• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.723-731
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• 2015

Microalgae hold promise as producers of sustainable biomass for the production of biofuels and other biomaterials. However, the selection of strains with efficient and robust production of desirable resources remains challenging. In this study, we isolated a green microalga from Korea and analyzed its morphological, molecular, and biochemical characteristics. Microscopic and phylogenetic analyses demonstrated that the isolate could be classified into the genus Chlamydomonas, and we designated the isolate Chlamydomonas sp. KIOST -1. Compositions of protein, lipid, and carbohydrate in the microalgal cells were estimated to be 58.8 ± 0.2%, 22.7 ± 1.2%, and 18.5 ± 1.0%, respectively. Similar to other microalgae belonging to Chlorophyceae, the dominant amino acid and monosaccharide in Chlamydomonas sp. KIOST-1 were glutamic acid and glucose. On the other hand, the proportions of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids clearly differed from other species in the genus Chlamydomonas, and monounsaturated fatty acids accounted for a large portion (41.3%) of the total fatty acids in the isolate. Based on these results, Chlamydomonas sp. KIOST-1 has advantageous characteristics for biomass production.

• Journal of environmental and Sanitary engineering
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• v.10 no.1
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• pp.45-65
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• 1995

Seasonal occurrences and dynamics on the freshwater algae were examined in the upstream of the Yongsan river system with the Kwangju service water area from 1993 to 1994. Three hundred and three taxi were totally collected and composed of 6 classes, 15 orders, 7 suborders, 31 families, 74 genera, 248 species, 48 varieties and 7 forma. Compositions in each algal class were divided in 136 taxi of Chlorophyceae(44.8% ), 109 taxi of Bacillariophyceae(36.0% ), 30 taxa of Cyanophyceae(10.1% ), 21 taxa of Euglenophyceae(6. 9% ),4 taxi of Chrysophyceae(1.3% ) and 3 taxa of Dinophyceae(1.0% ). The occurrence of taxa was a markedly decrease(-62) between summer and autumn, the critically increase(+43) between spring and summer. And also, it was indicated that the high frequency of taxa in summer, but the high standing biomass In winter in spite of low taxi. In general, it has much algal biomass in station 9 and 10, but low in station 4, 5 and 11, relatively. Through this survey, the major dominant taxa in algal biomass, Microcystis aeruginosa, Melosira varians, Synedra ulna and Navicula cryptocephala, they were all above 2.1×10$^{6}$ce11s/1, 13.2% of totals. There are about 10% of new emigrated taxa by season and they showed a remarkable succession. We may suggested that this system was well sustained for the habitat of freshwater algal community with low dominance and high diversity. Twenty three of nuisance algae including of Microcystis aeruginosa, Peridinium willei and Anabaena flos-aquae were distributed as if had low appearance. Of course, many of them were saprobiontic taxa, extraordinary growttung groups depend on organic loading in water system and also it was not showed severe algal blooming phenomenon.

• Korean Journal of Environmental Biology
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• v.28 no.2
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• pp.56-63
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• 2010

In order to clarify the ecological properties of phytoplankton community, the distribution of phytoplankton and the relation of water temperature and size-fractionation measurements were studied from November 2004 to August 2005 in Youngsan River, Korea. A total of 265 phytoplankton species was identified. It consists of 48 genera and 123 species (46%) of Chlorophyceae, 27 genera and 89 species (34%) of Bacillariophyceae, 12 genera and 25 species (9%) of Cyanophyceae, respectively. From size fractionation analysis, nanophytoplankton (2~20 ${\mu}m$) dominated from early spring to early summer, and microphytoplankton (20~200 ${\mu}m$) from summer to winter. The relationship between chl-a and nanophytoplankton showed high correlation coefficient value ($r^2$=0.93) from Najudaegyo site. The correlation coefficient values between water temperature and nanophytoplankton were low except Dongkangdaegyo site which showed high value ($r^2$=0.73).

• Korean Journal of Environmental Biology
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• v.18 no.1
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• pp.95-104
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• 2000

In order to elucidate chatracteristics of water quality and seasonal dynamics of phytoplankton community in Kyungpo lake, the weekly variation of algal population and 11 environmental factors were investigated from March 1998 to February 1999. A total 121 species of phytoplankton belonged to 57 genera, 4 genera 7 species of the Euglenophyceae, 1 genera 2 species of the Chrysophyceae, 2 genera 3 species of the Cryptophyceae, 1 genera 1 species of the Dinophyceae, 6 genera 9 species of the Cyanophyceae, 28 genera 78 species of the Bacillario-phyceae and 15 genera 21 species of the Chlorophyceae, was identified. Cryptomonas sp., Chamydomonas sp., Nitzschia frustulum, Oscillatoria sp., Lyngbya sp, and Dictyosphaerium pulchellum occurred successively as dominant phytoplankton species from March 1998 to February 1999. Density of phytoplankton cell number showed the peak in early April when Chlamydomoas sp. was dominated. The diversity index of phytoplankton community showed low values in the dominating period of Cryptomonas sp. and Chlamydomonas sp. The concentration of chlorophyll a fluctuated between 1.09 and 107.7$\mu\textrm{g}$ㆍ1$^{-1}$. Water temperature, salinity, DO, conduc tivity and SS were ranged 0.5-27.8$^{\circ}C$, 2.8-25.2 ppt, 4.62-19.21 mgO$_2$ㆍ1$^{-1}$, 5.33-34.76 mS/cm and 0.017-0.184 mgㆍ1$^{-1}$, respectively. Annual means of Secchi disc transparency was 36cm and thai of pH value was 8.5. The concentrations of PO$_4$-P was ranged 0.0012-0.077 mgㆍ1$^{-1}$ , and showed high value from August to October. The concentrations of NO$_2$-N, NO$_3$-N and NH$_4$-N was ranged 0.0011-0.1 mgㆍ1$^{-1}$, 0.074-3.33mgㆍ1$^{-1}$ and 0.0024-0.259 mgㆍ1$^{-1}$, respectively. Among environmental factors, water temperature was negatively correlated with DO, salinity and conductivity, DO was positively correlated with salinity and conductivity. Chlorophyll a, one of the indicies of eutropication in lake, was negatively correlated with NH$_4$-N. The cell density of Cryptomonas sp., which was the most dominant species in this lake, was negatively correlated with transparency. [Kyoungpo lake, Phytoplankton, Cryptomonas sp. , Chlamydomonas sp., Seasonal variation].

• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.18-27
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• 1997

The isolation, morphological study and growth characteristics of the algae were investigated from Lake Chuam. The isolated algae were applied the Agal Growth Potential test. The method of isolation and purification of the algae were used to Agar plating(AP), nutrient enrichment(NE), dilution(DI) and micro capillary technique(MC). Total isolated algae were 21 species. They were composed of Cyanophyceae, Dinophyceae, Bacillariophyceae, Euglenophyceae and Chlorophyceae. The numbers of algal strain by isolation technique were highest in dilution(21 species), and those of the rests were showed in order of NE > MC > AP. The sizes of isolated Selenastrum and Scenedesmus were $1.8\pm 1.4 \mu m$, $3.3\pm 0.9 \mu m$ in diameter and $6.4\pm 2.3 \mu m$, $13.6\pm 1.9 \mu m$ in length respectively. The morphology of isolated algae and NIES-collection strain was very similar each other, but the size was smaller isolated algae than that of NIES-collection. The optimum culture condition of isolated Selenastrum and Scenedesmus was about 30$\circ$C(25$\circ$C-35$\circ$C) in temperature and the maximum growth was appeared between 7,000 lux and 8,000 lux in the light intensity. The comparison of $\mu$(specific growth rate) on the concentration of nutrients such as nitrate and phosphate, isolated Selenastrum was appeared maximum it at 1.0 mg $NO_3-N/l$ but NIES-collection strain was showed 95% of maximum it at same nitrate concentration. Maximum g of isolated algae and NIES-collection strain in Scenedesmus onto nitrate concentration were very similar with the result of selenastrum. The specific growth rates of isolated algae and NIES-collection strain on the gradient concentration of phosphate were showed 0.72/day and 0.70/day at 0.02 mg $PO_4-P/l$ in Selenastrum but those of Scenedesmus were appeared 0.61/day and 0.57/day at same concentration $PO_4-P$.

• ALGAE
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• v.20 no.4
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• pp.333-343
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• 2005

Spatial and temporal variations of environmental factors and phytoplankton community were investigated in the three stations of Andong Reservoir in 1997 and 2003. The changes of physico-chemical water quality and phytoplanktonic biomass were higher in 2003 than that of 1997, due to rainfall difference. The concentration of total nitrogen (TN) and total phosphorus (TP) in the reservoir decreased, but total nitrogen fell relatively more between them. TN/TP ratio decreased from 109 to 90 showing no change at the downstream but a big decrease at the midand upstream. Predominant phylum of phytoplankton in Andong Reservoir were six genus that composed to Anabaena, Aphanizomenon and Microcystis of Cyanophyceae, Cosmarium and Scenedesmus of Chlorophyceae and Synedra of Bacillariophyceae, respectively. Among the observed phytoplankton, diatom Synedra occured as the maximum amount of 3,400 cells mL$^{-1}$ even at the above 30°C. Green algae Scenedesmus observed along with Microcystis. It seemed to be compete with Microcystis during the high water temperature period. Although trophic state of Andong Reservoir was decreased, the standing crops of phytoplankton were increased. Moreover bluegreen algae, Aphanizomenon and Microcystis in the region of upstream to midstream and diatom, Synedra in the region of midstream to downstream were increased until to reach the algal bloom, respectively. It seemed necessary to attention the changes of blue-green algae Aphanizomenon, that has an ability of nitrogen fixation.

• Journal of Microbiology and Biotechnology
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• v.27 no.6
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• pp.1039-1052
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• 2017

Endophytic fungi have currently been acknowledged as the most promising source of bioactive compounds for drug discovery, and considerable progress has been made in exploring their diversity, species richness, and bioprospecting. Fungal endophytes from unique environmental settings offer a pool of potentially useful medicinal entities. Owing to the constant stresses imposed on macroalgae by marine environments, it is believed that algae and their associated endophytic symbionts represent a good source of structurally diverse bioactive secondary metabolites. Despite the proven significance of active metabolites of algal endophytes, little have been exploited. This review highlights the latest discoveries in algicolous endophytic research, with particular focus on the bioactive metabolites from algal endophytes. Compounds are classified according to their reported biological activities, like anticancer, antibacterial, antifungal, and antioxidant properties. Present experimental evidence suggests that a majority of the bioactive metabolites were reported from Phaeophyceae followed by Rhodophyceae and Chlorophyceae. An intensive search for newer and more effective bioactive metabolites has generated a treasure trove of publications, and this review partially covers the literature published up to 2016.

• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1276-1282
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• 2010

In traditional mixotrophic cultures of microalgae, all the inorganic nutrients and organic carbon sources are supplied in the medium before inoculation. In this study, however, an alternative approach was adopted in Haematococcus pluvialis Flotow, a microalga capable of growing mixotrophically on sodium acetate (Na-Ac). First, the cells were grown under 75 ${\mu}Mol$ photons $m^{-2}s^{-1}$ phototrophically without Na-Ac until the stationary phase and then exposed to five different light regimes by the addition of Na-Ac (e.g., dark, 20, 40, 75, and 150 ${\mu}Mol$ photons $m^{-2}s^{-1}$). Dry weight (DW), pigments, and especially cell number in alternative mixotrophy (AM) were higher than traditional mixotrophy (TM). Cell number in AM almost doubled up from 21.7 to $42.9{\times}10^4$ cells/ml during 5-day exposure to Na-Ac, whereas the increase was only 1.2-fold in TM. Maximum cell density was reached in 75 ${\mu}Mol$ photons $m^{-2}s^{-1}$ among the light intensities tested. We propose that Na-Ac in TM of H. pluvialis can not be utilized as efficiently as in AM. With this respect, AM has several advantages against TM such as a much higher cell density in a batch culture period and minimized risk of contamination owing to the shorter exposure of cells to organic carbon sources. In consequence, this method may be used for other strains of the species, and even for the other microalgal species able to grow mixotrophically.

• Journal of Environmental Science International
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• v.21 no.11
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• pp.1349-1360
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• 2012

This study presented the phytoplankton communities of the three lakes (Sayeon, Daeam, Hoeya ) using for drinking water in the Ulsan reservoir. The water storage of the Lake Sayeon, Daeam and Hoeya were 25, 13, 21 million ton respectively and most of which were being utilized for industrial and residential purposes. The total precipitation of the Ulsan region in 2010 was 1,162 mm, decreasing 10 % from 1,275 mm of the annual. As for pollutant loads, BOD and TN discharge loads of Daeam was the highest with 3,277 kg/day, 1,931 kg/day and 90 % of them were came from non-point pollutant sources. TP discharge loads showed the highest in the lake Hoeya with 643 kg/day and 97 % of them were came from point sources as household, industry and livestock. We assessed water quality of the lake Sayeon, Daeam and Hoeya using 17 variables. The water quality assessment found that the lake Daeam met the fourth to fifth grade because of high concentration of COD, SS and chlorophyll-a. Eutrophication assessment was conducted by revised Carlson's Index (TSIm, Aizaki) and found that Lake Daeam was more eutrophicated than the other two lakes all the year through as for chlorophyll-a, transparency and the total phosphorus (TP). A total of 95~111 phytoplankton species were identified from the three lake samples. Among them, the largest number of species were Chlorophyceae with 35~51, followed by Bacillariophyceae with 36~45, Cyanophyceae with 9~11, and Cryptophyceae with 6~9 species. The total cell number of phytoplankton was the highest in February (15,254 cells/mL) with Bacillariophyceae in the lake Daeam and the seasonal succession shows that Bacillariophyceae (Stephanodiscus spp.) in the spring, Cyanophyceae (Anabaena spp.) in the summer and the autumn, Bacillariophyceae (Stephanodiscus spp.) in the winter.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.429-434
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• 2005

The dynamics of phytoplankton community after the formatiom of turbidity was assessed at Dam barrage of Lake Imha from May 2003 to July 2004. The maximum turbidity of 1221 NTU during September and October 2003 was well correlated with heavy precipitation caused by Typoon Maemi. A total of 102 phytoplankton taxa was identified and the most abundant phytoplankton group was Bacillariophyceae with 63 taxa, followed by Chlorophyceae with 23 taxa, Cyanophyceae with 9 taxa, 3 taxa each of Synurophyceae and Cryptophyceae and Euglenophyceae with 1 taxon. The total standing crops ranged between 270 indls. $mL^{-1}$ and 4,515 indls. $mL^{-1}$ during the investigation Periods. The three species, Cryptomonas ovata, Cyclotella sp. and Microcystis aeruginosa predominated in sequence after the decrease of turbidity.