• 자연과학논문집
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• 제6권1호
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• pp.5-39
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• 1993

한국 해산 남조류(Cyanophyta) 의 목록을 작성하고 분류학적 위치를 확인하기 위하여 우리나라 전해역에서 채집된 남조류를 대상으로 형태분류학적 연구를 시도하였다. 그 결과 동정된 한국 해산 남조류는 총 3목 6과 20속 36종이며, 이 중 14종이 우리나라에서 그 생육이 처음으로 확인된 미기록종 (Chroococcus minutus ($K\"{u}$tzing) $N\"{a}$geli, Merismopedia punctata Meyen, Microcystis ichtyoblabe $K\"u$zing, Dermocarpa leibleiniae (Reinsch) Born. et Thur., Hydrocoleum confluens (Setchell et Gardner) Drouet, Lyngbya sordida (Zanard.) Gomont, Phormidium forveolarum (Mont.) Gomont, Phormidium hansgieri Schmidle, Skujaella hildebrandtii (Gomont.) de Toni, Sphaeronema lithophila (Ercegovic) Umezaki, Spirulina tenerrima $K\"u$tzing, Hormothamnion enteromorphoides Grunow, Michrochaete aeruginea Batters, Michrochaete grisea Thuret ex Born. et flah.)이었다. 본 연구에서는 간섭현미경과 위상차현미경을 이용하여 체형이 미소한 남조류의 현미사진을 작성하였다. 형태학적으로 분류된 각 종을 대상으로 세포내 함유물을 관찰하여 그 중 PHB ($poly-\SS$-hydroxybutyrate) granule의 존재 유무를 조사하였으며, Lyngbya confervoides, Lyngbya semiplena, Phormidium corium, Sirocoleum kurzii, Hormothanmnion enteromorphoides, Calothrix crustacea들은 PHB를 함유하고 있음이 확인되었다. 이 결과는 생리생화학적 특성을 기초로한 남조류의 분류체계를 정립하기 위한 자료로 활용될 수 있을 것이다.

• Macromolecular Research
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• 제16권5호
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• pp.446-456
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• 2008

A recent theoretical approach based on the coupling of both the Flory-Huggins (FH) and the Association Equilibria thermodynamic (AET) theories was modified and adapted to study the miscibility properties of a multi-component system formed by two polymers (a proton-donor and a proton-acceptor) and a proton-acceptor solvent, named copolymer(A)/solvent(B)/polymer(C). Compatibility between polymers was mainly attained by hydrogen-bonding between the hydroxyl group on the phenol unit of the poly(styrene-co-vinyl phenol) (PSVPh) and the carbonyl group of the biodegradable and environmentally friendly poly(3-hydroxybutyrate) (PHB). However, the self-association of PSVPh and specific interactions between the PSVPh and the H-acceptor group (an ether oxygen atom) of the epichlorohydrin (ECH) solvent were also established in a lower extension, which competed with the polymer-polymer association. All the binary specific interactions and their dependence with the system composition as well as with the copolymer content were evaluated and quantified by means of two excess functions of the Gibbs tree energy, ${\Delta}g_{AB}$ and ${\Delta}g_{AC}$. Experimental results from fluorescence spectroscopy were consistent with the theoretical simulations derived with the model, which could also be applied and extended to predict the miscibility in solution of any polymer blend with specific interactions.

• Journal of Microbiology and Biotechnology
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• 제3권2호
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• pp.115-122
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• 1993

Poly(3-hydroxybutyrate)(P(3HB)) accumulation under nutrient-rich condition with various amounts of $(NH_4)_2 SO_4$ was systematically investigated. The results of the electron-microscopy and the solvent extraction showed that the P(3HB) accumulation is unavoidable even under nutrient-rich condition. This indicates that in a two-step culture of Alcaligenes eutrophus H16, the researches should be careful in interpreting the data of polyhydroxyalkanoates(PHAs) accumulation in terms of the carbon-source fed in the second step because the two-step culture product contains the P(3HB) produced under nutrient-rich condition. The polyester production capability in a two-step batch culture of A. eutrophus H16(ATCC 17699) was also investigated using various saccharides and their derivatives such as glucose, fructose, gluconic acid, glucaric acid, sorbitol, lactose, galactose, and mannose. The polyesters synthesized were characterized by 500 MHz$^{1}H-NMR$ spectroscopy, intrinsic viscosity$[\eta]$ measurement in chloroform and differential scanning calorimetry(DSC). 500 MHz $^{1}H-NMR$ analysis showed that all polyesters synthesized generally contained 1~2 mol% of 3HV. Another finding is that the glucose utilization can be increased by changing the autoclaving procedure of the substrate to enhance the P(3HB) production yield up to 46 wt% of P(3HB) in dry cells.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권5호
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• pp.237-251
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• 2002

The recent progress on metabolic systems engineering was reviewed based on our recent research results in terms of (1) metabolic signal flow diagram approach, (2) metabolic flux analysis (MFA) in particular with intracellular isotopomer distribution using NMR and/or GC-MS, (3) synthesis and optimization of metabolic flux distribution (MFD), (4) modification of MFD by gene manipulation and by controlling culture environment, (5) metabolic control analysis (MCA), (6) design of metabolic regulation structure, and (7) identification of unknown pathways with isotope tracing by NMR. The main characteristics of metabolic engineering is to treat metabolism as a network or entirety instead of individual reactions. The applications were made for poly-3-hydroxybutyrate (PHB) production using Ralstonia eutropha and recombinant Escherichia coli, lactate production by recombinant Saccharomyces cerevisiae, pyruvate production by vitamin auxotrophic yeast Toluropsis glabrata, lysine production using Corynebacterium glutamicum, and energetic analysis of photosynthesic microorganisms such as Cyanobateria. The characteristics of each approach were reviewed with their applications. The approach based on isotope labeling experiments gives reliable and quantitative results for metabolic flux analysis. It should be recognized that the next stage should be toward the investigation of metabolic flux analysis with gene and protein expressions to uncover the metabolic regulation in relation to genetic modification and/ or the change in the culture condition.