• Journal of Microbiology and Biotechnology
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• 제25권1호
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• pp.109-118
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• 2015

Open raceway ponds are cost-efficient for mass cultivation of microalgae compared with photobioreactors. Although low-cost options like wastewater as nutrient source is studied to overcome the commercialization threshold for biodiesel production from microalgae, a cost analysis on the use of wastewater and other incremental increases in productivity has not been elucidated. We determined the effect of using wastewater and wavelength filters on microalgal productivity. Experimental results were then fitted into a model, and cost analysis was performed in comparison with control raceways. Three different microalgal strains, Chlorella vulgaris AG10032, Chlorella sp. JK2, and Scenedesmus sp. JK10, were tested for nutrient removal under different light wavelengths (blue, green, red, and white) using filters in batch cultivation. Blue wavelength showed an average of 27% higher nutrient removal and at least 42% higher chemical oxygen demand removal compared with white light. Naturally, the specific growth rate of microalgae cultivated under blue wavelength was on average 10.8% higher than white wavelength. Similarly, lipid productivity was highest in blue wavelength, at least 46.8% higher than white wavelength, whereas FAME composition revealed a mild increase in oleic and palmitic acid levels. Cost analysis reveals that raceways treating wastewater and using monochromatic wavelength would decrease costs from 2.71 to 0.73 $/kg biomass. We prove that increasing both biomass and lipid productivity is possible through cost-effective approaches, thereby accelerating the commercialization of low-value products from microalgae, like biodiesel.

• The Korean Journal of Malacology
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• 제24권3호
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• pp.189-197
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• 2008

In order to develop the sustainable ecological management, short-necked clams, Ruditapes philippinarum, were collected from Yoengi coast in Tongyoeng, Korea. The growth of the clam was estimated as: $L_f=68.08{\cdot}(1-e^{-0.145(t+0.324)})$ from ring radius composition of shell. Instantaneous co-efficiency of total mortality and natural mortality were calculated as: 0.991/year and 0.494/year, respectively. The age of the clams from the first capture was estimated to be 3.28. The total biomass was estimated to be 212 MT in the fisheries area (6.4 ha). Applied by these parameters, the annual recruit biomass and the current yield per recruit were calculated to be 649.5 individual/$m^2$ and $0.7\;g/m^2$, respectively. The current fishing intensity was much lower for maximum sustainable yield and acceptable biological catch. Although higher yield per recruit could be achieved by increasing fishing intensity, it is favorable to retain the current fishing intensity because of the unique fishing attitude on Yeongi coast in Tongyoeng, Korea.

• Journal of Microbiology and Biotechnology
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• 제22권4호
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• pp.501-509
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• 2012

A 990 bp full-length gene (xynAHJ2) encoding a 329-residue polypeptide (XynAHJ2) with a calculated mass of 38.4 kDa was cloned from Bacillus sp. HJ2 harbored in a saline soil. XynAHJ2 showed no signal peptide, distinct amino acid stretches of glycoside hydrolase (GH) family 10 intracellular endoxylanases, and the highest amino acid sequence identity of 65.3% with the identified GH 10 intracellular mesophilic endoxylanase iM-KRICT PX1-Ps from Paenibacillus sp. HPL-001 (ACJ06666). The recombinant enzyme (rXynAHJ2) was expressed in Escherichia coli and displayed the typical characteristics of low-temperature-active enzyme (exhibiting optimum activity at $35^{\circ}C$, 62% at $20^{\circ}C$, and 38% at $10^{\circ}C$; thermolability at ${\geq}45^{\circ}C$). Compared with the reported GH 10 low-temperature-active endoxylanases, which are all extracellular, rXynAHJ2 showed low amino acid sequence identities (<45%), low homology (different phylogenetic cluster), and difference of structure (decreased amount of total accessible surface area and exposed nonpolar accessible surface area). Compared with the reported GH 10 intracellular endoxylanases, which are all mesophilic and thermophilic, rXynAHJ2 has decreased numbers of arginine residues and salt bridges, and showed resistance to $Ni^{2+}$, $Ca^{2+}$, or EDTA at 10 mM final concentration. The above mechanism of structural adaptation for low-temperature activity of intracellular endoxylanase rXynAHJ2 is different from that of GH 10 extracellular low-temperature-active endoxylanases. This is the first report of the molecular and biochemical characterizations of a novel intracellular low-temperature-active xylanase.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• 제54권3호
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• pp.217-223
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• 2018

Overfishing capacity has become a global issue due to over-exploitation of fisheries resources, which result from excessive fishing intensity since the 1980s. In the case of Korea, the fishing effort has been quantified and used as an quantified index of fishing intensity. Fisheries resources of coastal fisheries in the Korean waters of the East Sea tend to decrease productivity due to deterioration in the quality of ecosystem, which result from the excessive overfishing activities according to the development of fishing gear and engine performance of vessels. In order to manage sustainable and reasonable fisheries resources, it is important to understand the fluctuation of biomass and predict the future biomass. Therefore, in this study, we forecasted biomass in the Korean waters of the East Sea for the next two decades (2017~2036) according to the changes in fishing intensity using four fishing effort scenarios; $f_{current}$, $f_{PY}$, $0.5{\times}f_{current}$ and $1.5{\times}f_{current}$. For forecasting biomass in the Korean waters of the East Sea, parameters such as exploitable carrying capacity (ECC), intrinsic rate of natural increase (r) and catchability (q) estimated by maximum entropy (ME) model was utilized and logistic function was used. In addition, coefficient of variation (CV) by the Jackknife re-sampling method was used for estimation of coefficient of variation about exploitable carrying capacity ($CV_{ECC}$). As a result, future biomass can be fluctuated below the $B_{PY}$ level when the current level of fishing effort in 2016 maintains. The results of this study are expected to be utilized as useful data to suggest direction of establishment of fisheries resources management plan for sustainable use of fisheries resources in the future.

• Korean Chemical Engineering Research
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• 제56권4호
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• pp.453-460
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• 2018

Owing to rising oil prices and anthropogenic global warming, focused attempts are being made toward production of industrially important compounds by using renewable biomass. In this context, algal biomass as third-generation biomass is important because it doesn't compatible with food resource, has high yield, and helps abate greenhouse gases. Here, we investigate whether Undaria has the highest sugar content, which would make it the most suitable biomass for lactic acid production among the four algal biomasses tested. For effective pretreatment of Undaria, the response surface methodology was used. The amount of solid loaded and catalyst concentration were related to the extraction rate of total sugar. Lactic acid was produced by pretreatment of Undaria by using four Lactobacilli, and L. alimentarius and L. brevis were found to be suitable for lactic acid production.

• Journal of the Korean institute of surface engineering
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• 제49권1호
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• pp.14-19
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• 2016

Biomass is a renewable and sustainable source of energy used to create electricity or pressurized steam. In biomass-fueled power plants, wood waste or other waste is burned to produce steam that runs a turbine to make electricity, or that provides heat to industries and homes. Biomass power plants, apart from producing energy, help to reduce the $CO_2$ emission. However, the main problem is the high-temperature corrosion due to fuel corrosivity, especially of the straw. This limits both the temperature of the steam and also the effectiveness of the power plant. The corrosion in biomass-fueled plant was described.

• Journal of Adhesion and Interface
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• 제11권2호
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• pp.76-83
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• 2010

The extensive use of fossil resources over the past century resulted in dwindling supply and surging price of oil and it is strongly suspected that irreversible global climate change might be due to carbon dioxide emitted from combustion of fossil carbons. With this regard, much attention is recently paid to renewable and sustainable resources as alternatives to petroleum. In this review, we considered a range of efforts to replace petroleum-derived chemicals, particularly adhesive materials with renewable and sustainable plant-based biomass feedstock.

• Journal of Forest and Environmental Science
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• 제34권1호
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• pp.12-23
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• 2018

Quantitative information on biomass and available nutrients are essential for developing sustainable forest management strategies to regulate atmospheric carbon. An attempt was made at Chilapatta Reserve Forest in Duars region of West Bengal to quantify its above and below ground carbon along with available "N", "P" and "K" in the soil. Stratified random nested quadrats were marked for soil, biomass and litter sampling. Indirect or non-destructive procedures were employed for biomass estimation. The amount of these available nutrients and organic carbon quantified in soil indicates that the forest soil is high in organic carbon and available "K" and medium in phosphorus and nitrogen. The biomass, soil carbon and total carbon (soil C＋C in plant biomass) in the forest was 1,995.98, 75.83 and $973.65Mg\;ha^{-1}$. More than 90% of the carbon accumulated in the forest was contributed by the trees. The annual litter production of the forest was $5.37Mg\;ha^{-1}$. Carbon accumulation is intricately linked with site quality factors. The estimated biomass of $1,995.98Mg{\cdot}ha^{-1}$ clearly indicates this. The site quality factor i.e. tropical moist deciduous with optimum availability of soil nutrients, heavy precipitation, high mean monthly relative humidity and optimum temperature range supported luxuriant growth which was realized as higher biomass accumulation and hence higher carbon accumulated.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.662-665
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• 2007

Since biomass is given the status of "renewable resource" in contrast to "exhaustible resource" e.q., fossil fuels, it plays a significant role in the sustainable development in future. We installed a downdraft gasifier for power generation from biomass materials. The biomass raw materials were wood chips with a moisture content of 18-23 wt.%, supplied at 40-50kg/h. This paper describes on the optimum gasification air ratio that is defined as the ratio of the oxygen mole supplied into the gasifier to the oxygen mole required for complete combustion for producing syngas supplied into a gas engine. The results showed that, lower heating value of the syngas was 1200 $kcal/m^3$ $_N-dry$ and cold gas efficiency of the gasification system was 72% under optimum operating conditions.

• Korean Journal of Microbiology
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• 제50권4호
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• pp.313-318
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• 2014

The world is in need of sustainable and eco-friendly energy sources such as microalgal biodiesel due to global warming and fossil fuel shortages. In this study, we compared the effectiveness of liquid fertilizer produced from swine manure and agriculture grade solid fertilizers as nutrient sources for microalgal biomass production. Mixed culture (Chlorella spp., Scenedesmus spp., Stigeoclonium spp.; CSS) was cultivated for 28 days in Small Scale Raceway Pond (SSRP) using various nutrient sources (swine manure liquid fertilizer, agricultural solid fertilizer, and mixture of these two fertilizers). Biomass and lipid productivity of fertilizer mixture were the highest at 0.8 g/L and 5.8 mg/L/day, respectively. These results indicate that the fertilizer mixture can provide microalgae necessary nutrient sources for stable biodiesel production and biomass growth. In addition, overall cost of microalgal cultivation and subsequently biodiesel production would be significantly reduced.