• Applied Biological Chemistry
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• v.39 no.6
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• pp.466-471
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• 1996

The survey on the chitinolytic activity of some plants was performed for the purpose of obtaining some reliable and inexpensive sources of chitinase. Rice, soybean for sprouting, kiwi fruit, almond and crude papain were investigated. Rice bran, seed coat of the soybean and the pericarp of kiwi fruit showed a considerable activity, while the bean after the removal of the seed coat, the mixture of rice integument and endosperm, polished rice, and defatted soybean powder didn't have any detectable activity. These crude enzymes have shown to contain both endo- and exochitinase activity. The effects of pH and temperature on the enzyme activity were variable. Furthermore we have observed the chitosanolytic activity from these enzyme Preparations. The rice bran had the highest activity in the enzymatic degradation of chitosan, and seed coat of soybean and the pericarp of kiwi fruit followed. On the basis of the fact that crude papain was not only commercially available but also the most potent in the endochitinase activity and the lowest in the exochitinase activity, we could conclude that crude papain was considered as the most suitable source of the chitinase among plants studied in this paper. In addition, rice bran was worth further investigation from the point of utilizing agricultural by-product.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.95-100
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• 1997

This study was aimed to survey inexpensive and reliable sources of chitinase from the animal origin. The stomach and its content of the broiler, the cod, the yellowtail and ${\beta}-glucuronidase$ from snail gut showed a considerable chitinolytic activity, while those of the bas didn't have any detectable activity. These crude enzymes was found to have both endo- and exochitinase activity. The effects of pH and temperature on the enzyme activity were variable. The hydrolytic products of colloidal chitin by the enzyme preparation from the broiler and the cod were chitooligomers having the degree of polymerization between 3 and 5. Furthermore we observed the chitosanolytic activity from these enzymes. In the degradation of chitosan the chyme of the broiler had the highest activity and ${\beta}-glucuronidase$ from snail gut followed. On the basis of the fact that the by-product of the broiler was not only commercially available but also the most potent in the endochitinase activity and the lowest in the exochitinase activity, we conclude that the gizzard and its chyme are considered as the most suitable source of the industrial chitinase among animals studied in this paper.

• Korean Journal of Veterinary Research
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• v.43 no.1
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• pp.139-144
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• 2003

A chitinase cDNA named CHT1 was cloned from the hard tick, Haemaphysalis longicornis, and the enzymatic properties of its recombinant proteins were characterized. The CHT1 cDNA encodes 930 amino-acid (aa) residues including a 22 aa putative signal peptide, with the calculated molecular mass of the putative mature protein 104 kDa. The E coli-expressed rCHT1 exhibited weak chitinolytic activity against $4MU-(GlcNAc)_3$. The rCHT1 protein with higher activity was obtained using recombinant Autographa californica multiple nuclear polyhedrosis virus (AcMNPV), which expresses rCHT1 under polyhedrin promoter. These findings suggest that the rCHT1 expressed in baculovirus-mediated Sf 9 cells has a high activity than E coli-expressed rCHT1.

• BMB Reports
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• v.38 no.1
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• pp.82-88
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• 2005

Bacillus cereus 28-9 is a chitinolytic bacterium isolated from lily plant in Taiwan. This bacterium exhibited biocontrol potential on Botrytis leaf blight of lily as demonstrated by a detached leaf assay and dual culture assay. At least two chitinases (ChiCW and ChiCH) were excreted by B. cereus 28-9. The ChiCW-encoding gene was cloned and moderately expressed in Escherichia coli DH5$\alpha$. Near homogenous ChiCW was obtained from the periplasmic fraction of E. coli cells harboring chiCW by a purification procedure. An in vitro assay showed that the purified ChiCW had inhibitory activity on conidial germination of Botrytis elliptica, a major fungal pathogen of lily leaf blight.

• The Plant Pathology Journal
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• v.22 no.2
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• pp.107-114
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• 2006

The white cottony stem rot pathogen Sclerotinia scierotiorum was subjected to 70 different isolates of actinomycetes indigenous to Jordan as biological control agents. Forty of them demonstrated chitinase activity on crab shell chitin agay (CCA) media and they were segregated into three groups: 14 highly active, 12 moderately active, and 14 with low activity, with average clearing zones of (4.7-8.3), (3.7-4.3), and (2.3-3.3) mm surrounding colonies on CCA, respectively. Further, these isolates were able to inhibit radial mycelium growth of the pathogen and were categorized into three antagonistic groups: 13 strong, 13 moderate, and 14 weak antagonists, with antibiosis inhibition Bones of (32.0-45.7), (22.7-31.3), and (3.7-22.3) mm, respectively. High levels of chitinase activity of the isolates Ma3 (8.3 mm), Jul (7.7 mm), and Sa8 (7.7 mm) with their antagonistic activity against mycelium growth of 45.7, 44.3, and 40.7 mm were observed, respectively. These isolates exhibited fungicidal activity against sclevotia of S. sclerotiorum. On the other hand, isolates Na5, Aj3, and Aj2 that produced no chitinase showed fungistatic effect only.

• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1519-1528
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• 2013

Bacillus pumilus SG2, a halotolerant strain, expresses two major chitinases designated ChiS and ChiL that were induced by chitin and secreted into the supernatant. The present work aimed to obtain a mutant with higher chitinolytic activity through mutagenesis of Bacillus pumilus SG2 using a combination of UV irradiation and nitrous acid treatment. Following mutagenesis and screening on chitin agar and subsequent formation of halos, the mutated strains were examined for degradation of chitin under different conditions. A mutant designated AV2-9 was selected owing to its higher chitinase activity. To search for possible mutations in the whole operon including ChiS and ChiL, the entire chitinase operon, including the intergenic region, promoter, and two areas corresponding to the ChiS and ChiL ORF, was suquenced. Nucleotide sequence analysis of the complete chitinase operon from the SG2 and AV2-9 strains showed the presence of a mutation in the catalytic domain (GH18) of chitinase (ChiL). The results demonstrated that a single base change had occurred in the ChiL sequence in AV2-9. The wild-type chitinase, ChiL, and the mutant (designated ChiLm) were cloned, expressed, and purified in E. coli. Both enzymes showed similar profiles of activity at different ranges of pH, NaCl concentration, and temperature, but the mutant enzyme showed approximately 30% higher catalytic activity under all the conditions tested. The results obtained in this study showed that the thermal stability of chitinase increased in the mutant strain. Bioinformatics analysis was performed to predict changes in the stability of proteins caused by mutation.

• Journal of Applied Biological Chemistry
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• v.43 no.4
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• pp.246-249
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• 2000

We investigated the production of chitin oligosaccharides using food grade papain. A solution of commercial food grade papain (FGP) was dialyzed for 12 h before measuring its chitinolytic activity. The effects of enzyme concentration, reaction temperature, and pH on the endochitinase and $\beta$-N-acetylglucosaminidase activities and the thermostability of these enzymes were investigated. In adddition, the reaction products were analyzed with gel filtration on a Bio-Gel P2. The endochitinase activity was twentyfold higher than that of $\beta$-N-acetylglucosaminidase. The optimal endochitinase activity was at pH 3.0, while the maximal $\beta$-N-acetylglucosaminidase activity was at pH 6.0. The reaction product consisted mainly of the dimer of N -acetylglucosamine, with a small amount of its trimer. Under the experimental conditions, $120{\mu}g$ of chitin oligomers were obtained with 1 mg of FGP protein after an incubation of 2 h.

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1312-1321
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• 2011

Enzyme extracts of cellulase [filter paper cellulase (FPase) and carboxymethyl cellulase (CMCase)], chitinase, and chitosanase produced by Aspergillus niger NRRL-567 were evaluated. The interactive effects of initial moisture and different inducers for FP cellulase and CMCase production were optimized using response surface methodology. Higher enzyme activities [FPase $79.24{\pm}4.22$ IU/gram fermented substrate (gfs) and CMCase $124.04{\pm}7.78$ IU/gfs] were achieved after 48 h fermentation in solid-state medium containing apple pomace supplemented with rice husk [1% (w/w)] under optimized conditions [pH 4.5, moisture 55% (v/w), and inducers veratryl alcohol (2 mM/kg), copper sulfate (1.5 mM/kg), and lactose 2% (w/w)] (p<0.05). Koji fermentation in trays was carried out and higher enzyme activities (FPase $96.67{\pm}4.18$ IU/gfs and CMCase $146.50{\pm}11.92$ IU/gfs) were achieved. The nonspecific chitinase and chitosanase activities of cellulase enzyme extract were analyzed using chitin and chitosan substrates with different physicochemical characteristics, such as degree of deacetylation, molecular weight, and viscosity. Higher chitinase and chitosanase activities of $70.28{\pm}3.34$ IU/gfs and $60.18{\pm}3.82$ to $64.20{\pm}4.12$ IU/gfs, respectively, were achieved. Moreover, the enzyme was stable and retained 92-94% activity even after one month. Cellulase enzyme extract obtained from A. niger with chitinolytic and chitosanolytic activities could be potentially used for making low-molecular-weight chitin and chitosan oligomers, having promising applications in biomedicine, pharmaceuticals, food, and agricultural industries, and in biocontrol formulations.

• Research in Plant Disease
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• v.21 no.3
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• pp.222-226
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• 2015

The chitinase-producing bacterial strain C-1 is one of the key chitinase-producing biocontrol agents used for effective bioformulations for biological control. These bioformulations are mixed cultures of various chitinolytic bacteria. However, the precise identification, biocontrol activity, and the underlying mechanisms of the strain C-1 have not been investigated so far. Therefore, we evaluated in planta biocontrol efficacies of C-1 and determined the draft genome sequence of the strain in this study. The bacterial C-1 strain was identified as a novel Serratia sp. by a phylogenic analysis of its 16S rRNA sequence. The Serratia sp. C-1 bacterial cultures showed strong in planta biocontrol efficacies against some major phytopathogenic fungal diseases. The draft genome sequence of Serratia sp. C-1 indicated that the C-1 strain is a novel strain harboring a subset of genes that may be involved in its biocontrol activities.

• BMB Reports
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• v.44 no.3
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• pp.193-198
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• 2011

The chitinase-producing strain SC081 was isolated from Korean traditional soy sauce and identified as Bacillus atrophaeus based on a phylogenetic analysis of the 16S rDNA sequence and a phenotypic analysis. A gene encoding chitinase from B. atrophaeus SC081 was cloned in Escherichia coli and was named SCChi-1 (GQ360078). The SCChi-1 nucleotide sequences were composed of 1788 base pairs and 596 amino acids, which were 92.6, 89.6, 89.3, and 78.9% identical to those of Bacillus subtilis (ABG57262), Bacillus pumilus (ABI15082), Bacillus amyloliquefaciens (ABO15008), and Bacillus licheniformis (ACF40833), respectively. A recombinant SCChi-1 containing a hexahistidine tag at the amino-terminus was constructed, overexpressed, and purified in E. coli to characterize SCChi-1. $H_6SCChi$-1 revealed a hydrolytic band on zymograms containing 0.1% glycol chitin and showed the highest lytic activity on colloidal chitin and acidic chitosan. The optimal temperature and pH for chitinolytic activity were $50^{\circ}C$ and pH 8.0, respectively.