• 한국식품과학회지
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• 제27권1호
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• pp.6-10
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• 1995

대롱새우껍질로부터 Neutrase처리로 단백질을 제거하고 0.1 M EDTA 2Na로 무기질을 제거하여 키틴을 분리 정제하였다. 키틴의 정제시 Neutrase 3 mg/ml을 첨가하여 pH 6.0, $50^{\circ}C$에서 처리하였을 때 단백질 제거 효과가 제일 좋았다. Neutrase처리에 의한 단백질 제거, 탈 아세틸화도 그리고 칼슘, 인함량은 시판 키틴과 거의 비슷하였다. 분자량은 $1.2{\times}10^{8}$ dalton이었고 키틴의 수율은 28.5%이었다.

• 미생물학회지
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• 제40권2호
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• pp.178-182
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• 2004

Saccharomyces cerevisiae의 class I 키틴생합성 효소인 Chsl의 활성측정법을 적용하여 Aspergillus nidulans의 영양균사에서 class I 키틴생합성 효소인 ChsC의 활성측정을 시도하였다. 그 결과, A. nidulans의 class I 키틴생합성효소도 효모류의 경우와 마찬가지로 트립신 처리에 의하여 활성화되는 효소전구체형태(zymogenic form)로 존재함을 알 수 있었다. 그리고 A. nidulans 야생형의 class I 키틴 생합성 효소활성은 트립신 처리에 의하여 6배 가량 증가되었다. 반면, chsC 유전자가 파괴된 돌연변이주는 트립신 처리에 의하여 효소활성이 증가되지 아니하였을 뿐만 아니라, 효소활성의 수준도 트립신을 처리하지 아니한 야생형의 class I 키틴생합성 효소활성과 거의 동일한 수준이었다. 따라서, 트립신을 처리하여 측정한A. nidulans 야생형의 class I 키틴생합성 효소활성 값에서 트립신을 처리하지 아니한 야생형의 class I 키틴생합성 효소활성을 제외한 값이 A. nidulans 야생형의 ChsC 효소활성임을 알았다. 이러한 조건을 토대로 영양균사 생장과정 동안 ChsC의 효소활성을 측정한 결과, chsC 유전자의 발현양상과 유사하게 액체배양상태의 영양균사가 무성분화능을 획득하는 시기로 알려진 시간대에 효소의 활성이 증가하였다. 이러한 결과는 이미 보고된 바와 같이 chs 유전자가 A. nidulans의 영양균사 생장에 관여함을 시사하고 있다.

• Journal of Microbiology and Biotechnology
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• 제2권3호
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• pp.197-203
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• 1992

Studies of the pretreatment of chitin and its subsequent hydrolysis by Aspergillus carneus chitinase are reported. Ball milling was found to be the most effective way among the pretreatment methods tested. Data are presented describing the effect of enzyme and substrate concentrations on the rate and extent of the hydrolysis process. It was found that the successive addition of enzyme improved the saccharification yield. Significant product inhibition of the chitinase was observed when N-acetylglucosamine concentration was 3.6％ or higher. Adsorption of enzymes to the substrate occurred during a 24 hr hydrolysis period. An initial rapid and extensive adsorption occurred, followed by gradual desorption which increased during the time of reaction. Intermediate removal of the hydrolyzate and continuation of the hydrolysis by adsorbed enzyme on the residual chitin was also investigated. A total of 75.4 g/l reducing sugars, corresponding to 69.2％ saccharificaton yield (as N-acetylglucosamine) was obtained. In addition an increase in the amount of recoverable enzymes was observed under these conditions. Evidence presented here suggests that the technique, whereby the free enzymes in the recovered hydrolyzate are re-adsorbed onto the new substrate, may provide a means of recirculating the dissolved enzymes.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권2호
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• pp.71-77
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• 1998

The strain of Serratia marcescens QM B1466 produces selectively large amount of chitinolytic enzymes (about 1mg/L medium). Enzymatic hydrolysis of chitin to N-acetyl-${\beta}$-D-glucosamine (NAG) was performed with a system consisting of two hydrolases (chitinase and chitobiase) produced by optimization of a microbial host consuming chitin particles. For the development of Large-scale biological process for the production of NAG from chitinaceous waste, the selection and optimization of a microbial host, particle size of crab/shrimp chitin sources and initial induction time using chitin as a sole carbon source on chitinase/chitobiase production and NAG production were examined. Crab-shell chitin(1.5%) treated by dilute acid and , ball-milled with a normal diameter less than 250m gave the highest chitinase activity over a 7 days culture. Crude chitinase/ chitobiase solution obtained in a 10 L fed-batch fermentation showed a maximum activities of 23.6 U/mL and 5.1 U/mL, respectively with a feeding time of 3 hrs, near pH 8.5 at 30$^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• 제9권1호
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• pp.1-8
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• 1999

Most carbohydrates exist in nature in an insoluble state, which reduces their susceptibility towards various carbohydrases. Accordingly, they require intensive pretreatment for structural modification to enhance an enzyme reaction. The direct conversion of insoluble carbohydrates has distinct advantages for special types of reaction, especially exo-type carbohydrase; however, its application is limited due to structural constraints. This paper introduces two novel heterogeneous enzyme reaction systems for direct conversion of insoluble carbohydrates; one is an attrition coupled enzyme reaction system containing attrition-milling media for enhancing the enzyme reaction, and the other is a heterogeneous enzyme reaction system using extruded starch as an insoluble substrate. The direct conversion of typically insoluble carbohydrates, including cellulose, starch, and chitin with their corresponding carbohydrases, including cellulase, amylase, chitinase, and cyclodextrin glucanotransferase, was carried out using two proposed enzyme reaction systems. The conceptual features of the systems, their reaction characteristics and mechanism, and the industrial applications of the various carbohydrates are analyzed in this review.

• 복식문화연구
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• 제12권6호
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• pp.999-1009
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• 2004

Chitin is a derived product from the shell of shrimp or crab. Chitosan, a deacetylated product of chitin, has widely been used in the biomedical sector, food industry, and textile industry. Chitosan exhibits fiber-forming property under certain conditions. Nonwoven fabrics made of chitosan fibers may have diverse applications in the industry. Previous studies have revealed that the dye uptake properties of natural dyestuffs improved by the chitosan pretreatment on the fabric specimens. In this case, fabric specimen is coated with acidic salt form of chitosan, which is different from the pure chitosan, since the coating process employes coating with the acidic solution of the chitosan and subesquent drying. In this study, chitosan nonwoven fabric samples were prepared from chitosan sample having deacetylation degree of $100\%$ and molecular weight of 650,000. Chitosan nonwoven fabrics maintain the form of $-NH_2$ end-group. These in turn exhibit higher dye uptake ability than the fabrics coated with chitosan acidic solutions do.

• 산업기술연구
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• 제36권
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• pp.33-37
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• 2016

Cellulose binding domains (CBDs) of cellulases are thought to assist in the hydrolysis of insoluble crystalline cellulose. To gain sufficient amount of CBDs, the self-cleavable intein tag was used for expression and purification of Trichoderma reesei cellobiohydrolase I CBD in E. coli. Synthetic CBD genes, CBD or linker-CBD were cloned into expression vector pTYB11. Recombinant CBDs were successfully purified by intein mediated purification with an affinity chitin-binding domain. The final yields of recombinant CBD and linker-CBD were 3.2 mg/L and 1.4 mg/L, respectively. The functional bindings of recombinant CBDs were confirmed by Avicel binding experiments. The simple and easy purification method using self-cleavable intein tag can be further used in pretreatment of crystalline cellulose or characterization of engineered CBDs.

• 한국키틴키토산학회지
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• 제23권4호
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• pp.267-276
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• 2018

본 연구에서는 숙취해소에 좋은 것으로 알려진 식품 소재와 황칠나무 추출물을 복합하여 in vitro 및 in vivo에서 알코올 유도된 간 손상에 대한 보호효과를 검토하였다. HepG2세포에서 300 mM 알코올과 SBJ 혼합물을 처리하였을 때 농도 의존적으로 LDH 수치가 감소하였으나 황칠나무 추출물을 제외한 복합물인 SBJ-복합물에서는 그 효과가 유의적으로 낮아지는 것을 관찰하였다. In vivo에서 SBJ 혼합물의 보호효과를 확인하고자 흰쥐에 알코올과 SBJ 혼합물을 투여한 결과, 알코올 투여 후 1시간까지 급격하게 혈중 알코올 수치가 EtOH군에서 증가하는 것이 관찰되었으며, SBJ 혼합물 투여군은 유의적인 차이로 감소되었음이 관찰되었으며 또한 농도의존적인 경향을 확인하였다. ADH 및 ALDH 활성의 증가는 SBJ 혼합물의 알코올 분해 및 대사산물의 제거 활성에 기여할 것으로 예상된다. 뿐만 아니라, 알코올에 의하여 증가한 LDH의 농도가 대조군과 유사한 수준으로 유지하는 것을 확인하였으며, GST, SOD, GPx 및 reduced glutathione와 같은 항산화 인자 및 효소의 활성은 대조군보다 EtOH군이 유의적으로 감소했으며, SBJ 혼합물에 의해 개선되는 경향을 관찰하였다. 이를 통해 SBJ 혼합물은 ADH, ALDH 활성 증가 및 항산화 방어계를 향상시킴으로써 산화적 스트레스 감소를 통한 간보호 효과가 있는 것으로 생각되며, 이러한 간보호에 미치는 주요한 추출물은 황칠나무 추출물임을 알 수 있었다. 이러한 결과를 토대로 향후 숙취해소 작용을 갖는 신규 식품소재로 활용될 수 있을 것으로 기대된다.