• Applied Biological Chemistry
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• v.48 no.1
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• pp.16-22
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• 2005

Many chitosanases, glycosyl hydrolases that catalyze the degradation of chitosan, have been found in microorganism. In this paper, classification of the enzyme has been described, which is based on the amino acid sequence (families) and splitting patterns (subclasses). Glycohydrolytic mechanisms such as inversion and retention of the substrate anomer are also discussed in context of the families. Interrelationship among the primary structure, clan, anomeric conversion and the splitting patterns has been suggested. In addition, advanced definition of chitosanase was introduced through the investigation of enzymatic products from partially N-acetylated chitosan as a substrate.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.193-198
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• 1999

The optimal culture condition of Bacillus sp. P16 was investigated for production of an extracellular endo-splitting chitosanase. The best carbon and nitrogen sources for the chitosanase production were chitosan and tryptone, respectively. The best condition for the maximum activity was at $37^{\circ}C$ in a medium containing 0.5% powdered chitosan, 1% tryptone, and 1% NaCl(at initial pH 7.0) in a rotary shaker(200 rpm). In a jar fermenter, the culture duration shortened to $6{\sim}12$ hr for maximum activity and the enzyme activity increased about 100% compared with that of flask culture.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.245-252
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• 1998

The chitosanolytic capabilities of cellulases, glucosidases, proteases and commercial enzymes were evaluated, and effective chitosanolytic cellulases from T. viride, T. reesei and Celluclast, a commercial enzyme from T. reesei were characterized. The reaction of cellulase from T. viride, T. reesei and Celluclast was optimal at pH 5. 0 and $45{\sim}55^{\circ}C$. Max. chitosanolytic activities of cellulases from both T. viride and T. reesei were observed at the enzyme/chitosan ratio=0.1 and chitosan concentration=3.0%. For the possible application of commercial Celluclast to chitosan oligosaccharides production, 3%(w/v) chitosan was reacted with 1%(v/v) Celluclast at pH 5.0 and $55^{\circ}C$. The apparent viscosity decreased by 98% within 30 minutes reaction and Max. contents of 50% EtOH solubles were 70% at 15 hrs reaction. Total reducing sugars were also increased with reaction time and maintained approx. 13.5% after 2hrs reaction. In 15 hrs treated chitosan hydrolyzates, various kinds of chitosan oligosaccharides were produced and contents of chitosan hexamer, known for its antitumor activities, were about 8.0%, about 4 times higher values compared with acid hydrolysis method. The results suggested that chitosan oligosaccharides could be produced with low-cost cellulases from T. reesei.

• Microbiology and Biotechnology Letters
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• v.26 no.4
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• pp.345-351
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• 1998

In an effort to develop a potent system for the production of various dp (degree of polymerization) chitooligosaccharides, 32 enzymes or microbial systems were screened for chitosanolytic acitivity using chitosan as a substrate. The efficiency of each enzyme system was evaluated by the changes of turbidity and viscosity of chitosan solution, the amount of precipitate and the reducing sugar-producing activity in the enzymatic reaction mixture. Based on these assay methods for the chitosanase activity, Bacillus sp. P2l out of 32 screened systems showed highly potent endochitosanase, which was comparable with a commercially available enzyme (E7). Chitooligosaccharides of dp 3-7 were separated by TLC as major enzymatic reaction products, suggesting that the chitosanase from Bacillus sp. P2l be endo-splitting type.

• Journal of Life Science
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• v.18 no.11
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• pp.1617-1624
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• 2008

Chitin and chitosan, which is deacetylated form of chitin, are one of the most abundant biomass on the earth. They showed various biological activities including antimicrobial activity, heavy metal chelating, immune system activation, and have very diverse applications in food, pharmaceutical, medicinal, and environmental industry. There have been reported many chitin/chitosan-hydrolyzing enzymes, their structures and genes from three domains, archaea, bacteria, and eukarya. Carbohydrate hydrolyzing enzymes are classified in CAZy (Carbohydrate Active Enzymes) database according to their amino acid sequence similarity. Interestingly, chitinases and chitosanases are classified in various glycosyl hydrolase(GH) families, GH2, GH5, GH7, GH8, GH18, GH19, GH20, GH46, GH48, GH73, GH75, GH80, GH84, and GH85. Here, we review characteristics and structures of chitin/chitosan hydrolyzing enzymes according to glycosyl hydrolase families in order to provide information about gene mining.

• Food Science and Industry
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• v.53 no.1
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• pp.2-32
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• 2020

In recent years, significant importance has been given to chitooligosaccharides (COS) due to its potent notable biological applications. COS can be derived from chitosan which is commonly produced by partially hydrolyzed products from crustacean shells. In order to produce COS, there are several approaches including chemical and enzymatic methods which are the two most common choices. In this regard, several new methods were intended to be promoted which use the enzymatic hydrolysis with a lower cost and desired properties. Hence, the dual reactor system has gained more attention than other newly developed technologies. Enzymatic hydrolysis derived COS possesses important biological activities such as anticancer, antioxidant, anti-hypersentive, anti-dementia (Altzheimer's disease), anti-diabeties, anti-allergy, anti-inflammatory, etc. Results strongly suggest that properties of COS can be potential materials for nutraceutical, pharmaceutical, and cosmeceutical product development.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.817-822
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• 1998

The authors found out that Aspergillus oryzae ATCC 22787 has the activity to produce a pretty strong chitosanase. Therefore, the strain was used for preparing the chitosan hydrolysate with high antimicrobial activity. The antimicrobial activity of the chitosan hydrolysate was increased gradually with decreasing of viscosity of the solution. The chitosan hydrolysate showing viscosity $5{\sim}10{\;}cp{\;}(30^{\circ}C)$ of 2% solution was revealed the most strong antimicrobial activity. The growth of the Bacillus sp. isolated from the fish meat paste was inhibited with the concentration of 50 ppm. The astringent taste of chitosan solution was reduced with decreasing of viscosity of the solution. The fish meat paste products containing 0.3% chitosan hydrolysate was extended its shelf life by 6 days stored at $15^{\circ}C$, 4 days at $20^{\circ}C$ and 2 days at $30^{\circ}C$.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.563-566
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• 2000

In order to obtain microbial endochitosanase for enzymatic production of chitooligosaccharides from chitosan, we screened four microbes from soil and selected. Bacillus sp. HSB-21 which showed highest activity. Chitosanase, produced from isolating microbe, was endo-type and molecular mass of the enzyme was estimated as 21,000 by active staining. Its optimum pH and temperature were 5.5 and $50^{\circ}C$, respectively. It was stable in the pH range of 3.0 to 8.0 and up to $40^{\circ}C$. It did not produce chitomonosaccharide and produced chitooligosaccharide ranging from chitobiose to chitooctaose as major end-products from chitosan. The chitosanase from Bacillus sp. HSB-21 can be applicable to enzymatic production of chitooligosaccharide which has high degree of polymerization .

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.696-701
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• 2002

Optimal conditions for preparing of chitooligosaccharides from chitosan with cellulase was researched by response surface methodo-logy, Penicillium funiculosum derived cellulase was most effective for chitooligosaccharides production as the point of hydrolyzing activity and commercial utility. The result which measures the change of degrading ratio at time course, 10 hr reaction showed a exponential increase and after that time degrading ratio was not changed. The optimal conditions determined by response surface methodology with central composite design of total 26 species were $0.5\%$ of chitosan, 143 U enzyme, 49$^{\circ}C$ of reaction temperature, 13.2 hr of reaction time and pH 3.8. Major chitooligosaccharides produced from chitiosan on optimal conditions were dimer and trimer.

• KSBB Journal
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• v.13 no.2
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• pp.147-154
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• 1998

Enzymatic hydrolysis using an immobilized enzyme was carried out to produce chitosan oligosaccharides (COSs) from chitosan effectively. Chitosanase was immobilized on eight different carriers by physical adsorption. The enzyme immobilized on chitin had higher activity than those immobilized on the other carriers in spite of its lower adsorption. The activity of chitin-immobilized enzyme was more than 90% of the original activity. Optimal temperature of the immobilized enzyme increased by about $15^{\circ}C$ and its thermostability was excellent in relatively wide range of temperature. But its effects of pH did not improve compared to the free enzyme. The immobilized enzyme produced 153 mg/g chitosan of the reducing sugar for 3hrs of hydrolytic incubation time. The total content of higher oligomers, tetramer to hexamer, among amount of total COSs obtained for 2hrs was more than 90%. In kinetic parameters for both enzymes, immobilized enzyme showed lower affinity for substrate and reaction rate than free enzyme, however, no reduction of the rate for high substrate concentrations. Consequently, chitin-immobilized could effectively hydrolyse chitosan and produce the higher COSs without activity decrease in comparison with the free enzyme.