• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.110-116
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• 2010

Lactic acid (LA) fermentation by Lactobacillus salivarius ATCC 11741 immobilized on loofa sponge (LS) was evaluated. To increase the surface area of LS for cell immobilization, $H_2O_2$ and chitosan were introduced as surface modifying reagents. Four chitosans of different molecular weights were separately coated on LS. All experiments were conducted in shaking flask mode at 100 rpm rotating speed and $37^{\circ}C$ with 5% $CaCO_3$ as a pH regulating agent. The effects of initial glucose concentration were investigated in the range of 20-100 g/l on LA fermentation by free cells. The results indicate that the maximum concentration of LA was produced with 50 g/l glucose concentration. The immobilized cell system produced 1.5 times higher concentration than free cells for 24 h of fermentation. Moreover, immobilized cells can shorten the fermentation time by 2-fold compared with free cells at the same level of LA concentration. At 1% (w/v) chitosan in 2% (v/v) acetic acid, the Yp/s and productivities of various molecular weights of chitosans were insignificantly different. Repeated batch fermentations showed 5 effective recycles with Yp/s and productivity in the range of 0.55-0.85 and 0.90-1.20 g/l.h, respectively. It is evident that immobilization of L. salivarius onto LS permits reuse of the system under these fermentation conditions. Scanning electron micrographs indicated that there were more intact cells on the chitosan-treated LS than on the untreated LS, thus confirming the effectiveness of the LS-chitosan combination when being utilized as a promising immobilization carrier for LA fermentation.

• Fashion & Textile Research Journal
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• v.3 no.3
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• pp.277-282
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• 2001

The effect of chitosan on antibacterial activities of cotton, wool and polyester fibers was investigated by shake flask method. Chitosan was treated in 0.1%, 1% and 2% $NaBO_3$ solution to reduce the molecular weight in 4 steps, wadding of cotton, wool and polyester were treated in 0.1%, 0.3% and 0.5% of chitosan solution which were dissolved in 2% acetic acid aqueous solution. The antibacterial activities of the fiber wadding treated and untreated by chitosan against Escherichia coli, Proteus vulgaris and Stephylococcus aureus were measured by shake flask method. On the untreated waddings, cotton showed better antibacterial activities than wool, but on the treated ones, wool showed better than cotton. The antibacterial activity of polyester was better than that of cotton or wool which preserved before and after the chitosan treatment against the three kinds of bacteria. When the chitosan treated cotton waddings was retreated in NaOH aqueous solution, their bacterial activities decreased. After laundering, the antibacterial activities of the treated cotton and wool waddings kept good, but that of the treated polyester reduced by almost half.

• Journal of the Korean Applied Science and Technology
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• v.29 no.3
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• pp.503-515
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• 2012

${\alpha},{\beta}$-Dichlorosuccinic acid was synthesized through the reaction of maleic anhydride with $Cl_2$(g) and ultra violet(200~300nm) wavelength in the presence of $CCl_4$. The second reaction of N-(${\alpha},{\beta}$-dichloro)succinic acid contained glucosamine derivatives(I) was accomplished by a modification of the general acylation using excess ${\alpha},{\beta}$-dichlorosuccinic anhydride in the presence of 2% acetic acid with methanol as a solvent at elevated temperature($70^{\circ}C$). We considered organic acid derivatives were useful especially of treatment for the cultivating porphyra and skin beauty culture.

• Membrane Journal
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• v.6 no.4
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• pp.250-257
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• 1996

Surface crosslinked chitosan composite membranes were prepared with glutaraldehyde and surfuric acid. Effects of neutralization for complex between chitosan and acetic acid and of water permeability for substrate membranes on pervaporation performance were investigated. For ionically crosskinked membranes, effect of active layer thickness on separation factor of water/ethanol mixture was studied. With increasing the water permeability of the substrate, the membrane showed an increased separation factor, while it maintained a constant permeate flux. Neutralized chitosan composite membranes revealed a decreased separation factor and a constant permeate flux. When the thickness of the active layer increased, an optimum crosslinking time to achieve higher separation factor shifted to a prolonged times.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.203-210
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• 2000

The preparative methods of a chitosan-deposited activated carbon and its characteristics were studied by using three kinds of chitosan with different degree of deacetylation and average molecular weight. The procedure was consisted of the dissolution of chitosan into acid solution, impregnation of activated carbon, agitation, evaporation, and drying. When the chitosan-dissolved acid and its concentration, amounts of chitosan deposited, and agitation conditions were changed, the specific surface area, deposition state on surface, and stability were investigated, and amounts of Cr(VI) adsorbed was measured. In the preparation process, it was proper to agitate the chitosan-dissolved acetic acid solution at room temperature for 1hr. In the deposition of chitosan with low molecular weight, the specific surface area of activated carbon was greatly decreased even at low chitosan loading, but in the case of high molecular weight it was not nearly changed to 10wt% loading. It was known that chitosan was uniformly and physically deposited on activated carbon. The chitosan-deposited activated carbon was stable into the solution over about pH 6. The removal of Cr(VI) was remarkably enhanced by adding the adsorption function of chitosan to the surface of activated carbon with about 5wt% chitosan. It may be therefore used as an adsorbent for removing the pollutants in air and wastewater.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.8
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• pp.1079-1089
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• 1998

Various fabrics, including natural fibers, regenerated cellulosic fibers, synthetic fibers, blend yarn, and mixture fabrics, were treated with the solutions of high purity chitosan in 1% acetic acid, having high viscosity of 930cps or low viscosity of 8cps. Physical/ mechanical properties of the treated fabrics samples were measured using Kawabata Evaluation System and drape tester. From these, hand values and total hand values of the fabric samples were calculated using Kawabata-Niwa translation equations. KOSHI, SHARI, HARI values have increased for the treated samples, while FUKURAMI values have decreased in general.

• Textile Coloration and Finishing
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• v.18 no.6 s.91
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• pp.16-24
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• 2006

The purpose of this study is to improve the defects of chitosan crosslinked viscose rayon by ECH and to describe the change of hand of chitosan crosslinked viscose rayon fabrics. The chitosan crosslinked viscose rayon were manufactured by crosslinking process using ECH as crosslinking agent, 2 wt% aqueous acetic acid as a solvent of chitosan and ECH, and 20 wt% aqueous sodium hydroxide as crosslinking catalyst. Viscose rayon were first immersed in the pad bath of the mixed solution of chitosan and ECH, padded up to 100 wt% wet pick-up on weight of fiber(owf), precured on pin frames at $130^{\circ}C$ for 2 minutes, immersed in NaOH solution and finally wash and dry. Antimicrobial properties of the viscose rayon treated with chitosan were measured by the shake flask C.T.M. 0923 test method with staphylococcus aureus(ATCC 6538) as the microorganism. When the concentration of chitosan was increased chitosan crosslinked viscose rayon's LT, WT, B, 2HB and MIU were increased and G, 2HG, SMD, T and $T_m$ were decreased. On the other hand, WT, EM were decreased and RT was increased at $1{\times}10^{-2}M$ ECH. The optimum condition for crosslinking was that ECH concentration was between $1{\times}10^{-2}M\;and\;5{\times}10^{-2}M$. Antimicrobial effects of rayon fabric treated with chitosan was excellent.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.268-274
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• 1999

The chitosan solution was prepared by dissolving chitosan into 2 wt % aqueous acetic acid solution and then chitosan beads were made by sol-gel method. The average molecular weight and the degree of deacetylation of the chitosan used here were determined to be $8.2{\times}10^5$ and 85%, respectively. chitosan beads were highly porous which was confirmed by SEM photography and BET. Adsorption equilibrium of $Cu^{2+}$ on porous chitosan beads could be represented by Sips equation. The diffusion of cupric ions in the chitosan beads could be explained by pore and surface diffusion mechanisms. Adsorption dynamics of $Cu^{2+}$ in fixed-bed could be simulated by linear driving force approximation (LDFA). It was proven that porous chitosan beads manufactured in this work are good adsorbents for the removal of $Cu^{2+}$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.739-745
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• 2015

To maintain quality of Delaware grapes during storage, grape samples were treated with 0.1% chitosan dissolved in 0.5% acetic acid, packaged with low density polyethylene film, and stored at 4 or $20^{\circ}C$ for 12 days. Chitosan treatment reduced initial populations of yeast and molds in grapes by 1.86 log CFU/g compared to that of the control. During storage, oxygen contents in packages of samples decreased, whereas carbon dioxide contents increased. In addition, regardless of storage temperature, changes in oxygen and carbon dioxide concentrations of grapes treated with chitosan were lower than those of the control. Hardness of samples decreased, and Hunter L, a, and b values were not significantly different among treatments. Regarding pH and total soluble content, grapes stored at $4^{\circ}C$ maintained pH and had greater total soluble content than those stored at $20^{\circ}C$. These results suggest that chitosan treatment and low temperature storage can be useful for maintaining microbiological safety and quality of Delaware grapes during storage.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.475-479
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• 2011

Chitosan is a natural polymer that has many physicochemical(polycationic, reactive OH and $NH_2$ groups) and biological(bioactive, biocompatible, and biodegradable) properties. In this study, chitosan nanoparticles were prepared using poly-${\gamma}$-glutamic acid(${\gamma}$-PGA) as gelling agent. Nanoparticles were formed by ionic interaction between carboxylic groups in ${\gamma}$-PGA and amino groups in chitosan. Chitosan(0.1~1 g) was dissolved in 100 ml of acetic acid (1% v/v) at room temperature and stirred overnight to ensure a complete solubility. An amount of 0.1 g of ${\gamma}$-PGA was dissolved in 90 ml of distilled water at room temperature. Chitosan solution was dropped through needle into beaker containing ${\gamma}$-PGA solution under gentle stirring at room temperature. The average particle sizes were in the range of 80~300 nm. The prepared chitosan/${\gamma}$-PGA nanoparticles were used to examine their removal of several heavy metal ions($Cd^{2+}$, $Pb^{2+}$, $Zn^{2+}$, $Cu^{2+}$, and $Ni^{2+}$) as adsorbents in aqueous solution. The heavy metal removal capacity of the nanoparticles was in the order of $Cu^{2+}$ > $Pb^{2+}$ > $Cd^{2+}$ > $Ni^{2+}$ > $Zn^{2+}$.