• ALGAE
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• 제35권1호
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• pp.91-106
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• 2020

Incorporating renewable fuel into practice, especially from algae, is a promising approach in reducing fossil fuel dependency. Algae are an exceptional feedstock since they produce abundant biomass and oils in short timeframes. Algae also produce high-valued lipid products suitable for human nutrition and supplement. Achieving goals of producing algae fuels and high-valued lipids at competitive prices involves further improvement of technology, especially better control over cultivation. Manipulating microalgae cultivation conditions to prevent contamination is essential in addition to promoting optimal growth and lipid yields. Contamination of algal cultures is a major impediment to algae cultivation that can however be mitigated by choosing extremophile microalgae. This work describes the isolation of alkali-tolerant / alkaliphilic microalgae native to South Florida with ideal characteristics for cultivation. For that purpose, water samples from Lake Okeechobee were inoculated into Zarrouk's medium (pH 9-12) and incubated for 35 days. Selection resulted in isolation of three strains that were screened for biomass and lipid accumulation. Two alkali-tolerant algae Chloroidium sp. 154-1 and Chlorella sp. 154-2 were poor lipid accumulators. One of the isolates, the diatom Fistulifera sp. 154-3, was identified as a lipid accumulating, alkaliphilic organism capable of producing 0.233 g L^-1 d^-1 dry biomass and a lipid content of 20-30% dry weight. Lipid analysis indicated the most abundant fatty acid within Fistulifera sp. was palmitoleic acid (52%), or omega-7, followed by palmitic acid (17%), and then eicosapentanoic acid (15%). 18S rRNA phylogenetic analysis formed a well-supported clade with Fistulifera species.

• 한국산학기술학회논문지
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• 제15권5호
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• pp.3327-3335
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• 2014

본 연구에서는 천연가스의 냉각을 위한 프로판을 냉매로 사용한 단일 및 다단 냉동 사이클에 대한 소요 에너지를 비교하였다. 이를 위해서 천연가스의 온도를$ -37.00^{\circ}C$까지 냉각시키기 위해서 프로판을 냉매로 사용하여 1단 압축 및 2단, 3단, 4단 압축을 이용한 냉동 사이클에 대한 비교 연구를 수행하였다. 전산모사를 위해 한국가스공사로부터 제공받은 천연가스 조성을 적용하였으며, 열역학 모델식으로는 Peng-Robinson 상태방정식을 적용하였다. 냉동기 압축 단수가 증가할수록 응축기의 heatduty는 점점 줄어드는 것을 알 수 있었다. 4단 압축공정의 경우 1단 압축공정에 비해 응축기의 heatduty는 약 20.36% 정도 감소하였으며 냉매의 총 순환 유량은 약 14.53% 감소하였다. 또한 4단 압축공정의 경우 1단 압축공정에 비해 압축기의 총 소요 동력은 약 41.61% 감소함을 알 수 있었다.

• 한국응용과학기술학회지
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• 제18권2호
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• pp.103-110
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• 2001

Resource recovery and recycling of materials and products, including polyurethanes is viewed as a necessity in today's society. Most urethane polymers are made from a polyol and a diisocyanate. these and be chemicals such as water, diamines or diols that react with isocyanate groups and add to the polymer backbone. The problems of recycling polyurethane wastes has major technological, economic and ecological significance because polyurethane itself is relatively expensive and its disposal whether by burning is also costly. In general, the recycling methods for polyurethane could be classified as mechanical, chemical and feedstock. In the chemical recycling method, there are hydrolysis, glycolysis, pyrolysis and aminolysis. This study, the work was carried out glycolysis using sonication ant catalyzed reaction. Different kinds of recycled polyols were produced by current method(glycolysis), catalyzed reaction and sonication as decomposers and the chemical properties were analyzed. The reaction results in the formation of polyester urethane diols, the OH value which is determined by the quantity of diol used for the glycolysis conditions. The glycolysis rates by sonication for the various glycols, increased as fallows: PPG

• 한국응용과학기술학회지
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• 제31권3호
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• pp.453-465
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• 2014

본 논문에서는 바이오매스로부터 급속열분해를 통해 난방용, 발전용 및 수송용 연료로 사용하기 위해 바이오오일을 생산하는 기술개발 현황을 나타내었다. 바이오매스를 작은 규모의 액체연료로 전환하기 위해 가장 효율적인 방법 중 하나는 급속열분해이다. 급속열분해를 통한 바이오오일은 $450^{\circ}C{\sim}600^{\circ}C$ 온도에서 바이오매스가 신속히 열분해 되어 증기 급냉를 위해 외부 산소가 없는 조건에서 생산된다. 이 바이오오일은 최초 건조 바이오매스 기준 최대 75 무게%까지 생산할 수 있지만, 일반적으로 60-75 무게% 수준이 적합하다. 본 연구에서는 바이오매스의 원료특성, 바이오오일 생산원리, 바이오오일의 특성 및 활용분야에 대한 최근의 개발현황을 살펴보았다.

• Journal of Forest and Environmental Science
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• 제27권3호
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• pp.143-149
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• 2011

The possibility of employing biomass of Salix viminalis cv. Q683 as a resource of bio-energy was evaluated. The chemical analysis of S. viminalis cv. Q683 leaf biomass showed components such as, extractives (2.57%), lignin (39.06%), hemicellulose (21.61%), and cellulose (37.83%), whereas, its stem was composed of extractives (1.67%), lignin (23.54%), hemicellulose (33.64%), and cellulose (42.03%). The biomass of S. viminalis cv. Q683 was saccharified using two enzymes celluclast and viscozyme. The saccharification of S. viminalis cv. Q683 biomass was influenced by enzymes and their strengths. The optimal enzyme combination was found to be celluclast (59 FPU/g substrate) and viscozyme (24 FBG/g substrate). On saccharification the glucose from leaf and stem biomass was 7.5g/L and 11.7g/L, respectively after 72 hr of enzyme treatment. The biomass and enzyme-treated biomass served as the feedstock for ethanol production by fermentation. The ethanol production from stem and leaf biomass was 5.8 g/L and 2.2 g/L respectively, while the fermentation of the enzymatic hydrolysates yielded 5 g/L to 8 g/L bioethanol in 72 hours.

• 멤브레인
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• 제29권2호
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• pp.67-79
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• 2019

고순도 프로필렌(프로펜)은 옥탄가를 높이는 화합물이며 산업적으로 중요한 화합물들의 원료가 된다. 프로판 혼합물로부터 프로펜을 정제하는 것은 비슷한 끓는점으로 인해 기술적으로 어려우며, 큰 비용이 요구된다. ZIF-8 분리막은 분자체 메커니즘에 의해 효율적으로 프로판으로부터 프로필렌을 분리할 수 있는 가능성 때문에 많은 연구가 진행되고 있다. ZIF-8 분리막에 대한 관심이 커지는 것은 소위 "gate opening" 효과 때문이다. 프로필렌/프로판 혼합물로부터 프로필렌 분리를 높이기 위해 "gate opening" 효과는 분리막 기공을 확장시켜 더 크고 무거운 프로판은 피드 흐름에 유지시키며, 프로필렌만 선택적으로 투과할 수 있도록 한다. 본 논문에서는 ZIF-8 분리막 제조에 널리 적용되는 방법들과 분리막을 통한 프로필렌 투과도 및 선택도에 영향을 주는 인자들에 대해 살펴보고자 한다.

• Journal of the Korean Wood Science and Technology
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• 제47권2호
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• pp.189-199
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• 2019

This study addresses the biorefinery feedstock from Pinus densiflora. This raw material is a major tree species in the Republic of Korea; it is renewable, has cost-effective, and is readily available. In this study, steam explosion of P. densiflora was performed in a reactor at $225^{\circ}C$ and with 1 to 13 min reaction times with or without previous water impregnation. The combined severity factor (Ro), which is an expression relating the reaction temperature and reaction time used in the steam explosion treatment, ranged from 3.68 to 4.79. The influence of both impregnation and steam explosion conditions were investigated by examining color variations, chemical composition, and mass balance on the pretreated solids. The results showed that steam-exploded P. densiflora that was not impregnated with water exhibited significantly darker color (chroma 28.8-41.4) than water-impregnated and steam-exploded P. densiflora (chroma 18.8-37.3). The increased ${\alpha}$-cellulose and lignin contents were detected as the severity factor increased. Furthermore, the ${\alpha}$-cellulose and lignin contents in the non-impregnated/steam-exploded P. densiflora were higher than those in the water-impregnated/steam-exploded P. densiflora. However, the decreased holocellulose content was detected as the severity factor increased. In mass balance, the holocellulose yield from water-impregnated/steam-exploded P. densiflora was higher than that from the non-impregnated P. densiflora.

• Journal of Microbiology and Biotechnology
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• 제29권3호
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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.

• Journal of the Korean Wood Science and Technology
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• 제47권3호
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• pp.360-370
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• 2019

Woody crops cultivated in short-rotation coppices are attractive sources of lignocellulosic materials for bioethanol production, since they are some of the most abundant renewable resources. In this study, we evaluated the effects of the growth period on bioethanol production using short-rotation woody crops (Populus nigra ${\times}$ Populus maxiwiczii, Populus euramericana, Populus alba ${\times}$ Populus glandulosa, and Salix alba). The carbohydrate contents of 3-year-old and 12-year-old short-rotation woody crop branches were 62.1-68.5% and 64.0-67.1%, respectively. The chemical compositions of 3-year-old and 12-year-old short-rotation woody crop branches did not vary significantly depending upon the growth period. However, the 3-year-old short-rotation woody crop branches (glucose conversion: 26-40%) were hydrolyzed more easily than their 12-year-old counterparts (glucose conversion: 19-24%). Furthermore, following the fermentation of enzymatic hydrolysates from the crop branch samples (by Saccharomyces cerevisiae KCTC 7296) to ethanol, the ethanol concentration of short rotation coppice woody crops was found to be higher in the 3-year-old branch samples (~ 0.18 g/g dry matter) than in the 12-year-old branch samples (~ 0.14 g/g dry matter). These results suggest that immature wood (3-year-old branches) from short-rotation woody crops could be a promising feedstock for bioethanol production.

• 한국폐기물자원순환학회지
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• 제35권7호
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• pp.587-599
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• 2018

The coffee grounds generated during the coffee extraction process contain several resources, but the technology for their recycling has not been commercialized yet, causing various environmental problems. Due to the recent increase in coffee consumption worldwide, the amount of coffee grounds produced has been continuously increasing, reaching more than 750 million tons. In Korea, about 120,000 tons of coffee waste are annually generated; however, most of them are landfilled or incinerated. Although there is still a shortage of coffee waste recycling technologies compared to the amount of coffee grounds produced, various recycling approaches are being actuated in many countries including Korea. In this study, the generation of coffee grounds at home and abroad, the status of coffee grounds recycling, and the associated technology development trends were investigated. The coffee grounds recycling has been studied in the fields of energy, adsorbent, construction, agriculture, and bio-foods. Research is most active in the energy and biotechnology areas; in particular, since the oil in the coffee grounds is valuable as a feedstock for biomass energy, the technology related to energy recovery is currently under development worldwide. Removed because confusing and unnecessary.