• Journal of Microbiology and Biotechnology
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• 제31권5호
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• pp.696-704
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• 2021

Levan is an industrially important, functional biopolymer with considerable applications in the food and pharmaceutical fields owing to its safety and biocompatibility. Here, levan-type exopolysaccharide produced by Pantoea agglomerans ZMR7 was purified by cold ethanol precipitation and characterized using TLC, FTIR, ¹H, and ¹³C NMR spectroscopy. The maximum production of levan (28.4 g/l) was achieved when sucrose and ammonium chloride were used as carbon and nitrogen sources, respectively, at 35℃ and an initial pH of 8.0. Some biomedical applications of levan like antitumor, antiparasitic, and antioxidant activities were investigated in vitro. The results revealed the ability of levan at different concentrations to decrease the viability of rhabdomyosarcoma and breast cancer cells compared with untreated cancer cells. Levan appeared also to have high antiparasitic activity against the promastigote of Leishmania tropica. Furthermore, levan had strong DPPH radical scavenging (antioxidant) activity. These findings suggest that levan produced by P. agglomerans ZMR7 can serve as a natural biopolymer candidate for the pharmaceutical and medical fields.

• 한국해양바이오학회지
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• 제13권1호
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• pp.28-47
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• 2021

Pectin is a natural polysaccharide and biopolymer that serves as a structural component of plant tissues' primary cell walls. Pectin is primarily composed of D-galacturonic acid linked by α-1, 4-glycosidic linkage and is further classified by the ratio of esterified galacturonic acid groups known as degree of esterification (DE). Pectin that contains more than half of its carboxylate units as methyl esters is known as a high methyl (HM) ester. Conversely, pectin that has less than half of its carboxylate units as methyl esters is known as a low methyl (LM) ester. Pectin has various bioactive properties, including anticancer, anti-inflammatory, antioxidant, antidiabetic, anticholesterol, antitumoral, and chemopreventive properties. Moreover, pectin is a useful biopolymer in biomedical applications. Biomedical engineering, which is founded on research aimed to improve the quality of life using new materials and technologies, is typically classified according to the use of hydrogels, nanofiber mats, and nanoparticles. This paper reviews the progress of recent research into pectin-based biomedical applications and the potential future biomedical applications of marine-derived pectin.

• Geomechanics and Engineering
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• 제28권4호
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• pp.375-384
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• 2022

The glacial tills and shales in Midwestern states of the USA often show strength degradation after construction. They are often in need of applying soil modification techniques to remediate their strength degradation with weathering process. This study investigated the weathering durability of these natural soils and biopolymer treated soils by comparing direct shear test results for wet-dry and wet-freeze-thaw-dry cycled specimens. The tests showed that untreated glacial tills maintained only 62% and 50% initial shear strength after eight wet-dry cycles and eight wet-freeze-thaw-dry cycles, respectively. These untreated soils could not withstand by themselves after 16 weathering cycles. The same soils treated with 1.5% (by dry weight) food-grade Xanthan gum maintained 140% and 88% initial shear strength of untreated soils after 16 weathering cycles for wet-dry cycles and wet-freeze-thaw-dry cycles, respectively. The same soils treated with 1.5% (by dry weight) Gellan gum maintained 82% and 60% initial shear strength of untreated ones after 16 weathering cycles, respectively. Similar results were obtained for crushed shales, manifesting that the biopolymerization method may be adopted as a new eco-friendly method to enhance the weathering durability of these problematic soils of glacial tills and shales.

• 생명과학회지
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• 제6권1호
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• pp.34-39
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• 1996

해양 다당류인 chitosan과 alginate를 이용해서 캡슐을 제조할 수 있었으며 그 성상을 물고기 알과 같은 형태 즉 인조어란의 성상으로 만들 수 있었다. 캡슐의 크기는 공기 사출기의 유속에 의해 1~5mm로 조절할 수 있었다. 캡슐의 기계적 강도는 chitosan요액의 pH와 이온의 농도에 의해 조절할 수 있었으며 원하는 어란의 기계적 강도를 가진 인조캡슐을 제조할 수 있었다. 이러한 인조어란 대체품의 제조이외에도 타분야인 의약, 산업 및 식품 분야에 이용이 가능한 캡슐로 이용 될 것이다.

• 한국환경과학회지
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• 제20권7호
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• pp.899-905
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• 2011

In order to develop bacterial cellulose (BC) with antimicrobial activity against pathogenic microorganisms, silver and chitosan were incorporated into BC, respectively. Experiment results showed that antimicrobial activity against pathogenic microorganisms was improved with increasing silver concentration. Chitosan also showed a direct proportion between its concentration and antimicrobial activity. These results suggest that antimicrobial effects of BC using silver and chitosan are well proven to be effective. We also tested the stainability of BC with natural colorant for the application of food industry. Stainability of BC was enhanced with increasing natural colorant concentration. Decolorization of BC stained was observed by dipping it into distilled water with one hour-intervals. As a result, there was no significant difference. Combination of natural colorant-stainability and antibiosis of BC is expected to be useful in making colored antibiotic BC in various industrial application areas, considering its antimicrobial activity, high stainability and low decolorization tendency.

• Geomechanics and Engineering
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• 제32권4호
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• pp.361-373
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• 2023

This study aimed to investigate the engineering properties and mechanical behaviors of polymer-fibers treated sand. Para rubber (PR), natural fiber (NF), and geosynthetic fiber (GF) were used to reinforce poorly graded sand. A series of unconfined compressive and splitting tensile strength tests were performed to analyze the engineering behaviors and strength enhancement mechanism. The experiment results indicated that the PR-fibers mixture could firmly enhance the strength properties of sand. The stress-strain characteristics and failure patterns have been changed due to the increase of PR and fibers content. The presence of PR and fibers strengthened the sand and enhanced the stiffness and ductility behavior of the mixture. The stiffness of reinforced sand reaches an optimum state when both NF and GF are 0.5%, while the optimum PR contents are 20% and 22.5% for the mixture with NF and GF, respectively. An addition of PR and fiber into sand contributed to increasing interlocking zone and bonding of PR-sand interfacial.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.21-28
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• 2007

The crude biopolymer (AS-S1) and endobiopolymer (AS-S2) were isolated from the dry stem bark of Acanthopanax sessiliflorus and tested for anti complement activity. The two potent anticomplement biopolymers, AS-1 and AS-2-Fr.I, were isolated by the combination of ion-exchange chromatography and gel filtration methods from the endo-biopolymers (AS-S2). The anticomplement activity of AS-1 (MW 12 kDa) and AS-2-Fr.I (MW 180 kDa) were found to be 84.4% and 100.0%, respectively, at the concentration of $25{\mu}g/ml$. Activated pathway of the complement system occurred in both classical and alternative pathways, as evidenced by crossed immunoelectrophoresis(CIEP), where a major pathway was detected to be the classical one. It was found that the anticomplement activities of the periodate oxidized were decreased significantly, but those of pronase digested biopolymers of AS-1 and AS-2-Fr.I were decreased very little. The AS-1 contained 2,4,6-tri-O-methyl-D-glucitol, 2,3,6-tri-O-methyl-D-galacitol, and 2,3,6-tri-O-methyl-D-galacitol, which indicated that AS-1 contained a $(1{\rightarrow}3),\;(1{\rightarrow}4)-linked$ glucopyranosyl residue and a $(1{\rightarrow}4)-linked$ galactosyl residue. AS-2-Fr.I contained mainly 2,4-di-O-methyl-D-mannitol and 2,3,4-tri-O-methyl-D-galacitol, which contained $(1{\rightarrow}3),\;(1{\rightarrow}6)$ linked mannosyl and $(1{\rightarrow}6)$ linked galactosyl residues.

• Mycobiology
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• 제36권2호
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• pp.106-109
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• 2008

The anti-tumor effects of exo- (EX) and endo-biopolymers (EN) produced from submerged mycelial cultures of Ganoderma applanatum (GA), Collybia confluens (CC), and Pleurotus eryngii (PE) were studied using Sarcoma 180 bearing mice. Solid tumor growth was inhibited most effectively when 40 mg/kg body weight (BW) of GA-EX or PE-EN was administered to the intraperitoneal (i.p.) cavity of BALB/c mice. The spleen and liver indexes were increased in mice following i.p. administration of GA-EX and PE-EN fractions. GA-EX and PE-EN reduced the tumor formation by 30.7% and 29.4%, respectively. GA-EX and PE-EN increased the natural killer (NK) cell activity of splenocytes by 41.3% and 28.9%, respectively.

• 한국의류학회지
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• 제28권11호
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• pp.1507-1515
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• 2004

Washable wool was developed using environmental-friendly spray UV-cure technique. Photocrosslinkable polymer, dextran-methacrylate, was synthesized starting from natural biopolymer, dextran. The aqueous solution of dextran-methacrylate was applied to wool fabric with various concentrations to find out the optimum condition in minimizing felting shrinkage. The wool fabric subsequently cured by 365 nm UV, The effects of UV-cure time and photoinitiator concentration on felting behavior of wool were examined. As the concentration of dextran-methacrylate increased, the felting shrinkage decreased gradually. At concentration 0.5g/ml, the felting shrinkage of wool was negligible. Other properties such as air permeability, moisture content, wrinkle recovery, thickness and wettability were also evaluated. The surface coating of dextran polymer onto wool fiber was identified by SEM.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2002년도 추계 수산관련학회 공동학술대회발표요지집
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• pp.187-188
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• 2002

Chitosan is a natural biopolymer of N-acetylglucosamine (-1,4 linked 2-acetamido-D-glucose), which is obtained after alkaline deacetylation of the chitin derived from the cell walls of lower plants and in the skeletal tissues of lower animals including arthropods and mollusks. In the recent studies, chitin and chitosan have attracted interest for converting them to oligosaccharides because the oligosaccharides are not only water-soluble but also possess versatile functional properties such as antimicobial activity (Jeon and Kim, 2000; Jeon et al., 2001). (omitted)