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Starch-enriched brewery waste (SBW), an unexplored feedstock, was investigated as a nutritious low-cost source for the mixotrophic cultivation of Ettlia sp. YC001 for biodiesel production. Stirring, autoclaving, and sonication were assessed for the SBW, in conjunction with pH. Stirring at 55 °C was found to be the best, in terms of the effectiveness of starch hydrolysis and yeast disintegration as well as cost. The treated solutions were found to support the mixotrophic growth of microalgae: 20 g/L of glucose medium resulted in the highest biomass production of 9.26 g/L and one with 10 g/L of glucose showed the best lipid productivity of 244.2 mg/L/day. The unsaturated fatty acids increased in the resulting lipid and thus quality well suited for the transportation fuel. All these suggested that SBW, when treated properly, could indeed serve as a cheap feedstock for microalgae-based biodiesel production.

The rapid economic growth of Vietnam has increased the amount of coal ash waste during electricity generation from coal-fired thermal power plants. This waste is being dumped even though the capacity of dumping sites will not be sufficient in the future. Accordingly, Korean technologies of recycling ashes, modifying them into a valuable product, and fixing carbon dioxide via carbon mineralization, can be an alternative to dumping. In this study, we aimed to investigate the feasibility of deploying carbon mineralization technology to Vietnam while considering technological, legal, and network perspectives. The material properties of coal ash and the applicability of coal ash recycling technology were briefly investigated in Vietnam. Legislation has progressed, focusing on recycling coal ash as a building material, with supportive measures on investment and international cooperation. Meanwhile, a bilateral network between Vietnam and the Republic of Korea at the institutional and governmental levels strengthened the implementation of practical technology cooperation. In conclusion, we considered various perspectives in terms of the technology transfer of recycling coal ash. This technology transfer model can contribute to enhancing the possibility of successful technology cooperation for solving the environmental problems of coal ash.

A new in-situ transesterification method was developed for wet biomass: K2CO3 was used as an alkaline catalyst and, Aurantiochytrium sp. KRS 101 as oleaginous DHA-producing microalgae. It was found that the presence of water greatly impaired the overall efficiency even with the powerful catalyst that had worked surpassingly well with dry biomass, and thus a mechanical aid like ultrasonication was needed to make advantage of full potential of the alkaline catalyst. The total fatty acid ethyl ester (FAEE) recovery yield of 94.6% was achieved with sonication at 100 g/L of biomass (40% moisture), 3% of K2CO3, 70 °C and 30 min. All these suggest that the ultrasound assisted in-situ transesterification can offer a feasible means for FAEE recovery and it was so by way of overcoming the physical limitation of mass transfer caused the presence of water and providing effective contacts between reactants.

In this study, pyrite (FeS2) was used for lipid extraction as well as esterification processes for microalgae-based biodiesel production. An iron-mediated oxidation reaction, Fenton-like reaction, produced an expected degree of lipid extraction, but pyrite was less effective than FeCl3 commercial powder. That low efficiency was improved by using oxidized pyrite, which showed an equivalent lipid extraction efficiency to FeCl3, about 90%, when 20 mM of catalyst was used. Oxidized pyrite was also employed in the esterification step, and converted free fatty acids to fatty acid methyl esters under acidic conditions; thus, the fatal problem of saponification during esterification with alkaline catalysts was avoided, and esterification efficiency over 90% was obtained. This study clearly showed that pyrite could be utilized as a cheap catalyst in the lipid extraction and esterification steps for microalgae-based biodiesel production.

A potentially economical and ecofriendly way of hydroxymethylfurfural (HMF) production was developed on the basis of a waste of banana peel and Fenton reaction. An optimal process condition was obtained by examining the effects of three key parameters including amount of hydrogen peroxide (H 2 O 2 ), amount of ferrous (Fe 2+ ) ion, and reaction time on HMF yield. This study may offer an alternative route for HMF production, indeed a sustainable one in that it makes the best use of a problematic bio-waste and also takes advantage of the simple nature of the Fenton process.

Algal residue after lipid extraction is problematic, yet its high nutrient content makes it a potential source for microbial cultivation. This study proved that algal residue suspension from acid-catalyzed hot-water extraction (AHE) can be used for oleaginous yeast cultivation. When AHE was applied into Nannochloropsis salina, lipid extraction efficiency over 90% was obtained versus the control extraction method using organic solvent, and a water layer containing algal residue nutrients was also produced. Cryptococcus sp. was cultivated in the algal residue suspensions from AHE and a control experiment, and growth was not observed in the control due to the toxicity of alcohol, whereas yeast can grow well in AHE (final cell density: 2.25 ± 0.4 g/L, lipid content: 23 ± 2.2%). The AHE method can be a good lipid extraction option for the recycling of algal residue, having the advantage of excluding organic solvents and dissolving residue without any extra processes.

In this study, electrically-facilitated forward osmosis (FO) employing proton exchange membrane (PEM) was established for the purpose of microalgae dewatering. An increase in water flux was observed when an external voltage was applied to the FO equipped with the PEM; as expected, the trend became more dramatic with both concentration of draw solution and applied voltage raised. With this FO used for microalgae dewatering, 247% of increase in flux and 86% in final biomass concentration were observed. In addition to the effect on flux improvement, the electrically-facilitated FO exhibited the ability to remove chlorophyll from the dewatered biomass, down to 0.021±0015mg/g cell. All these suggest that the newly suggested electrically-facilitated FO, one particularly employed PEM, can indeed offer a workable way of dewatering of microalgae; it appeared to be so because it can also remove the ever-problematic chlorophyll from extracted lipids in a simultaneous fashion.

Jerusalem artichoke was investigated as a cheap substrate for the heterotrophic production using a lab yeast strain Cryptococcus sp. Using Response Surface Method, 54.0% of fructose yield was achieved at 12% of dried Jerusalem artichoke powder, 0.57% of nitric acid concentration, 117°C of reaction temperature, and 49min of reaction time. At this optimal condition, nitric acid showed the best catalytic activity toward inulin hydrolysis and also the resulting fructose hydrolyte supported the highest microbial growth compared with other acids. In addition, lipid productivity of 1.73g/L/d was achieved, which is higher than a defined medium using pure fructose as a substrate. Lipid quality was also found to be generally satisfactory as a feedstock for fuel, demonstrating Jerusalem artichoke could indeed be a good and cheap option for the purpose of biodiesel production.

The aims of this work were to evaluate K2CO3 as a potent alkaline catalyst for in situ transesterification of Aurantiochytrium sp. KRS 101, one step process in which oil extraction and conversion take place together. This K2CO3-based in situ transesterification was optimized in terms of recovery yield of fatty acid methyl esters (FAMEs) by way of varying biomass concentration, reaction temperature, reaction time, and catalyst concentration. The optimal condition was achieved at 50g/L of biomass concentration and 1% of K2CO3 in the methanol, 25°C of reaction temperature, and 5min of reaction time, resulting in the FAME recovery yield over 90%. It was found that K2CO3 performed better than any other tested catalysts including acids, supporting the notion that K2CO3 is a promising catalyst, especially for in situ transesterification.

In this study, persulfate, a solid-type oxidant, was adopted as a substitute for hydrogen peroxide in extracting lipid from microalgae biomass. Microalgae cells were concentrated at pH 3 and with 200mg/L of ferric chloride, conditions which can activate oxidants such as hydrogen peroxide and persulfate. At a persulfate concentration of 2mM and a reaction temperature of 90°C, exceedingly high extraction efficiency over 95% was obtained, which was higher than with 0.5% hydrogen peroxide at the same temperature. This result showed that persulfate is sufficiently powerful and incomparably cheap enough to replace the potent yet expensive oxidant. It appears that combining iron-based coagulation and persulfate-based lipid extraction is indeed a competitive approach that can possibly lighten the process burden for the microalgae-derived biodiesel production.

In this study, ferric chloride (FeCl3) was used to integrate downstream processes (harvesting, lipid extraction, and esterification). At concentration of 200 mg/L and at pH 3, FeCl3 exhibited an expected degree of coagulation and an increase in cell density of ten times (170 mg/10 mL). An iron-mediated oxidation reaction, Fenton-like reaction, was used to extract lipid from the harvested biomass, and efficiency of 80% was obtained with 0.5% H2O2 at 90 °C. The iron compound was also employed in the esterification step, and converted free fatty acids to fatty acid methyl esters under acidic conditions; thus, the fatal problem of saponification during esterification with alkaline catalysts was avoided, and esterification efficiency over 90% was obtained. This study clearly showed that FeCl3 in the harvesting process is beneficial in all downstream steps and have a potential to greatly reduce the production cost of microalgae-originated biodiesel.

Purpose: DA-125 [(8S,10S)-8-(3-Aminopropanoyloxyacetyl)-10- [(2,6-dideoxy-2-fluoro-α-L-talopyranosyl)oxy]- 7,8,9,10-tetrahydro-6,8,11-trihydroxy- 1-methoxy-5,12-naphthacene-dione hydrochloride] is a novel anthracycline derivative with anticancer activity. In the present study, we compared the cytotoxicity of DA-125 with that of doxorubicin in H4IIE rat hepatoma cells and investigated the mechanistic basis. Because activation of MAP kinases, in particular c-Jun N-terminal kinase (JNK), is implicated in apoptotic cell death, the signaling pathways responsible for DA-125-induced apoptosis were studied. Methods: Cytotoxicity and apoptosis were measured in H4IIE cells and cells were stably transfected with a dominant-negative mutant of JNK1 (JNK1–) by MTT and TUNEL assays. Inhibition of topoisomerase II activity was determined in vitro. Drug accumulation and DNA binding affinity were determined by fluorescence spectroscopy. Results: The cytotoxicity of DA-125 was greater than that of doxorubicin (IC50 11.5 vs 70 µM). DA-125 induced apoptosis with 30-fold greater potency than doxorubicin. Inhibition of topoisomerase II by DA-125 was fourfold greater. The presence of excess β-alanine, a DA-125 moiety, failed to alter cytotoxicity and accumulation of DA-125, indicating that the improved cytotoxicity of DA-125 did not result from the β-alanine moiety. Greater cellular accumulation of DA-125 correlated with its high-affinity DNA binding. Although neither PD98059 nor SB203580 altered the degree of cytotoxicity induced by DA-125, JNK1– cells exhibited about a twofold greater viability than control cells. DA-125-induced apoptosis was also decreased in JNK1–-transfected cells. Conclusions: DA-125 potently inhibited topoisomerase II activity and induced apoptosis by a high rate of prooxidant production. DA-125 exhibited high-affinity DNA binding with improved cellular drug accumulation. Apoptosis induced by DA-125 involved the pathway of JNK1, but not ERK1/2 or p38 kinase

We developed mimetic materials for oil spill drills of the Korean Coast Guard. Two selection criteria were adopted: physical properties and eco-friendliness. To make the drill effective, a mimetic substance candidate must have similar physical properties to crude oil, in terms of buoyancy, transportability, and significant color contrast. To minimize the possible impact on the marine environment in general and marine industry in particular, it must also be eco-friendly and non-toxic, as a major portion tends to be evaded from cleaning/capturing devices. Considering these, therefore, we selected natural oils extracted from marine biomass and presented results obtained from lab evaluations and field tests.