• Biotechnology and Bioprocess Engineering:BBE
• /
• 제6권5호
• /
• pp.352-358
• /
• 2001

Because algal cells are so efficient at absorbing incoming light energy, providing more light energy to photobioreactors would simply decrease energy conversion efficiency. Furthermore, the algal biomass productivity in photobioreactor is always proportional to the total photosynthetic rate. In order to optimize the productivity of algal photobioreactors (PBRs), the oxygen production rate should be estimated. Based on a simple model of light penetration depth and algal photosynthesis, the oxygen production rate in high-density microalgal cultures could be calculated. The estimated values and profiles of oxygen production rate by this model were found to be in accordance with the experimental data. Optimal parameters for PBR operations were also calculated using the model.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제5권3호
• /
• pp.186-190
• /
• 2000

It has been reported that flashing light enhances microalgal biomass productivity and overall photosynthetic efficiency. The algal growth kinetics and oxygen production rates under flashing light with various flashing frequencies (5Hz-37 kHz) were compared with those under equivalent continuous light in photobioreactors. A positive flashing light effect was observed with flashing frequencies over 1kHz. The oxygen production rate under conditions of flashing light was slightly higher than that under continuius ligth. The cells under the hight, particularly at higher cell concentrations. When 37kHz flashing light was applied to an LED-based photobioreactor, the concentration was higher than that obtained under continuous light by about 20%. Flashing light may be a reasonable solution to overcome mutual shading, particularly in high-density algal cultures.

• 상하수도학회지
• /
• 제20권1호
• /
• pp.3-11
• /
• 2006

• 한국미생물생명공학회:학술대회논문집
• /
• 한국미생물생명공학회 2003년도 2003 Annual Meeting, BioExhibition and International Symposium
• /
• pp.135-136
• /
• 2003

• 기계와재료
• /
• 제10권3호통권37호
• /
• pp.54-62
• /
• 1998

• 한국수산과학회지
• /
• 제43권3호
• /
• pp.246-253
• /
• 2010

The marine algal flora and community structure were investigated at three sites in Ulsan on the southeast coast of Korea between August 2005 and July 2006. Ninety-one benthic algae species were identified, including 14 Chlorophyta, 21 Phaeophyta, and 56 Rhodophyta species. Of the 91 seaweeds, 19 species were found throughout the survey period. The wet weight biomass ranged from 310.8 to 2,960.4 g $m^{-2}$ during the study period. The maximum biomass was recorded at Sinri, and the minimum was recorded at Daesong. The R/P, C/P and (R+C)/P values reflecting flora characteristics were 2.67, 0.67, and 3.33, respectively. The flora investigated could be classified into six functional groups: coarsely branched (46.2%), thick leathery (22.0%), filamentous (16.5%), Sheet (7.7%), jointed calcareous (4.4%), and crustose (3.3%) forms. A cluster analysis produced two groups that differed meaningfully: one included the site Sinri-summer and the other included the sites Daesong and Jinha.

• 한국수소및신에너지학회논문집
• /
• 제23권4호
• /
• pp.397-403
• /
• 2012

Galactose, an isomer of glucose with an opposite hydroxyl group at the 4-carbon, is a major fermentable sugar in various promising feedstock for hydrogen production including red algal biomass. In this study, hydrogen production characteristics of galactose-glucose mixture were investigated using batch fermentation experiments with heat-treated digester sludge as inoclua. Galactose showed a hydogen yield compatible with glucose. However, more complicated metabolic steps for galactose utilization caused a slower hydrogen production rate. The existence of glucose aggravated the hydrogen production rate, which would result from the regulation of galactose-utilizing enzymes by glucose. Hydrogen produciton rate at galactose to glucose ratio of 8:2 or 6:4 was 67% of the production rate for galactose and 33% for glucose, which could need approximately 1.5 and 3 times longer hydraulic retention time than galacgtose only condition and glucose only condition, respectively, in continuous fermentation. Hydrogen production rate, Hydrogen yield, and organic acid production at galactose to glucose ratio of 8:2 or 6:4 were 0.14 mL H2/mL/hr, 0.78 mol $H_2$/mol sugar, and 11.89 g COD/L, respectively. Galactose-rich biomass could be usable for hydogen fermenation, however, the fermentation time should be allowed enough.

• Journal of Microbiology and Biotechnology
• /
• 제29권9호
• /
• pp.1434-1443
• /
• 2019

Although chemical oxygen demand (COD) is an important issue for wastewater treatment, COD reduction with microalgae has been less studied compared to nitrogen or phosphorus removal. COD removal is not efficient in conventional wastewater treatment using microalgae, because the algae release organic compounds, thereby finally increasing the COD level. This study focused on enhancing COD removal and meeting the effluent standard for discharge by optimizing sludge inoculation timing, which was an important factor in forming a desirable algae/bacteria consortium for more efficient COD removal and higher biomass productivity. Activated sludge has been added to reduce COD in many studies, but its inoculation was done at the start of cultivation. However, when the sludge was added after 3 days of cultivation, at which point the COD concentration started to increase again, the algal growth and biomass productivity were higher than those of the initial sludge inoculation and control (without sludge). Algal and bacterial cell numbers measured by qPCR were also higher with sludge inoculation at 3 days later. In a semi-continuous cultivation system, a hydraulic retention time of 5 days with sludge inoculation resulted in the highest biomass productivity and N/P removal. This study achieved a further improved COD removal than the conventional microalgal wastewater treatment, by introducing bacteria in activated sludge at optimized timing.

• Journal of Plant Biology
• /
• 제34권2호
• /
• pp.165-173
• /
• 1991

본 연구기간 중 인천항 선거내에서 생육하는 해조군집을 1990년 1월부터 12월 사이에 종조성, 우점종 그리고 수직분포를 정성, 정량적인 방법으로 조사하였다. 조사기간 중 6월에 blooming에 의한 큰 교란을 받아 기존하던 해조군집이 완전히 파괴되는 사건이 발생하여 새로운 저층에 대한 군집의 착생과정을 밝힐 수 있는 좋은 계기를 얻게 되었다. 본 조사에서 채집 동정된 해조류는 남조류 18종, 녹조류 13종, 갈조류 6종 그리고 홍조류 8종으로 총 45종이었다. 단위면적당 평균현존량은 교란 전에는 $53.50-188.00\;g-dry\;wt/m^2$ 이였고, 교란 후에도 $0.57-2.62\;g-dry\;wt/m^2$ 이였다. 우점종은 교란전에는 Polysiphonia morrowii와 Ceramium fastigiramosum의 2종이었고, 교란 후 초기 착생종으로 Lyngbya semiplena, Lyngbya lutea 및 Lyngbya rivulariarum 3종으로 대표됨이 밝혀졌다.

• ALGAE
• /
• 제20권3호
• /
• pp.217-224
• /
• 2005

The species composition and biomass of marine algae at the discharge canals of three (Gori, Wolseong and Uljin) nuclear power plants on the east coast of Korea were investigated seasonally from February 1992 to October 2000. As a result, 103-107 species of marine algae were found at the discharge canals during the past nine years. In general, algal communities established at the discharge canals were less diverse than those at the intake canals and control sites. 43 species (6 blue-green, 9 green, 10 brown and 18 red algae) of marine algae occurred more than 1/6 frequency and thus can be categorized as warm tolerant species. Among these, two green (Urospora penicilliformis, Cladophora albida), four brown (Sphacelaria divaricata, S. rigidula, Sargassum coreanum, S. fulvellum) and four red algae (Stylonema alsidii, Bangia atropurpurea, Hypnea charoides, Chondria crassicaulis) are recorded as warm tolerant marine algae for the first time in Korea during this study. Enteromorpha compressa, Padina arborescens, Amphiroa zonata and Ahnfeltiopsis flabelliformis were common species found more than 50% frequency at the discharge canals of all three nuclear power plants investigated. Dominant species in biomass were Padina arborescens and Amphiroa zonata. Results showed that, as a whole, the red algae appeared as predominant algal group at the discharge canals of all three nuclear power plants on the east coast of Korea. However, the biomass proportion of dominant algae at the discharge canals of each nuclear power plant varied over the year during the past nine years.