• Journal of Applied Biological Chemistry
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• 제59권1호
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• pp.75-81
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• 2016

Glutaraldehyde was used as a cross-linking agent for immobilization of purified ${\alpha}$-amylase from Exiguobacterium sp. DAU5. Befitting concentration of glutaradehyde and cross-linking time is the key to preparation of cross-linking chitosan beads. Based on optimized immobilization condition for ${\alpha}$-amylase, an overall yield of 56% with specific activity of 2,240 U/g on chitosan beads and 58% with specific activity of 2,320 U/g on chitosan-carbon beads was obtained. The optimal temperature and pH of each immobilized enzyme activity were $50^{\circ}C$ and 50 mM glycine-NaOH buffer pH 8.5, respectively. Those retained more than 75 and 90% of its maximal enzyme activity at pH 7.0-9.5 and after incubation at $50^{\circ}C$ for 1 h, respectively. In addition, the immobilization product showed higher organic-solvent tolerance than free enzymes. The mode of hydrolyzing soluble starch revealed that the ${\alpha}$-amylase possessed high hydrolyzing activity. These results indicate that chitosan is good support and has broad application prospects of enzyme immobilization.

• 환경위생공학
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• 제10권2호
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• pp.1-12
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• 1995

Under accelerated industrial developments environment pollution comes out to be very stirious. Especially the ions of heavy metal from wastewater, even if they are minimal, accumulated in ecology circle and do finally injury to human health. The general process for removal of heavy metals include coagulation and following sedimentation, ion -exchange and active carbon adsorption and sedimentation that applicate in popular, needs the expense of coagulant the additional treatment of sludge on the general process of coagulation and sedimentation. It is also a serious problem that the second pollution caused by coagulant. However chelating adsorption that uses natural chelating high- molecular compound has not pollution problem Among chelating high- molecules, the diminishing chitin that contained in crustaceans as crawfish and crab in our country with affluent water resources are easy to get. So it is advantageous to use this ubiquitous material for removing heavy metals because we could reuse natural resource. In this research, the author tested the effectiveness of the adsorption and removal of heavy metal ions by chitin and its derivatives. Chitin and cellulose became beads and used as flocculant, in this test. The results are as follows . First, bead showed higher removal ratio than powder in the comparative test on adsorbents such as chitin, chitosan and cellulose. Secondly, in the variety test by the kinds of adsorbent and time. chitosan bead and cellulose bead that showed the highest removal ratio. One hour need to remove the ions of heavy metal. Thirdly, the results of the adsorption degree test by pH revealed high removal ratio adsorption of chitin, cellulose and chitosan bead in alkalin condition but chitosan bead in acidic condition.

• 한국수산과학회지
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• 제34권5호
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• pp.563-569
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• 2001

1. 오징어 연골과 chitin, chitosan의 질소함량은 각각 $12.1\%,\;8.1\%,\;5.8\%$이며 회분함량은 각각 $0.8\%,\;9.4\%,\;0.2\%$로 나타났으며 오징어 연골로부터 최종적으로 만들어지는 chitosan의 수율은 $25\pm3\%$ 이었다. 2. 재탈아세틸화 하여 얻어진 chitosan의 탈아세틸화도는 $92\%$로 이는 NMR을 분석한 결과 chitin의 NMR 분석에서 보여지는 $CH_3$와 C=O기의 peak가 거의 나타나지 않았으며 또한 $C_3, C_5$가 $\beta-chitin$에서는 역평행 구조로서 2개의 signal로 나타나는데 본 실험에서는 $\beta-chitin$에서 보여지는 단일의 signal로 나타났다. 3. Chitosan을 0.2M AcOH-0.1 M AcONa 용액에 녹여 $30^{\circ}C$에서 점도를 측정한 결과 Mark-Houwink 식과 Rinaudo의 상수로부터 $[\eta]=1.424\times10^{-5}M^{0.96}$이었으며 분자량은 $1.15\times10^6$이었다. 4. I.R spectrum을 측정한 결과 chitin은 $1,653 cm^{-1}$에서amide I bend가 $1,558 cm^{-1}$에서 amide II bend가 나타났으며 chitosan은 $1,601 cm^{-1}$에서 1개의 넓은 bend가 생겼다. N-acetylchitosan의 경우 chitin과 마찬가지로 $1,655cm^{-1}$에서 amide I bend가 $1,560 cm^{-1}$에서 amide II bend가 나타났다. 5. 아세틸 함량은 N-acetylchitosan 분말이 $5.9\%$, acetylchitosan bead가 $63.2\%$ , N-ACF-1이 $56\%$ , N-ACF-2가 $58.7\%$ 이었다. 6. Chitin, chitosan 및 N-acetylchitosan을 formic acid에 용해하여 실온에서 시간에 따른 고유점도 변화를 관찰한 결과 chitosan이 chitin, N-acetylchitosan 보다 비교적 점도가 높았지만 3개 모두 시간이 지남에 따라 점도가 현저히 저하되어 25일째에는 chitosan이 14.39 dL/g, chitin이 1.31 dL/g, N-acetylchitosan이 1.06 dL/g이었다.