• ALGAE
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• 제28권1호
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• pp.111-119
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• 2013

Marine microalgae are a promising source of organisms that can be cultured and targeted to isolate the broad spectrum of functional metabolites. In this study, two species of cyanobacteria, Chlorella ovalis Butcher and Nannchloropsis oculata Droop, one species of bacillariophyta, Phaeoductylum tricornutum Bohlin, and one species of Dinophyceae, Amphidinium carterae (Hulburt) were cultured and biomasses used to evaluate the proximate comical compositions. Among the determined proximate chemical compositions of the cultured marine microalgae, the highest content of crude proteins and lipids were exhibited in P. tricornutum and A. carterae, respectively. Solvent-solvent partition chromatography was subjected to fractionate each of the cultured species and separated n-hexane, chloroform, ethyl acetate, and aqueous fractions. Nitric oxide production inhibitory level (%) and cytotoxicity effect on lipo-polysaccharide-induced RAW 264.7 macrophages were performed to determine the anti-inflammatory activity. N. oculata hexane and chloroform fractions showed significantly the strongest anti-inflammatory activity at $6.25{\mu}g\;mL^{-1}$ concentration. The cancer cell growth inhibition (%) was determined on three different cell lines including HL-60 (a human promyelocytic leukemia cell line), A549 (a human lung carcinoma cell line), and B16F10 (a mouse melanoma cell line), respectively. Among the extracts, C. ovalis ethyl acetate and A. carterae chloroform fractions suppressed the growth of HL-60 cells significantly at 25 and $50{\mu}g\;mL^{-1}$ concentrations. Thus, the cultured marine microalgae solvent extracts may have potentiality to isolate pharmacologically active metabolites further using advance chromatographic steps. Hence, the cultured marine microalgae can be described as a good candidate for the future therapeutic uses.

• 한국정밀공학회지
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• 제28권2호
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• pp.154-167
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• 2011

Recently, microalgae have been focused on potential biomass for bio-diesel and biorefinery process. The aim of this paper is to review the biorefinery process including biodesel using microalgae as a microreactor. The state-of-the-art of biodiesel and biorefinery research such as extraction and reaction process as well as byproducts utilization is described. In addition, we suggest possibility for develop bioactive substances and their industrial products from byproducts of microalgae massively obtained after bio-diesel extraction.

• 한국해양바이오학회지
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• 제5권4호
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• pp.40-45
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• 2011

Microalgae are one of the major, sustaining components of ecosystem processes and are responsible for biogeochemical reactions that drive our climate changes. Despite this, many marine microalgae are poorly described and little is known of their abundance and distribution along the coastal areas of Sooyoung Bay, Busan, South Korea. The present study has been conducted from November, 2011 to August, 2009 with the objective to provide an overview of the taxonomy diversity and abundance of microalgae along the coastal areas of the Sooyoung Bay. Water samples were collected from different sites, which were located by using a GPS tracker. Chlorophyll fluorescence of the water samples were measured by using ToxY-PAM dual-channel yield analyzer. The chlorophyll fluorescence values were relatively higher during the spring and summer and even in the region near to the sea port. Similarly the abundance of microalgae was higher near the port but diversity index had lower values. The temperature and pH values were same at all the sites. However, only the temperature varied during the sampling period, with higher values during summer and lower in winter. From the preliminary results, the following class of microalgae were found; Bacillariophyceae, Dinophyceae, Silicoflagellate and Cryptophyceae. With a future ongoing work, microalgae are being isolated to establish single cell culture and for identification using light microscopic observations, photography and molecular approaches.

• 한국해양바이오학회지
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• 제12권1호
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• pp.40-49
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• 2020

This article emphasized the physiological characteristics of the selected marine microalgal strains obtained from the culture collection of the National Marine Biodiversity Institute of Korea (MABIK). Therefore, in this study, 13 different marine microalgal strains belonging to the phylum Chlorophyta were analyzed for the composition of fatty acids, elements, photosynthetic pigments, and monosaccharides, as well as the lipid and protein contents. The results presented that the primary fatty acids were palmitic (C_16:0), palmitoleic (C_16:1 n-7), stearic (C_18:0), oleic (C_18:1 n-9), linoleic (C_18:2 n-6), and α-linolenic (ALA, C_18:3 n-3) acid in the evaluated microalgae. The lipid contents of heterotrophically grown strains ranged from 15.1% to 20.4%. The calorific values of the strains were between 17.4 MJ kg^-1 and 21.3 MJ kg^-1. The major monosaccharides were galactose, glucose, and mannose, while the primary photosynthetic pigments were chlorophyll-a (Chla), chlorophyll-b (Chlb), and lutein, respectively. Based on the results, the microalgal strains showed high potentials in the use of microalgae-based technologies to produce biochemicals, food, and renewable fuels as they are rich in sustainable sources of high-value bio-compounds, such as antioxidants, carbohydrates, and fatty acids.

• 한국해양바이오학회지
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• 제11권2호
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• pp.81-88
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• 2019

In this study, effects of nitrogen (N) and phosphorus (P) starvation on the cell growth and fatty acid (FA) production of newly isolated freshwater microalgae were investigated. The microalgae were identified as Chlorella sp. and Parachlorella sp. through 18S rRNA sequencing. Optimal culture temperature and light intensity were investigated using a high-throughput photobioreator, and the result was validated in 0.5 L bubble column photobioreactors using BG-11 without NaNO₃ and/or K₂HPO₄. Under nutrient starvation conditions, total FA contents of the microalgae were significantly changed rather than FA composition. Starvation of both N and P was most effective for increasing FA contents in Parachlorella sp (24.4±0.1%) whereas highest FA contents (42.6±1.8%) was achieved when only P was starved in Chlorella sp. among tested conditions. These results suggest an effective strategy for increasing FA production from microalgae using appropriate nutrient starvation.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2000년도 춘계수산관련학회 공동학술대회발표요지집
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• pp.487-488
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• 2000

Genomic DNA was isolated from the marine microalgae representing genetic characteristics and genomic polymorphisms by polymerase chain reaction amplification of DNA as arbitrary primers. The electrophoretc analysis of PCR-RAPD products showed hig levels of variation between different genus and little variation between different species. Outer of these primers, 6 generated 248 highly reproducible RAPD markers, producing almost seven polymorphic bands per primers. The degree of similarity frequency between Chaetoceros gracilis and Chaetoceros calcitrans species showed 90％ as calculated by sharing analysis. The RAPD polymorphism generated by this primer may be used as a genetic marker for genus or species identification in important marine microalgae. (omitted)

• ALGAE
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• 제25권1호
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• pp.45-56
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• 2010

In this study, we assessed the antioxidant properties of tidal pool microalgae, Halochlorococcum porphyrae and Oltamannsiellopsis unicellularis, from Jeju Island, Korea. Specifically, the antioxidant activity of fractions isolated from 80% methanol extract, and digests produced from five proteases and carbohydrases, were investigated. Almost all the fractions and the 80% methanol extract exhibited higher effects on 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging. The ethyl acetate fraction showed the highest superoxide anion scavenging activity, while both n-hexane and chloroform fractions exhibited higher $H_2O_2$ scavenging activity. Among the enzymatic digests from H. porphyrae and O. unicellularis, all the digests exhibited remarkable DPPH scavenging activities. In nitric oxide inhibition, all the digests recorded significantly higher effects than those of the commercial antioxidants (p < 0.05). Flavozyme and Neutrase digests from H. porphyrae, and Termamyl and Alcalase digests from O. unicellularis, showed significant effects in metal chelating. Lipid peroxidation was significantly inhibited in the ethyl acetate fraction, in the Celluclast and Protamex digests from H. porphyrae, and in the chloroform fraction from O. unicellularis. These findings suggest that the two tidal pool microalgae tested in this study are rich in potential antioxidative compounds, the specific properties of which can be considered for use in the food and pharmaceutical industries.

• Fisheries and Aquatic Sciences
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• 제13권1호
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• pp.18-25
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• 2010

Interest in plant-derived food additives has increased recently, with efforts to identify natural antioxidant sources to replace synthetic antioxidants. This study evaluated the antioxidant effects of organic solvent fractions of 80% methanol extracts from Pediastrum duplex and Dactylococcopsis fascicularis microalgae. Among the solvent fractions tested, the ethyl acetate and n-hexane fractions from P duplex effectively scavenged 79.8% and 74.5% of DPPH free radicals, respectively. The chloroform fraction from D. fascicularis showed the strongest $H_2O_2$ scavenging ability (49.7%). The greatest scavenging of hydroxyl radicals (73.1%) was exhibited by the 80% methanol extract from P duplex. Aqueous residue and ethyl acetate fraction from P duplex provided the strongest nitric oxide scavenging (57.7%) and metal chelating effect (82.1%), respectively. Chloroform and ethyl acetate fractions from P duplex and n-hexane fraction from D. fascicularis exhibited significantly greater inhibition of lipid peroxidation than the commercial antioxidants. These results suggested that P duplex and D. fascicularis microalgae having potential anti oxidative compounds with various properties could be utilized in the food and pharmaceutical industries.

• 수산해양교육연구
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• 제29권2호
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• pp.552-559
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• 2017

To assess the effect of LED lights on marine microalgae growth in the laboatory, Tetraselmis suecica, Chaetoceros simplex and Isochrysis galbana were cultured under $20{\pm}1^{\circ}C$, Walne's medium and aeration using 3.6 L glass vessels. The LED light sources were Blue, Red, Blue+Red, CoolWhite and WarmWhite. The experiments were conducted three times. The density of microalgae was shown as the counted number of cells per day, and the specific growth rate was calculated by using the density. The statistical analysis was performed by analysis of variance using the SPSS 20.0 program. T. suecica culture was the highest density under the Blue LED light source, so the light source was the most effective for the growth of this alga. C. simplex and I. galbana culture had the highest density under the Blue+Red LED light source, therefore this light source was the most effective for the growth of these algae. The result of analysis of variance showed significant between groups.

• 한국해양바이오학회지
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• 제11권2호
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• pp.52-61
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• 2019

Over the past few decades, microalgae-based biotechnology conjugated with innovative CRISPR/Cas9-mediated genetic engineering has been attracted much attention for the cost-effective and eco-friendly value-added compounds production. However, the discharge of reproducible living modified organism (LMO) into environmental condition potentially causes serious problem in aquatic environment, and thus it is essential to assess potential environmental risk for human health. Accordingly, in this study, we monitored discharged genetically modified microalgae (GMM) near the research complex which is located in Daejeon, South Korea. After testing samples obtained from 6 points of near streams, several green-colored microalgal colonies were detected under hygromicin-containing agar plate. By identification of selection marker genes, the GMM was not detected from all the samples. For the lab-scale environmental risk assessment of GMM, acute toxicity test using rotifer Brachionus calcyflorus was performed by feeding GMM. After feeding, there was no significant difference in mortality between WT and transformant Chlamydomonas reinhardtii. According to further analysis of horizontal transfer of green fluorescence protein (GFP)-coding gene after 24 h of incubation in synthetic freshwater, we concluded that the GFP-expressed gene not transferred into predator. However, further risk assessments and construction of standard methods including prolonged toxicity test are required for the accurate ecological risk assessment.