• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.250.2-250.2
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• 2010

빛과 공기 중의 이산화탄소를 고정화하여 생성되는 바이오매스(biomass)로부터 다양한 에너지 및 물질을 생산하는 연구는 석유고갈과 환경문제 해결의 한 방안으로서 활발히 진행되어 왔으며, 앞으로도 그 지속 가능성과 환경 친화성에 의해 바이오에너지 이용 및 보급은 꾸준한 증가세를 보일 것으로 전망된다. 바이오디젤, 바이오에탄올의 경우는 미국, 브라질, EU, 한국 등에서 상용화되어 사용되고 있으며 그 생산량이 계속적으로 증가하고 있다. 하지만, 바이오연료의 보급 증가는 식량 자원과의 충돌과 열대우림 파괴 등의 부작용을 일으키고 있다. 이러한 문제 해결의 일환으로 단위면적당 생산성이 대두, 유채보다 월등한 것으로 보고되는 미세조류에 대한 관심이 증가하고 있으며 우수 미세조류종 개발, 미세조류 고속배양 및 수확, 미세조류로부터 에너지 및 유용물질, 소재 생산에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 미세조류로부터 바이오디젤 원료유를 생산하기 위해 Soxhlet을 이용한 추출 방법을 이용하였다. 추출되는 오일은 사용 용매의 극성에 따라 물성과 추출 효율에 차이가 큰 것으로 나타났다. 강한 극성의 용매일 경우, 엽록소와 단백질이 같이 추출되는 문제가 있으며 약한 극성 용매는 세포벽의 방해로 용매가 세포내부로 흡수되지 못하는 문제가 있다. 추출 효율이 높은 극성용매의 경우 불순물을 제거해야 고순도의 바이오디젤의 생산이 가능하고 비극성 용매는 추출 오일의 물성은 좋으나 수율이 매우 낮게 측정되었다. 이러한 동시추출을 방지함과 동시에 추출 효율을 높이기 위해 본 연구에서는 세포벽 파괴 후 용매추출하는 방법으로서 미세조류를 Microwave에 노출시켜 오일 추출율을 증가시키는 전처리 연구를 수행하였다. 전처리시, Microwave에 의한 열 발생은 미세조류를 탄화시키기 때문에 열매체로서 물을 혼합하여 탄화를 방지하고 세포벽 내외부의 가열효과로 세포벽을 파괴하고자 하였다. Microwave에 의한 에너지 손실을 줄이며 세포벽 파괴에 효과적인 수분혼합비를 조사하였으며 Microwave에 노출 후 잔류수분을 건조하고 효율적으로 용매를 접촉시키기 위해 분쇄를 수행하였다. 모든 전처리 반응을 거친 미세조류에서 약 2배 증가된 추출수율을 얻을 수 있었으며, SEM을 통해 전처리 미세조류와 미전처리 미세조류를 분석해본 결과 전처리 미세조류의 다공성이 증가함을 확인하였다. 또한, 90%의 메탄올에 미세조류를 녹여 엽록소 함유량을 측정한 결과, 전처리 미세조류의 엽록소가 미전처리 미세조류보다 약 7배가량 감소함을 확인할 수 있었다.

• Korean Journal of Microbiology
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• v.37 no.1
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• pp.15-20
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• 2001

In this study, we have isolated bacterial cell wall lytic enzyme in the culture supernatant of Aspergillus sp. HCLF-4. This hydrolase showed cell wall lytic activity against Anabaena cylindrica. The extracellular enzyme was produced by Aspergillus sp. HCLF-4 when it was grown in a PDB media containing 0.05% heat killed Micrococcus luteus cells. The molecular weight of lytic enzyme was about 14.3 kDa. The optimal pH and temperature for the activity of this enzyme were 3.0~4.0 and $30^{\circ}C$, respectively. This hydrolase activity was reduced by $Na^{+}$, $Li^{+}$, $Ca^{2+}$, $Cu^{2+}$, $Fe^{3+}$, EDTA, and PMSF, whereas it was increased by $Mg^{2+}$, $Mn^{2+}$>. The enzyme has N-acetylmuramyl-L-amidase or endopeptidase activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.4
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• pp.401-408
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• 1985

The yeast cell wall lytic action of the alkaline AL-protease, which was found out of the crude Zymolyase that a kind of yeast cell wall lytic $endo-{\beta}-1$, 3-glucanase produced from Arthrobacter luteus, was investigated with the viable cells of S. sake and it's cell wall preparation. AL-protease on the lysis of the viable yeast cells showed very low activities with the alone, but the lytic activities were highly increased with the combination of AL-protease and Zymolyase. On the stepwise treatment of the viable yeast cells with AL-protease and Zymolyase, the cells were lysed highly only by the course having a treatment with Zymolyase after pretreatment with AL-protease. Thus synergistic action of AL-protease was not observed with any some commercial enzymes, known as a type of alkaline and serine protease such as AL-protease, and was also found to be affected greatly by the culture conditions and species of the yeast tested. AL-protease caused the release of some peptide and a lot of sugar from the cell wall preparation, but could not lysed the cell wall more than 66%. Whereas Zymolyase could lysed the cell walls almost completely with alone. On the basis of these results, the synergistic action of AL-protease on the lysis of S. sake cells is hypothesized that at first AL-protease bind to the yeast cell surface layer consisting of mannan and protein, and then changes their conformation to facilitate the penetration of Zymolyase from the outside to the inside framework layer constituted of alkali insoluble ${\beta}-1,\;3-glucan$.

• Journal of Aquaculture
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• v.22 no.1
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• pp.68-73
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• 2009

Yeast has been widely used as a food organism for mass culture of rotifer and also considered as a partial substitute food for microalga in shellfish culture. But the dietary value of yeast is poorer than that of microalga due to its low nutrition and thick cell wall. This study was carried out to find a nutritious yeast species as a food organism and to investigate the nutritional value of manipulated yeast for shellfish. First of all, three species of yeast (Saccharomyces cerevisiae, Candida utilis, Kluyveromyces fragilis) and their manipulated yeast were tested on the survival (%) and growth of Artemia nauplii and Mytilus edulis larvae, which were representative filter feeding animal and easy to control. The survival (%) and growth of Artemia nauplii fed C. utilis were higher than those fed S. cerevisiae or K. fragilis. The growth of Artemia nauplii and M. edulis larvae, which were fed manipulated yeast was higher than that fed non-manipulated one. The manipulated yeast with higher removal rate of cell wall showed better dietary value for Artemia nauplii and M. edulis larvae. M. edulis larvae fed mixed-diet with Isochrysis galbana (50%) and manipulated C. utilis (50%) showed significantly higher growth than those fed single-diet with I. galbana. It means that manipulated C. utilis can substitute I. galbana at least 50% for M. edulis larvae.

• Journal of Plant Biology
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• v.34 no.2
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• pp.129-136
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• 1991

Two cell types, tip cells and hyphal cells, were found at the front of Cuscuta australis endophyte growing into the stem parenchyma of the host plant, Trifolium repens. Each tip cell developed into an elongate, filamentous hypha. The cells of both types possessed a dense cytoplasm including abundant organelles and enlarged nuclei with the deeply lobed envelope. The unevenly thick walls were observed in certain tip cells. The wall penetrated through the middle lamellae of the host cells and engulfed the debris of broken host cells. Some front cells had the plasmalemma-wall invaginations, which increased the surface area and would facilitate material uptake from the host No plasmodesmata between the host and parasite cells were found; instead, an apoplastic continuity was established by fused cell walls at the interface of the two partners. The apoplast was thought to be the main route for water and nutrients transport.nsport.

• Journal of the Korean Society of Food Culture
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• v.6 no.3
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• pp.229-235
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• 1991

This study is performed to investigate the relation between cell components and hardness which affect to the quality of dried persimmons. Moisture contents of dried persimmons were interrange of 30 to 36%. Enpung Junsi (EJ), Dungsi (Young dong) (DY) and Haman Susi (HS) had higher moisture contents than Dungsi (Sang Ju) (DS), Kojongsi (KS) and Hagakure (HK). Hardness was high in the varieties which has low moisture content such as DS, KS and HK. The significant differences of hardness and fracturability among varieties were appeared conspicuously but those of cohesiveness, adhesiveness and springiness were not appeared. Crude cell wall content, pectin and calcium content of cell wall were high in hard varieties. In the pectin fractions, water soluble pectin content was high in EJ, HS and DY but that of acid and alkali soluble pectin were high in DS, KS and HK. The cell wall of high hardness varieties observed thick and firm than that of low hardness varieties.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.180-185
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• 1997

This work was carried out to investigate change of polygalacturonase activities and polygalacturonase patterns by gel filtration chromatography during softening of persimmon and jujube fruits. During softening of two kinds of fruit, polygalacturonase activities of water-soluble and salt-soluble proteins were increased, but that of cell wall-bound proteins was decreased. In water-soluble and salt-soluble proteins of persimmon fruits, two peaks of polygalacturonase activity were separated in mature stages, but one peak in soft stages. During softening of those fruits, the peaks of polygalacturonase activity in water-soluble and salt-soluble proteins appeared on the same fraction with the peaks of polygalacturonase activity in cell wall-bound proteins.

• Food Science and Preservation
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• v.5 no.4
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• pp.350-354
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• 1998

This paper was investigated to changes of cell components during drying for studies on the softening of jujube fruits. The contents of alcohol-insoluble material, cell wall and water-soluble material were not changed at 6 days of drying, but alcohol-insoluble materials and cell wall were decreased at 9 days of drying, however water-soluble materials were increased. Pectin and hemicellulose were not changed at 6 days of drying. Pectin and alkali-soluble hemicellulose were remarkable decreased at 9 days of drying, but acid-soluble hemicellulose was increased. Water-soluble pectin was not changed at 6 days of drying, but increased at 9 days of drying. EDTA-soluble and insoluble pectin were decreased after 6 days of drying. The non-cellulosic neutral sugars were not changed at 6 days of drying. The contents of arabinose, galactose and total neutral suger were decreased at 9 days of drying.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.290-295
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• 2002

Among 12 lactic acid bacteria examined for their abilities to activate the complement system by hemolytic complement assay $(TCH_{50})$, Lactobacillus plantarum previously isolated from Kimchi showed high anti-complementary activity. The anti-complementary activity of the cell wall fraction of L. plantarum was more potent than that of the cytosol fraction, and both activities showed dose dependency. These high activities of the cytosol and the cell wall fractions were relatively resistant to the digestion with pronase, but sharply decreased after the treatment of $NaIO_4$. These results suggested that the complement activation by the cytosol and the cell wall fractions was mainly due to their polysaccharides. By the cross-immunoelectrophoresis using anti-human C3, the C3 activation products from both fractions were identified in $Ca^{++}$-free condition. Anti-complementary activity $(ITCH_{50})$ of the cell wall fraction was retained under the same condition, whereas that of the cytosol fraction was reduced considerably. From these results, it was inferred that the mode of complement activation by the cell wall fraction was mainly via alternative pathway, and that of the cytosol fraction was via both alternative and classical pathways.

• The Korean Journal of Mycology
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• v.35 no.1
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• pp.43-46
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• 2007

It was investigated that systemic acquired resistance (SAR) was induced in plant treated with a elicitor, which was derived from a non-virulent fungus. The elicitor, a hyphal cell wall component derived from fungus, induced a production of phytoalexin and a generation of reactive oxygen species (ROS) in potato treated with its low level concentrations. The effect of the fungus-derived elicitor was better than that of virulent pathogen-derived elicitor, which was well known in potato. These results, therefore, suggested potentcial use of fungus-derived elicitor as a new plant protector for commercial development.