate 추출 획분이 서균과 특히 곰팡이에 대해 강력한 항균 활성이 있는 것으로 확인되었고, 그뢰 2종의 BGA 와 2종의 규조류(diatoms)에서는 항균 활성 획분이 확인되지 않았다.

• 한국재료학회지
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• 제28권7호
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• pp.376-380
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• 2018

Microalgae produce not only lipids for biodiesel production but also valuable biochemicals which are often accumulated under cellular stress mediated by certain chemicals. While the microcarriers for the application of drug delivery systems for animal cells are widely studied, their applications into microalgal research or biorefinery are rarely investigated. Here we develope dual-functional magnetic microcapsules which work not only as flocculants for microalgal harvesting but also potentially as microcarriers for the controlled release of target chemicals stimulating microalgae to enhance the accumulation of valuable chemicals. Magnetic microcapsules are synthesized by layer-by-layer(LbL) coating of PSS-PDDA on $Fe_3O_4$ nanoparticle-embedded $CaCO_3$ microparticles followed by removing $CaCO_3$ sacrificial templates. The positively charged magnetic microcapsules flocculate microalgae by electrostatic interaction which are sequentially collected by the magnetophoretic separation. The microcapsules with a polycationic outer layer provide efficient binding sites for negatively charged microalgae and by that means are further utilized as a chemical-delivery and flocculation system for microalgal research and biorefineries.

• 한국물환경학회지
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• 제30권4호
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• pp.386-393
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• 2014

The aim of this study was to investigate the nutrient removal and biomass productivity in the wastewater using MMBR (Microalgae Membrane Bioreactor). MMBR process was combined OPPBR (Optical Panel Photobioreactor) and MBR (Membrane bioreactor). The OPPBR and MBR were operated 3 days and 9h HRT (Hydraulic retention time), respectively, using microalgae as Chlorella vulgaris. The obtained result indicated that the biomass productivity of 0.498 g/L/d with light transmittance of 92% at a 305 mm depth in the OPPBR was achieved. The total consumption of BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) in the MMBR were found to be 97.56% and 96.06%, respectively. Additionally, the removal of TN, $NO_3-N$, TP and $PO_4-P$ were 94.94%, 91.04%, 99.54% and 93.06% in MMBR, respectively. These results indicated that the MMBR process was highly effective for COD, BOD and nutrient removal when compared to the separate OPPBR or MBR process. The MMBR process was effective for nutrient removal and biomass productivity and can be applied to treat wastewater in sewage treatment plant.

• Korean Chemical Engineering Research
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• 제56권5호
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• pp.773-778
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• 2018

In-situ transesterification of microalgae lipids using microwave irradiation has potential to simplify and accelerate biodiesel production, as it minimizes production cost and reaction time by direct transesterification of microalgae into biodiesel with microwave as a heating source. This study was conducted to research the effect of microwave irradiation with in-situ transesterification of microalgae under base catalyst condition. The process variables (reaction time, solvent ratio, microwave power) were studied using 2% of catalyst concentration. The maximum yield of FAME was obtained at about 32.18% at the reaction time of 30 min with biomass-methanol ratio 1:12 (w/v) and microwave power of 450 W. The GC MS analysis obtained that the main component of FAME from microalgal oils (or lipids) was palmitic acid, stearic acid and oleic acid. The results show that microwaves can be used as a heating source to synthesize biodiesel from microalgae in terms of major components resulting.

• 한국미생물·생명공학회지
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• 제49권2호
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• pp.167-173
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• 2021

Reactive oxygen species (ROS) disrupt the cellular redox balance, exert cytotoxic effects, and consequently promote the development of various diseases in humans. Previous studies have reported that antioxidants counteract the adverse effects of ROS. Several studies examine the whitening effects of various agents based on their ability to inhibit tyrosinase activity. Tyrosinase is a critical enzyme involved in the synthesis of melanin, which protects the skin against radiation. Various agents exhibiting antioxidant and tyrosinase inhibitory activities have been synthesized. However, these synthetic drugs are associated with toxicity, decreased safety, and poor skin penetration in vivo, which has limited the clinical application of synthetic drugs. This study examined the antioxidant and tyrosinase inhibitory activities of some microalgae. The methanol, dichloromethane, and ethyl acetate extracts of four microalgal species (Tetraselmis tetrathele, Dunaliella tertiolecta, Platymonas sp., and Chaetoceros simplex) were prepared. The physiological and whitening effects of microalgal extracts were investigated by measuring the antioxidant and tyrosinase inhibitory activities. The ethyl acetate extract of D. tertiolecta exhibited the highest antioxidant and tyrosinase inhibitory activities. Future studies must focus on examining the whitening effects of microalgae on cell lines to facilitate the development of microalga-based therapeutics for skin diseases, functional health foods, and whitening agents. Thus, microalgae have potential applications in the pharmaceutical, food, and cosmetic industries.

• Journal of Microbiology and Biotechnology
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• 제32권7호
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• pp.862-868
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• 2022

Microalgae are photosynthetic cyanobacteria and eukaryotic microorganisms, mainly living in the water. In agriculture, numerous studies have been conducted to utilize microalgae as a biostimulant resource. Scenedesmus has been known to be one such microalga that can promote plant growth by secretion of auxin or cytokinin hormone analogs. However, no research has been performed on the effect of microalgae treatment on plant microbiota communities. This study was conducted to investigate the mode of action of microalgae as biostimulants in a plant microbiota perspective by using Scenedesmus sp. CHK0059 (also known as species Chlorella fusca), which has been well documented as a biostimulant for strawberries. The strawberry cultivar Keumsil was bred with Seolhyang and Maehyang as the parent cultivars. Using these three cultivars, microbiota communities were evaluated for changes in structural composition according to the CHK0059 treatment. CHK0059-treated Seolhyang, and CHK0059-untreated Maehyang were similar in microbial diversity in the endosphere. From a microbiota community perspective, the diversity change showed that CHK0059 was affected by the characteristics of the host. Conversely, when CHK0059 treatment was applied, populations of Streptomyces and Actinospica were observed in the crown endosphere.

• Journal of Microbiology and Biotechnology
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• 제32권11호
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• pp.1357-1372
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• 2022

Heavy reliance on fossil fuels has been associated with increased climate disasters. As an alternative, microalgae have been proposed as an effective agent for biomass production. Several advantages of microalgae include faster growth, usage of non-arable land, recovery of nutrients from wastewater, efficient CO₂ capture, and high amount of biomolecules that are valuable for humans. Microalgae Chlorella spp. are a large group of eukaryotic, photosynthetic, unicellular microorganisms with high adaptability to environmental variations. Over the past decades, Chlorella has been used for the large-scale production of biomass. In addition, Chlorella has been actively used in various food industries for improving human health because of its antioxidant, antidiabetic, and immunomodulatory functions. However, the major restrictions in microalgal biofuel technology are the cost-consuming cultivation, processing, and lipid extraction processes. Therefore, various trials have been performed to enhance the biomass productivity and the lipid contents of Chlorella cells. This study provides a comprehensive review of lipid enhancement strategies mainly published in the last five years and aimed at regulating carbon sources, nutrients, stresses, and expression of exogenous genes to improve biomass production and lipid synthesis.

• ALGAE
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• 제39권3호
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• pp.163-176
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• 2024

Some marine microalgae and cyanobacteria form mutualistic symbioses with diverse invertebrates, particularly cnidarians. Among microalgae, dinoflagellates in the family Symbiodiniaceae are the most well-known symbiotic partners of jellyfish and corals. However, the symbioses involving other dinoflagellate families, nano- and micro-flagellates, diatoms, and cyanobacteria with cnidarians are not well understood. As an initial step, it is essential to explore the survival of these microorganisms inside cnidarians. We monitored the survival of eight microalgal species (nine strains) and one cyanobacterium species every day for seven days after injecting each into the medusa of the moon jellyfish Aurelia aurita. The dinoflagellates Effrenium voratum (free-living [FL] and living-in-coral strains), Cladocopium infistulum, Prorocentrum cordatum, Prorocentrum koreanum, Symbiodinium microadriaticum, the prasinophyte Tetraselmis suecica, the chlorophyte Dunaliella salina, and the raphidophyte Heterosigma akashiwo survived inside the medusa, while the cyanobacterium Synechococcus sp. was not detected. Additionally, E. voratum (FL) survived within the medusa for 60 days and gradually spread to adjacent areas, indicating potential for artificially established symbiosis. The results of this study provide a basis for artificial symbiosis between microalgae and invertebrates.

• 한국습지학회지
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• 제20권4호
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• pp.363-369
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• 2018

최근 환경 문제로 대두되고 있는 것 중 하나는 대기 중 $CO_2$의 증가로 인한 기후변화이다. 이에 대한 영향으로 생태계가 변화하고 있으며, 다양한 환경문제가 발생되고 있다. 이로 인해 전 세계적으로 $CO_2$ 저감을 위한 다양한 연구들이 수행중이며, 이 중 미세조류를 이용한 $CO_2$ 저감 방안은 환경 친화적인 방법이라 할 수 있다. 그러나 미세조류를 이용한 $CO_2$ 저감 방안은 대부분 단일 종을 대상으로 하고 있으며, 자연 하천을 대상으로 한 미세조류의 $CO_2$ 고정 효율에 대한 연구는 전무한 실정이다. 그러므로 본 연구는 우리나라 하천 내 존재하는 미세조류들을 파악하고, 미세조류의 생장특성을 분석하여 최적의 배양조건을 도출 하였다. 그리고 $CO_2$ 농도와 주입 속도에 따른 미세조류의 biomass와 클로로필 a의 변화를 분석하여 자연 하천 내 존재하는 미세조류의 $CO_2$ 고정효율에 대해 연구하고자 하였다. 섬강 내 존재하는 미세조류를 배양하여 동정한 결과 6종의 우점종(Ankistrodesmus falcatus, Scenedesmus intermedius, Selenodictyum sp., Xanthidium apiculatum var. laeve, Cosmarium pseudoquinarium, Dictyosphaerium pulchellum)이 관찰되었으며, 이 종들은 모두 녹조류에 해당하였다. 한편 이산화탄소 농도 구배(5% $CO_2$, 10% $CO_2$, 15%$CO_2$, 대기조건의 가스 0.038% $CO_2$)와 유속(0.25, 0.5LPM)이 다른 가스를 주입하여 미세조류의 biomass와 클로로필 a의 변화를 살펴본 결과 이산화탄소의 농도가 증가할수록 biomass와 클로로필 a가 증가하였으며, 같은 이산화탄소 농도에서는 유속이 더 빠른 곳에서 미세조류의 biomass와 클로로필 a의 양이 더 증가하였다. 또한 미세조류에 고정화된 이산화탄소의 양은 주입되는 가스의 유속이 빠를수록 고정되는 이산화탄소의 양이 더 높아지는 경향을 보였다. 본 연구는 기존의 단일 종에서 행해지는 연구가 아닌 하천 전체의 미세조류를 대상으로 수행한 연구이며, 하천 내 존재하는 미세조류의 이산화탄소 고정을 위한 최적의 조건을 도출하고, 하천 내 존재하는 미세조류로부터 고정화된 이산화탄소의 양을 정량화하여 향후 이산화탄소 감축을 위한 정책을 위한 기초자료에 이용할 수 있다는 것에 큰 의의가 있다.