• Preventive Nutrition and Food Science
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• v.20 no.4
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• pp.230-237
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• 2015

This study investigated the impact of microalgal oil (MO) on body weight management in C57BL/6J mice. Obesity was induced for 8 weeks and animals were orally supplemented with the following for 8 additional weeks: beef tallow (BT), corn oil, fish oil (FO), microalgal oil (MO), or none, as a high fat diet control group (HD). A normal control group was fed with a normal diet. After completing the experiment, the FO and MO groups showed significant decreases in body weight gain, epididymal fat pad weights, serum triglycerides, and total cholesterol levels compared to the HD and BT groups. A lower mRNA expression level of lipid anabolic gene and higher levels of lipid catabolic genes were observed in both FO and MO groups. Serum insulin and leptin concentrations were lower in the MO group. These results indicated that microalgal oil has an anti-obesity effect that can combat high fat diet-induced obesity in mice.

• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.637-647
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• 2015

In this study, we attempted to understand signaling pathways behind lipid biosynthesis by employing a chemical genetics approach based on small molecule inhibitors. Specific signaling inhibitors of MAP kinase or modulators of cAMP signaling were selected to evaluate the functional roles of each of the key signaling pathways in three different microalgal species: Chlamydomonas reinhardtii, Chlorella vulgaris, and Haematococcus pluvialis. Our results clearly indicate that cAMP signaling pathways are indeed positively associated with microalgal lipid biosynthesis. In contrast, MAP kinase pathways in three microalgal species are all negatively implicated in both lipid and carotenoid biosynthesis.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.145-150
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• 2022

Microalgae are attracting attention as a resource for the production of biofuels, food nutrients, biochemicals, and bioplastics. Among a wide range of sources of the biomass, microalgae have been highlighted due to relatively easy cultivation, ability to eliminate carbon dioxide, and low culturing cost. Despite the great potential of microalgal biomass as a biological material, the complexity and relatively expensive downstream processes have inhibited the commercial use of microalgae. In this study, we reviewed recent techniques for microalgal drying for the production of microalgal based products. As drying processes comprise the largest portion of microalgae processing cost, an efficient drying technique is key to the utilization of microalgal biomass.

• Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.339-345
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• 2011

Although culture techniques for the abalone Haliotis discus hannai are well known, mass culture of the benthic microalgae that are essential live food for the abalone larvae is still not practiced. This study was conducted to identify the microalgal species suitable for the growth of early larvae of H. discus hannai. The growth and attachment rates of 31 microalgal species were examined. Acrylic plates were used as the substrate. Among the 31 microalgal species, nine showing high growth and attachment rates were selected and tested for their dietary values via factors including settlement, metamorphosis, and survival rates of abalone larvae. Tetraselmis hazeni and Rhaphoneis sp. induced the highest settlement rate (65-69%) in abalone larvae. The metamorphosis rate was highest (57%) in larvae fed Rhaphoneis sp. and was also significantly higher in larvae fed Oscillatoria splendida (29%) and T. hazeni (22%) than in those fed other species. The highest survival rate of the larvae during the 15 days after metamorphosis was 67% in those fed Rhaphoneis sp., followed by T. hazeni (42%) and O. splendida (35%). In conclusion, Rhaphoneis sp. is the most suitable diatom for use as a live food for the culture of early larvae of H. discus hannai. In addition, T. hazeni and O. splendida are also potential species to be further developed and utilized in larval culture.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.1
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• pp.8-15
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• 2007

This study selected the optimal microalgal species for mass culture of a brackish water copepod Paracyclopina nana. Fifteen microalgal species were tested to examine nauplius production and the survival and maturation of brood females. Total and daily nauplius production were highest in P. nana fed Tetraselmis suecica followed Isochrysis galbana, Dunaliella tertiolecta, and Phaeodactylum tricornutum. With a monospecific microalgal diet, the total density was highest with P. nana fed I. galbana, at 63.3 inds./mL. With a mixed microalgal diet, the total density of P. nana fed T. suecica+I. galbana was higher than that fed other mixed diets, although there was no difference between a monospecific diet of I. galbana and a mixed diet of T. suecica+I. galbana. Examining the fatty acid composition of P. nana, the eicosapentaenoic acid (EPA) was highest in P. nana fed T. suecica at 5.4% while the docosahexaenoic acid (DHA) content was highest I. galbana diet at 31.9%. Although no DHA was detected in T. suecica, P. nana fed this microalgal species had a high DHA composition of 24.3%. We suggest that the optimal microalgal species for the mass culture of P. nana is T. suecica which is easy to culture on masse and has a high linolenic acid content.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.3
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• pp.205-218
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• 1992

Trends in the applied microalgal researches were described as those in two separate periods. During the first period (earlie. than 1970) . most researches were oriented to using the whole microalgal cells as feed, food, fertilizer, and agent for the treatment of organic waste water. Since early 1970's (the second period) the number of researches on the production of specific cell metabolites has grown so rapidly. Many researchers endeavored after the very expensive 'natural products' form microalge such as vitamins, amino acids, $\beta-carotene$, phycofluor, pharmaceuticals, biologically active compounds, $H_2$ gas, and deutrated chemicals. On the other hand, the applied microalgal researches in Korea are still in the early stage of developments, and urgent activation of the related researchers is quite important to meet the future needs in the microalgal products. Systems for the management of the management of the microalgal clonal cultures from Korean waters should be established soon, which will support many microalgal researchers in Korea.

• Environmental Engineering Research
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• v.23 no.3
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• pp.229-241
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• 2018

Microalgae are likely to become a part of our everyday diet in the near future as they are considered to be rich in proteins, carbohydrates, and high density lipoproteins. They will play a pivotal role in the food cycle of many people around the globe. Use of microalgae in treating wastewater is also one of the disciplines which are luring researchers as this contributes to a sustainable way of exploiting resources while keeping the environment safe. In addition, microalgal biomass also has the potential to be used as a feedstock for producing biofuel, bio fertilizers, pharmaceuticals, nutraceuticals and other bio-based products. This review presents the different value-added products obtained from microalgal biomass and the applicability of these products commercially.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.6
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• pp.331-337
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• 2003

Unicellular green algae of the genus Dunaliella thrive in extreme environmental conditions such as high salinity, low pH, high irradiance and subzero temperatures. Species of Dunaliella are well known in the alga biotechnological industry and are employed widely for the production of valuable biochemicals, such as carotenoids. Some strains of Dunaliella are cultivated commercially in large outdoor ponds and are harvested to produce dry algal meals, such as polyunsaturated fatty acids and oils for the health food industry, and coloring agents for the food and cosmetic industries. During the past decade, the advances in molecular biology and biochemistry of microalgae, along with the advances in biotechnology of microalgal mass cultivation, enabled this microalga to become a staple of commercial exploitation. In particular, the advent of molecular biology and mutagenesis in Dunaliella has permitted enhancements in the carotenoids content of this green alga, making it more attractive for biotechnological applications. Accordingly, the present review summarizes the recent developments and advances in biotechnology of carotenoid production in Dunaliella.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.268-275
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• 2009

The survival and growth of marine benthic invertebrate larvae such as abalone depend on the nutritional value of micro algae. However, it is difficult to determine the dietary value of the many microalgal species used for food by benthic larvae. Therefore, we tested the benthic copepod, Tigriopus japonicus, which grazes microalgae on substrata in a manner similar to abalone larvae. It also has short generation time and is easy to rear which makes to be easier to examine the dietary value of each micro algal species. We measured the daily production of nauplii from gravid females of T. japonicus fed 26 microalgal species separately. Amino acid and fatty acid content of the micro algae and the copepod was also analyzed. The nauplii production of T. japonicus was the highest (10.7) when they were fed Navicula sp. (B-394) and the lowest (0.8) when they were fed Scrippsiella trochoidea. In Tetraselmis suecica the nauplii production was so high (8.2), which was not significantly different with the diatom group. We determined that Navicula sp. (B-394), Rhaphoneis sp. and T. suecica were good sources of food for T. japonicus. We suggest that a diet of with a mixture of these three micro algal species may be also good for invertebrate larvae such as abalone.

• Journal of Microbiology and Biotechnology
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• v.23 no.10
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• pp.1460-1471
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• 2013

Microalgal biofuel production from wastewater has economic and environmental advantages. This article investigates the lipid production from high chemical oxygen demand (COD) bioethanol wastewater without dilution or additional nutrients, using a newly isolated heterotrophic microalga, Chlorella vulgaris LAM-Q. To enhance lipid accumulation, the combined effects of important operational parameters were studied via response surface methodology. The optimal conditions were found to be temperature of $22.8^{\circ}C$, initial pH of 6.7, and inoculum density of $1.2{\times}10^8cells/ml$. Under these conditions, the lipid productivity reached 195.96 mg/l/d, which was markedly higher than previously reported values in similar systems. According to the fatty acid composition, the obtained lipids were suitable feedstock for biodiesel production. Meanwhile, 61.40% of COD, 51.24% of total nitrogen, and 58.76% of total phosphorus were removed from the bioethanol wastewater during microalgal growth. In addition, 19.17% of the energy contained in the wastewater was transferred to the microalgal biomass in the fermentation process. These findings suggest that C. vulgaris LAM-Q can efficiently produce lipids from high-concentration bioethanol wastewater, and simultaneously performs wastewater treatment.