• Membrane Journal
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• v.29 no.2
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• pp.67-79
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• 2019

High purity propylene (propene) is an octane-enhancing chemical and also feedstock to industrially important chemicals. Purification of propylene from propane mixture is technologically and financially challenging because of their close boiling points. ZIF-8 membrane has been increasingly researched due to its great potential to separate propylene from propane effectively by molecular sieving. The increasing interest in ZIF-8 membranes lies in the so called "gate opening" effect. The gate opening effect enlarges the membrane pores and preferentially allows propylene to permeate through the membrane pores, while retaining the larger and heavier propane molecules in the feed stream in order to effect high propylene separation from propylene/propane mixture. In this paper, the widely accepted methods of ZIF-8 membrane preparation and parameters affecting propylene permeation and selectivity in ZIF-8 membrane are identified and reviewed.

• Journal of Microbiology and Biotechnology
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• v.29 no.3
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• pp.382-391
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• 2019

Many poultry eggs are discarded worldwide because of infection (i.e., avian flu) or presence of high levels of pesticides. The possibility of adopting egg yolk as a source material to produce polyhydroxyalkanoate (PHA) biopolymer was examined in this study. Cupriavidus necator Re2133/pCB81 was used for the production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3HHx), a polymer that would normally require long-chain fatty acids as carbon feedstocks for the incorporation of 3HHx monomers. The optimal medium contained 5% egg yolk oil and ammonium nitrate as a nitrogen source, with a carbon/nitrogen (C/N) ratio of 20. Time course monitoring using the optimized medium was conducted for 5 days. Biomass production was 13.1 g/l, with 43.7% co-polymer content. Comparison with other studies using plant oils and the current study using egg yolk oil revealed similar polymer yields. Thus, discarded egg yolks could be a potential source of PHA.

• New & Renewable Energy
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• v.19 no.4
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• pp.2-10
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• 2023

The current mandatory domestic biodiesel blending ratio is 3.5%, which is planned to be gradually increased to achieve carbon neutrality by 2050. The aim of this study was to improve domestic self-sufficiency in biodiesel raw oil by conducting a technical review on the possibility of utilizing waste oils, such as soup oil, chicken oil, and leather oil, as biodiesel feedstocks. These waste oils have an acid value that is too high to be converted directly into biodiesel. Therefore, a pretreatment to reduce the acid value is necessary. The neutralization process was examined as a potential technology for reducing the acid value. The oil recovery rate of the soup oil after neutralization was significantly low at 37.6 wt%. The oil recovery rates of leather oil and chicken oil were 66.49 wt% and 79.08 wt%, respectively. Based on biodiesel conversion experiment using waste oil with a reduced acid value, the conversions were analyzed as 89 wt%, 91.1 wt%, and 90.5 wt% for soup oil, leather oil, and chicken oil, respectively. Thus, it is technically possible to use soup oil, leather oil, and chicken oil as raw materials for producing biodiesel.

• Journal of Life Science
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• v.27 no.10
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• pp.1152-1160
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• 2017

A unicellular green alga was axenically isolated from a tidal pool on Ulleung-do, Korea. Morphological, molecular, and biochemical analyses revealed that the isolate belonged to Auxenochlorella protothecoides. The current study is the first record of this species in Korea. The microalgal strain was named as A. protothecoides MM0011 and its growth, lipid and pigment compositions, and biomass properties were investigated. The strain is able to thrive in a wide range of temperatures ($5{\sim}35^{\circ}C$) and to withstand up to 1.5 M NaCl. The results of GC/MS analysis showed that the isolate was rich in nutritionally important polyunsaturated fatty acids (PUFAs). Its major fatty acids were linoleic acid (27.6%) and ${\alpha}-linolenic$ acid (39.6%). Thus, this indigenous microalga has potential as an alternative source of ${\omega}3$ and ${\omega}6$ PUFAs, which currently come from fish and plant oils. Also, the HPLC analysis revealed that the value-added antioxidant, lutein, was biosynthesized as the accessory pigments by the microalga. A proximate analysis showed that the volatile matter content was 85.6% and an ultimate analysis indicated that the gross calorific value was $20.3MJ\;kg^{-1}$. Since 40.5% of total nitrogen and 27.9% of total phosphorus were removed from the medium, respectively, it also has potential as a feedstock for biofuel applications which could be coupled to wastewater treatment. In addition, the biomass may also serve as an excellent animal feed because of its high protein content (51.4%). Therefore, A. protothecoides MM0011 shows promise for application in production of microalgae-based biochemicals and as a biomass feedstock.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.484-490
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• 2013

This study was conducted to develop a simulation model for estimating the amount of such products as round wood, dimension lumber and the residual wood biomass produced by processing the individual trees of Larix kaempferi. In the model, the stem volume is assessed using the taper equations of the species to estimate the stem forms. Then, the model simulates the conversion processes of logs to round wood or lumber and assesses the maximum amount of the wood products by the lumber dimensions or round wood size. Also the model provides information on the amount of residuals for kerf and slabs produced on the conversion processes for sawn timber or round wood. According to the results of an application of the model to a L. kaempferi process, the trees greater than 12 cm of DBH can be converted to logs for lumber or round wood production. For the trees, of which DBH is available for log conversion, the maximum amount of final products by dimensions were analyzed. In this analysis, production of the bigger dimension lumber was assumed to be preferred to that of the smaller or round wood. This model can be used for assesment of forest economic value through estimation of merchantable volume for the trees, and assessment of mill residues which has the potential to provide significant amount of feedstock for bioenergy production as well.

• Journal of Plant Biotechnology
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• v.38 no.4
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• pp.241-250
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• 2011

The most part of vegetable oils is accumulated as storage lipid, triacylglycerol (TAG) in seed and used as energy source when seed is germinated. It is also used as essential fatty acids and energy source for human and animal. Recently, vegetable oils have been more and more an important resource because of the increasing demand of vegetable oils for cooking and industrial uses for bio-diesel and industrial feedstock. In order to increase vegetable oils using biotechnology, over-expressing or repressing the regulatory genes involved in the flow of carbon into lipid biosynthesis is critical during seed development. In this review, we described candidate genes may influence oil amount and investigate their potential for oil increase. Genes involved in the regulation from biosynthesis of fatty acids to the accumulation oils in seed can be classified as follows: First, genes play a role for synthesis precursor molecules for TAG. Second, genes participate in fatty acid biosynthesis and TAG assembly. Lastly, genes encodes transcription factors involved in seed maturation and accumulation of seed oil. Because factors/genes determining oil quantity in seed is complex as mentioned, recently regulation of transcription factors is being considered more favorable approach than manipulate multiple genes for increasing oil in transgenic plants. However, it should be figured out the problem that bad agricultural traits induced by the overexpression of transcription factor gene.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.369-374
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• 2014

The rice stem borer (Chilo suppressalis Walker) was one of the most destructive pest of rice for the 1960s and 1970s in Korea. Recently, it is newly recognized as a potential risk factor to the biomass yield of bioenergy crops. The current research was firstly conducted to investigate overwintering larvae population density and pattern of rice stem borer attacking Miscanthus sacchariflorus cv. Geodae 1 which is referred to as an ideal lignocellulosic bioenergy crop in Korea. Population density of larvae per $1m^2$ in stems and rhizomes at the Miscanthus experimental plots and rates of damage (wormhole, abscission) of M. sacchariflorus cv. Goedae 1 were investigated from October 2012 to March 2013. The population of larvae per $1m^2$ in stems of Miscanthus were 23, 4, 1, and 1 in October, November, December 2012, and January 2013, respectively. Over the same period, the population of larvae in basal stem rots and rhizomes were increased, whereas decreased in stems. Interestingly, the positions of larvae for overwintering in Miscanthus were confirmed to 5~10 cm below the soil surface such as basal stem rot and rhizome, whereas the most common overwintering position known in rice is a part of stem on the ground such as rice straw and rice stubble. It would suggest that the larvae gradually moved to bottom of stems and rhizomes in soil in line with decline in temperature. Moreover, the damage rates of stems per $1m^2$ were up to more than 50% in some places. In conclusion, this might be the first report that rice stem borer could affect the productivity of biomass of Miscanthus in case of mass cultivation. Moreover, it should be necessary to make a decision in insect control management for this bioenergy feedstock and other related crops.