• Advances in environmental research
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• v.2 no.1
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• pp.19-33
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• 2013

Microalgae are receiving an increasing attention because of their potential use as $CO_2$ capture method and/or as feedstock for biofuels production. On the other hand the current microalgae-based technology is still not widespread since it is characterized by technical and economic constraints that hinder its full scale-up. In such contest the growth kinetics of Nannochloris eucaryotum (a relatively unknown marine strain) in batch and semi-batch photobioreactors is quantitatively investigated with the aim of obtaining the corresponding kinetic parameters suitable for process engineering and its optimization. In particular the maximum growth rate was evaluated to be 1.99 $10^{-3}\;h^{-1}$. Half saturation concentrations for nitrates ($K_N$) and phosphates uptake ($K_P$) were evaluated as 5.4 $10^{-4}\;g_N\;L^{-1}$ and 2.5 $10^{-5}\;g_P\;L^{-1}$, respectively. Yield factors for nitrogen ($Y_N$) and phosphorus ($Y_P$) resulted to be 5.9 $10^{-2}\;g_N\;g^{-1}$ biomass and 6.0 $10^{-3}\;g_P\;g^{-1}{_{biomass}}$, respectively. The possibility of using 100% (v/v) $CO_2$ gas as carbon source is also evaluated for the first time in the literature as far as N. eucaryotum is concerned. The strain showed a good adaptability to high concentrations of dissolved $CO_2$ as well as to low pH. The lipid content under 100% $CO_2$ is about 16.16 %wt $wt^{-1}$ and the fatty acid methyl esters composition of the extracted oil is in compliance with the European regulation for quality biodiesel.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.1
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• pp.103-108
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• 2015

Recent global warming has been recognized as the world economy development from fossil fuel use is the culprit. This study was reduce the fossil fuel has been developed in a number of alternative energy, As a fuel that can be produced in our country is a biofuel. Biofuels is a sustainable fuel having economically benefits and decreasing environmental pollution problems caused due to fossil fuel. A lot of research is progressing about the conversion of diesel biofuel as renewable clean energy. In this experiment were remodel the institution that has been used in fishing engine again produced an experimental apparatus were installed directly, were studied using various bio fuel like to help the economically and environmentally sound operation of the vessel. rapeseed oil, soybean oil, comprehensively analyzing the results the effects of the exhaust emission characteristics of the waste rapeseed oil is available in a marine engine with similar physical and chemical components of the fuel, and the fuel consumption ratio, NOx is slightly increased, but soot was confirmed a tendency to decrease much.

• Journal of Marine Bioscience and Biotechnology
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• v.10 no.2
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• pp.73-82
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• 2018

Chlorella are source of valuable compounds as lipids, proteins, carbohydrates, bioactive compounds. To continuous obtain the high-value materials of Chlorella protothecoides, we performed continuous cultivation after applying milking techniques to C. protothecoides grown with culture for 7 days in optical panel bioreactor (OPBR) system. Fatty acid and lutein in extracts from pre- and post-milking of C. protothecoides were analyzed using gas chromatography and high performance liquid chromatography, respectively. C. protothecoides were rich in unsaturated fatty acids with a high content of oleic acid(C18:1), which is suitable as a biofuel feedstock. The fatty acid content in pre- and post-milking of C. protothecoides was decreased from 126.424mg/g d.w. to 119.341mg/g d.w, and the lutein content decreased from 0.258mg/g d.w. to 0.178mg/g d.w. The results of this study demonstrate the feasibility of milking C. protothecoides for production of lipids for biofuels production. It was confirmed that microalgae can continuously obtain lutein present in a trace amount through a continuous culture from milking.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.580-586
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• 2023

Diversified fuel types such as methanol, hydrogen, liquefied natural gas, ammonia, biofuels, have been come to fore in consideration of the limitations, regulations, environmental perception and efficient use of resources on maritime sector. NE is described as a substantial alternative energy source on the marine vessels in the sense of de-carbonization and fuel efficiency activities carried out by IMO. Although NPVs have been constructed for the merchant, navy and supply fields over the years, their numbers are few and working ranges are quite limited. NE generation techniques, reactor types, safety and security issues in case of any leakage or radiation pollution are analyzed and comparisons are performed between fossil-based fueled and NP based on icebreakers. The comparison are conducted on the basis of dimensions, resistances and operational competences by the VIKOR. NP icebreakers operated in recent years occupy a notable position in the ranking, although fossil fueled ones are most prevalent. Consequently, refueling period and emissions are the principal benefits of NPVs. Nevertheless, the use of such systems on marine vessels especially for merchant ships may come to the fore when all concerns in terms of safety, security and society are resolved since the slightest mistake can have irreversible consequences.

• Journal of Power System Engineering
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• v.19 no.2
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• pp.90-95
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• 2015

Recently worldwide concern and research is being actively conducted on green energy which can reduce environmental pollution. A plant such as the natural rapeseed oil, soybean oil, palm, etc. is used as a bio source in home and industry. Biofuels is a sustainable fuel having economically benefits and decreasing environmental pollution problems caused due to fossil fuel, and it can be applied to the conventional diesel engine without changing the existing institutional structure. Waste vegetable oil contains a high cetane number and viscosity component, the low carbon and oxygen content. A lot of research is progressing about the conversion of waste vegetable oil as renewable clean energy. In this study, waste oil was prepared to waste cooking oil generated from the living environment, and applied to diesel engine to confirm the possibility and cost-effectiveness of biodiesel blend waste oil. As a result, brake specific fuel consumption and NOx was increased, carbon monoxide and soot was decreased.

• Journal of Power System Engineering
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• v.19 no.3
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• pp.29-35
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• 2015

Environmental pollution is produced by consumption of fossil fuel, therefore alternative fuels is interested for development of new energy resources and reduction of exhaust emissions for air pollution prevention. Biofuels are produced from new vegetable oil and animal fat, may be used as fuel without change of engine structure in diesel engine. In this paper, the test results on specific fuel consumption, combustion characteristics of neat diesel oil and biodiesel blends(10 vol.% biodiesel and 20 vol.% biodiesel) were presented using four stroke, direct injection diesel engine, especially this biodiesel was produced from biodiesel fuel at our laboratory by ourselves. This study showed that specific fuel consumption is increased slightly, on the other hand cylinder pressure, rate of pressure rise, rate of heat release and soot were decreased slightly in the case of biodiesel blends than neat diesel oil.

• KSBB Journal
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• v.24 no.6
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• pp.495-507
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• 2009

As we move into the 21st century, the importance of marine resources is certain to increase due to the accelerated exhaustion of land resources. For the sustainable development of the world, therefore, we need to develop marine chemical bioindustries which enable us to produce industrial chemicals, advanced materials, fuels, and minerals from marine resources such as seaweeds and seawater. In this review, we selected five marine chemical bioindustries which include 1) seaweed polysaccharide industry, 2) marine advanced materials industry, 3) marine biofuel industry, 4) marine sea salt industry, and 5) deep-sea water industry, and discussed the current status and future prospects of each industry sector. It has been assessed that the future of marine chemical bioindustry looks very promising although there are many needs for more intensive research investments on marine bioprocess development through close cooperation between marine biologists and biochemical engineers.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.837-844
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• 2015

Carob waste is a useful raw material for the second-generation ethanol because 50% of its dry weight is sucrose, glucose, and fructose. To optimize the process, we have studied the influence of the initial concentration of sugars on the fermentation performance of Saccharomyces cerevisiae. With initial sugar concentrations (S₀ ) of 20 g/l, the yeasts were derepressed and the ethanol produced during the exponential phase was consumed in a diauxic phase. The rate of ethanol consumption decreased with increasing S₀ and disappeared at 250 g/l when the Crabtree effect was complete and almost all the sugar consumed was transformed into ethanol with a yield factor of 0.42 g/g. Sucrose hydrolysis was delayed at high S₀ because of glucose repression of invertase synthesis, which was triggered at concentrations above 40 g/l. At S₀ higher than 250 g/l, even when glucose had been exhausted, sucrose was hydrolyzed very slowly, probably due to an inhibition at this low water activity. Although with lower metabolic rates and longer times of fermentation, 250 g/l is considered the optimal initial concentration because it avoids the diauxic consumption of ethanol and maintains enough invertase activity to consume all the sucrose, and also avoids the inhibitions due to lower water activities at higher S₀ .

• ALGAE
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• v.31 no.3
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• pp.257-266
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• 2016

Nitrogen is one of the most critical nutrients affecting cell growth and biochemical composition of microalgae, ultimately determining the lipid or carbohydrate productivity for biofuels. In order to investigate the effect of nitrogen sources on the cell growth and biochemical composition of the marine microalga Tetraselmis sp., nine different N sources, including NaNO₃, KNO₃, NH₄NO₃, NH₄HCO₃, NH₄Cl, CH₃COONH₄, urea, glycine, and yeast extract were compared at the given concentration of 8.82 mM. Higher biomass concentration was achieved under organic nitrogen sources, such as yeast extract (2.23 g L⁻¹) and glycine (1.62 g L⁻¹), compared to nitrate- (1.45 g L⁻¹) or ammonium-N (0.98 g L⁻¹). All ammonium sources showed an inhibition of cell growth, but accumulated higher lipids, showing a maximum content of 28.3% in ammonium bicarbonate. When Tetraselmis sp. was cultivated using yeast extract, the highest lipid productivity of 36.0 mg L⁻¹ d⁻¹ was achieved, followed by glycine 21.5 mg L⁻¹ d⁻¹ and nitrate 19.9 mg L⁻¹ d⁻¹. Ammonium bicarbonate resulted in the lowest lipid productivity of 14.4 mg L⁻¹ d⁻¹. The major fatty acids in Tetraselmis sp. were palmitic, oleic, linoleic and linolenic acids, regardless of the nutritional compositions, indicating the suitability of this species for biodiesel production.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.328-336
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• 2020

Parachlorella sp. is an efficient fatty acid producer that can be used in the production of biofuels, feeds, and fertilizers. Microalgae show varying responses to culture conditions, even those within the same species. In this study, growth and fatty acid composition of a newly isolated Parachlorella sp. from the Nakdong river of Korea in different culture media were investigated. The microalga was cultivated in 400 ml bubble column photobioreactors using BG-11, BBM, TAP, and modified TAP (MTAP) media. It was shown that using BBM led to greater fatty acid accumulation (34%), while using TAP medium led to greater biomass productivity (0.34 g/l/day). Composition of the TAP medium was modified to have the N:P ratio of BBM while also varying concentrations of N and P to improve fatty acid productivity. One of the modified TAP media, MTAP-1 (104.8 mgN/l, 135.2 mgP/l, N:P ratio = 0.77), showed the highest fatty acid concentration of 0.69 ± 0.04 g/l, while those from TAP and BBM were 0.48 ± 0.06 g/l and 0.40 ± 0.02 g/l, respectively. The results showed that microalgal fatty acid productivity could be enhanced by changing the N:P ratio and concentrations.