• KSBB Journal
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• v.11 no.6
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• pp.696-703
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• 1996

The bacterium Serratia marcescens QM Bl466 produces selectively large amount of chitinolytic enzymes(about 1mg/L medium). Enzymatic hydrolysis of chitin to N-acelyl-${\beta}$-D-glucosamine(NAG) is performed by a system consisting of two hydrolases : chitinase and chilobiase. Objectives of this study included optimization of a microbial host by using chitin particles for chitinase/chitobiase production and secretion and also development of batch fermentation system for high cell density cultivalion of S. marcescens QM B1466. Also, the influence of chitin source and carboxymethyl(CM) chitin on chitinase/chitobiase production and NAG production was investigated. When carboxymethyl chitin was substituted for colloidal and practical grade chitin, the chitinase activity was increased about 7∼10U/mL. In this case, the ratio of chitinase/chitobiase was 30.03U/3.44U(9:1). The highest amounts of NAG(3.0g/L) was obtained.

• Fisheries and Aquatic Sciences
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• v.6 no.1
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• pp.1-6
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• 2003

A chitinolytic enzyme-producing bacterium was isolated from sea water on the coast of Busan. The bacterium was identified as Aeromonas sp. based on its morphological, cultural and biochemical characteristics and designated Aeromonas sp. J-5003. The strain produced two chitinoloytic enzymes: chitinase and chitobiase. The optimum culture conditions of the strain for production of chitinoloytic enzymes were investigated. For the production of chitinase, the major components of medium were colloidal chitin $0.5\%$, glucose $0.2\%$, yeast extract $0.25\%$ and peptone $0.25\%$ while for the production of chitobiase, they were colloidal chitin $0.5\%$, galactose and tryptone $0.2\%$. The optimum cultural temperature and initial pH for the production of chitinase and chitobiase were $30^{\circ}C$ and pH 7.0, respectively.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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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$^{\circ}C$.

• Fisheries and Aquatic Sciences
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• v.6 no.1
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• pp.7-12
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• 2003

Chitinase and chitobiase produced by Aeromonas sp. J-5003 were purified and characterized. The chitinase was purified to 19.4 folds by gel chromatography and ion-exchange chromatography with the overall yield of $2.2\%$ and the specific activity of 93.1 unit/mg. The purified enzyme showed a single band on SDS-PAGE with MW 54kDa. The optimum pH and temperature of the purified chitinase were 7.0 and $37^{\circ}C$, respectively, and this enzyme stable in the range of pH 6.0 to 10.0 below $37^{\circ}C$. $Mg^{2+},\;Ca^{2+}\;and\;Na^+$ slightly stimulated the chitinase activity. However, $Hg^{2+}\;and\;Fe^{3+}$ inhibited chitinase activity. The chitobiase was purified by Sephacryl HR-l00 gel chromatography and DEAE-Sephadex A-50 ion-exchange chromatography with 33.5 purification folds and $4.3\%$ yield. The purified enzyme showed a single band with MW 63 kDa. The optimum pH and temperature of the purified chitobiase were 7.0 and $37^{\circ}C$, respectively. And this enzyme was stable in the range of pH 6.0 to 9.0 and at the temperature below $37^{\circ}C$. The enzyme activity was increased by $Mn^{2+}$, but it was inhibited by $Ag^+$.

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.151-158
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• 1997

For the production of potent chitinolytic enzyme from bacteria, screening was carried out. Of 100 samples from soil, fresh water and sea water collected from the Kyung-gi area, 7 strains of chitinolytic bacteria were isolated. Among them, Aeromonas hydrophila 5-3K showed the highest chitinolytic activity. Culture conditions of Aeromonas hydrophila for the production of chitinolytic enzyme were inverstigated and lytic enzyme was fractionated by the use of ammonium sulfate and Sephadex G-100. Maximum production of chitinolytic enzyme was obtained at pH 7.0 and 30$\circ$C with chitin concentration between 0.2% and 1.0%. Conditions for the enzyme production were optimized including fermentor cultivation. The chitinolytic system of Aeromonas hydrophila 5-3K was composed of two enzymes, chitinase and chitobiase.

• KSBB Journal
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• v.17 no.1
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• pp.100-105
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• 2002

N-acetyl-D-glucosamine oligosaccharides [(GlcNAc)n] whose degree of polymer-ization is from one to ten (n=1-10) were fractionated by column chromatography on CM-Sephadex. Electro dialysis from a partially deacetylated chitosan hydrolysate prepared crudely with the N-acetyl-D-glucosaminidase(chitinase) and exo-N, N'-diacetylchito-biohydrolase(chitobiase) of Serratia marcescens QM B1466. Reducing sugar compositions and sequences of the N-acetyl-glucosamine oligosaccharides were identified by N-acetylation, randomly cleavage with chitinase and ego-splitting with chitobiase. N-acetyl-glucosamine heterochitooligosaccharides with glucosamine oligosaccharides, (GlcN)n at the reducing end residues together with $(GlcN)_1\sim(GlcN)_4$ were detected. Separation was accomplished by prefractionation with election by 0 to 1.0 M NaCl gradient solution. $(GlcNAc)_1 =4.25%,\; (GlcNAc)_2=4.49%,; (GlcNAc)_3=11.1%,\; (GlcNAc)_4=2.5%,$$ $(GlcNAc)_{5}$=0.64%, $(GlcNAc)_{6}$=2.12% and $(GlcNAc)_{7}$=1.21%, respectively, were crystallized after electrodialysis and lyophilization Each N-acetyl-D-glucosamine oligosaccharides content were detected by HPLC.

• Macromolecular Research
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• v.16 no.1
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• pp.1-5
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• 2008

The enzymatic hydrolysis of chitin has been studied for almost a century, and early work established that at least two enzymes are required, a chitinase that mainly yields the disaccharide N,N'-diacetylchitobiose, or $(GlcNAc)_2$, and a "chitobiase", or ${\beta}$-N-acetylglucosaminidase, which gives the final product G1cNAc. This pathway has not been completely identified but has remained the central concept for the chitin catabolism through the $20^{th}$ century1 including in marine bacteria. However, the chitin catabolic cascade is quite complex, as described in this review. This report describes three biologically functional genes involved in the chitin catabolic cascade of Vibrios in an attempt to better understand the metabolic pathway of chitin.