• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.41-47
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• 2004

This study was performed to investigate the antimicrobial effects of hetero-chitosans and their oligosaccharides on the halophilic bacterium, Vibrio parahaemolyticus. Nine classes of hetero-chitosan oligosaccharides were prepared based on their molecular weights, using an ultrafiltration membrane reactor system with chitosanase and celluase, from partially different deacetylated chitosans, 90%, 75%, and 50% deacetylated chitosan, respectively. Thirty-two strains of V. parahaemolyticus were isolated from various marine organisms such as shellfish, shrimps, octopus, and seabirds. Seventy-five percent deacetylated chitosan showed the highest antimicrobial acitivity. The minimal inhibitory concentration (MIC) was 0.5 mg/ml on 14 strains of V. parahaemolyticus, and MIC of the rest strains (18 strains) was 1.0 mg/ml. In addition, MIC of most hetero-chitosan oligosaccharides was 8.0 mg/ml. The results revealed that the antimicrobial effects of hetero-chitosans and their oligosaccharides against V. parahaemolyticus depend on the degree of deacetylation, their molecular weights, and strains tested.

• The Research Journal of the Costume Culture
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• v.11 no.3
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• pp.441-446
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• 2003

Water-insoluble chitosan with molecular weight of 2,000,000, 500,000, 80,000, and 40,000 and more than 90% of degree of deacetylation were used to test antibacterial activity of chitosan against a pathogenic bacteria, methicillin resistant Staphylococcus aureus(MRSA), which is being issued in the world. As experimental method, Agar plate Smear Method and Agar plate Contact Method were used. The moleculur weight of chitosan didn't exert significant influences on its antibacterial activity against MRSA but chitosan having molecular weight 40,000, 80,000 and 150,000 showed the excellent antibacterial activity. The antibacterial efHciency was excellent in applying it after chitosan was dissolved in acetic acid solution, while the antibacterial efficiency was not expressed nearly in case of applying after chitosan was dissolved in neutral water. Therefore, it is considered that chitosan can show the antibacterial efficiency only if a positive ion status of -NH₃/sup +/ is maintained. MIC of chitosan/acetic acid solution and cotton fabrics finished with chitosan/acetic acid solution showed in concentration of 0.05%.

• Proceedings of the Costume Culture Conference
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• 2003.02a
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• pp.24-25
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• 2003

Water-soluble chitosan and water-insoluble chitosan with molecular weight of 2,000,000, 500,000, 80,000, and 40,000 and more than 90% degree of deacetylation were controlled to evaluate the antibacterial activity of chitosan against a pathogenic bacteria, methicillin resistant Staphylococcus aureus(MRSA), which is being issued in the world. The Shake Flask Method and Modified Shake Flask Method were used to find out the antibacterial activities of 5types of chitosan/acetic acid solution, and the other antibacterial activities test with the cotton filter treated with chitosan /acetic acid solution. Those test methods showed the great differences ,but the results of the antibacterial activites showed the same difference.

• Korean Journal of Human Ecology
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• v.1 no.2
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• pp.119-128
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• 1998

Nonwoven fabrics for diaper coverstock were treated with chitosan solution by pad-dry method. Two chitosans of different molecular weigh(Mw) with similar degree of deacetylation(DDA) were used: Mw 1,800(chitosan oligomer, DDA 84%). Effect of chitosan treatment on the mechanical properties was investigated using KES-FB system. Primary hand values were calculated from mechanical properties using the same equation as the men's suiting equation with minor modification, and total hand values were calculated using new KN-5LNW equation for nonwoven fabrics developed by Kawabata et al. Increase in chitosan treatment concentration increased B, 2HB, WT, LT and RC, and decreased WC continuously. Chitosan treatment affected other mechanical properties regardless of molecular weight. Considering primary hand values obtained from mechanical properties, it was found that chitosan of Mw 180,000 and chitosan oligomer provided softer, smoother, and more bulky at below 0.05% and above 0.5% treatment concentration respectively. Samples treated with 1.0% chitosan oligomer solution, and 0.01％ chitosan solution of Mw 180,000 showed the best total hand values. (Korean J Human Ecology 1(2):119∼128, 1998)

• Textile Coloration and Finishing
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• v.10 no.3
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• pp.50-56
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• 1998

Nonwoven fabric was treated with chitosan solution to impart antimicrobial activities by pad-dry method. Antimicrobial activity was measured by Shake Flask Method. Two chitosans of different molecular weight(Mw) with similar degree of deacetylation(DDA) were used : ca. 1,800(chitosan oligomer : DDA 84%) and 180,000(DDA 86%). Chitosan oligomer displayed high antimicrobial activity against P. vulgaris at 0.01%, S. aureus and E. coli at 0.05% treatment concentration, shelving above 90% of reduction rate. Chitosan of Mw 180,000 was effective against S. aureus, E. coil and P. vulgaris at 0.05% treatment concentration, showing almost 100% reduction rate. While chitosan of Mw 180,000 shelved reduction rate above 75% against K. pneumoniae and P. aeruginosa at 0.5% treatment concentration, chitosan oligomer was not effective against them. Fabrics become stiffer and less air permeable as treatment concentration increases. Liquid strike-through time of the sample treated with 0.5% chitosan oligomer solution (3.0 sec) was comparable with a hydrophilic finished sample commercially available(2.6 sec).

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.87-91
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• 1997

A method for lab scale production and isolation of chitosan from mycelia of Cunninghamella blakesleeana IFO 4443 mutant was developed. Mutant of Cunninghamella blakesleeana IFO 4443-10 obtained by W radiation was cultivated in 5L jar fermentor at 3$0^{\circ}C$ for 3days. The fungus were grown well at pH 4.5 Chitosan was readily extracted from mycelia walls with alkali treatment. The maximum yield of chitosan obtained was 1012mg/L and degree of deacetylation was 84.6%.

• KSBB Journal
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• v.9 no.2
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• pp.174-179
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• 1994

Chitin was isolated from crab shell wastes and characterized for its chemical and physical properties. White powdered chitin was obtained through demineralizaticn, deproteinization and decoloration process. The contents of inorganics was less than 0.5%, whereas protein and lipid were almost removed. The results of IR spectroscopic analysis for the isolated chitin showed similar characteristics with that of Sigma product. Degree of deacetylation of purified chitin was significantly higher than Sigma product and viscosity average molecular weights was $2.3{\times}10^5~3.2{\times}10^5$. SEM analysis showed that the obtained chitin had the fibril shaped morphology.

• The Korean Journal of Food And Nutrition
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• v.13 no.3
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• pp.242-248
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• 2000

수산물 가공시 흘러나오는 폐수 중에 함유되어 있는 수용성 단백질을 chitosan에 흡착시키기 위하여 albumin과 hemoglobin, albumin-myoglobin 혼합단백질을 이용하여 chitosan과의 흡착 및 chitosan 제조조건에 따른 흡착효과와 chitosan의 수용성 단백질 흡착에 미치는 인자를 살펴본 결과는 다음과 같다. Chitosan위 탈아세틸화 조건을 60, 70, 80%로 달리하여, albumin, hemoglobin, albumin-myoglobin 혼합용액에 적용했을때 chitosan의 탈아세틸화도가 높을수록 chitosan과 단백질 사이의 흡착률은 높게 나타났다. 초음파 처리에 의하여 chitosan의 분자량이 작을수록 chitosan과 단백질 사이의 흡착률은 높게 나타났다. pH변화에 따른 chitosan과 수용성 단백질의 흡착률은 albumin 및 albumin-myoglobin 혼합용액에서는 pH 4.0에서, hemoglobin용액에서는 pH 7.0에서 흡착률이 높게 나타났다 chitosan과 수용성단백질과의 흡착에서 반응시간은 albumin및 albumin-myoglobin 혼합용액에서는 4시간, hemoglobin용액에서는 3시간까지 흡착률이 증가하였고, 그 이후의 시간이 경화하여도 흡착률의 증가는 거의 보이지 않았다. 수용성 단백질 용액에 NaCl 농도를 0.1M에서 1.0M로 증가시켜 첨가했을때 염의 농도가 높을수록 chitosan과 단백질 사이의 흡착이 잘 일어나지 않았다.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.5 no.1
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• pp.47-55
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• 1999

Applications of chitosan are related to molecular weight and degree of deacetylation(DOD) of chitosan completely. The molecular weight and DOD were greatly affected by the concentration of solution time and temperature. The degree of demineralization was not significantly different at $50^{\circ}C\;and\;70^{\circ}C$ after 30 minutes. Deproteinization decreased as process time increased. The nitrogen content was reached to 6.92% after 90 minute at $80^{\circ}C$, which is similar to theoretical nitrogen content of chitin. The DOD was 82.84% after 2 hours reaction and increased as the reaction time increased in the process. Viscosity and molecular weight are increased as recycling number of concentrated NaOH solution increased. Chemical, biological and physical properties of chitosan depend on the DOD and molecular size of the molecule. Tensile strength of the films from acetic acid solutions was between $28.9{\sim}33.6$ MPa and was generally higher than that of the films from lactic acid. Elongation of the films from lactic acid was between $97.0{\sim}109.7%$ and was generally higher than that of the films from the acetic acid. Water vapor permeability of the films prepared from lcetic acid solutions was between $1.9{\sim}2.3ng{\cdot}m/m^2{\cdot}s{\cdot}Pa$ and was generally higher than that of the films from the acetic acid.

• Applied Biological Chemistry
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• v.43 no.4
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• pp.309-313
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• 2000

For the use of Antartic krill(Euphausia superba Dana) as food resource, general composition, extracting condition of chitin and quality characteristics of chitosan were investigated. General composition of frozen krill(Euphausia superba Dana) was consisted of moisture 79.0%, protein 13.1%, lipid 4.0%, VBN 7.7mg%, ash 2.7%, others 1.2% and that of dried krill powder was moisture 5.6%, protein 56.1%, lipid 18.8%, ash 11.4%, others 8.1%. The condition of chitin extraction from krill powder was treated with 1N NaOH at $40^{\circ}C$ for removing protein, 1N HCl for excepting mineral substances and methanol for decoloring. The yield of chitin by new procedure developed was 3.7%. The composition of extracted chitin contents was moisture 7.1%, ash 0.4%, protein 3.5%, lipid 3.1%. The results of degree of deacetylation in chitosan at 50% NaOH, $121^{\circ}C$, for 2 hrs was showed 82%. At the same alkali concentration and reaction concentration, a longer reaction time gave a decreased degree of deacetylation. The apparant viscosity was 0.09241 Pa in 1% chitosan from krill and 0.13826 Pa in standard chitosan.