• The Plant Pathology Journal
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• v.32 no.3
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• pp.242-250
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• 2016

The aim of this study was to investigate antifungal activity of a range of different molecular weight (MW) chitosan against Penicillium italicum. Our results demonstrate that the antifungal activity was dependent both the MW and concentration of the chitosan. Among a series of chitosan derived from the hydrolysis of high MW chitosan, the fractions containing various sizes of chitosan ranging from 3 to 15 glucosamine units named as chitooligomers-F2 (CO-F2) was found to show the highest antifungal activity against P. italicum. Furthermore, the effect of CO-F2 toward this fungus was significantly reduced in the presence of $Ca^{2+}$, whereas its effect was recovered by ethylenediaminetetraacetic acid, suggesting that the CO-F2 acts via disruption of $Ca^{2+}$ gradient required for survival of the fungus. Our results suggest that CO-F2 may serve as potential compounds to develop alternatives to synthetic fungicides for the control of the postharvest diseases.

• Journal of Microbiology and Biotechnology
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• v.19 no.4
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• pp.358-361
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• 2009

The purified endochitosanase(Mw 41 kDa) from bacterium Bacillus cereus D-11 hydrolyzed chitooligomers $(GlcN)_{5-7}$ into chitobiose, chitotriose, and chitotetraose as the final products. The minimal size of the oligosaccharides for enzymatic hydrolysis was a pentamer. To further investigate the cleavage pattern of this enzyme, chitooligosaccharide alcohols were prepared as substrates and the end products of hydrolysis were analyzed by TLC and HPLC. The chitosanase split $(GlcN)_4GlcNOH$ into $(GlcN)_3+(GlcN)_1GlcNOH$, and $(GlcN)_5GIcNOH$ into $(GlcN)_4+(GlcN)_1GlcNOH$ and $(GlcN)_3+(GlcN)_2GlcNOH$. The heptamer $(GlcN)_6GlcNOH$ was split into $(GlcN)_5$ [thereafter hydrolyzed again into $(GlcN_3+(GlcN)2]+(GlcN)_1GlcNOH$, $(GlcN)_4+(GlcN)_2GlcNOH$, and $(GlcN)_3+(GlcN)_3GlcNOH$, whereas $(GlcN)_{1-3}GlcNOH$ was not hydrolyzed. The monomers GlcN and GIcNOH were never detected from the enzyme reaction. These results suggest that D-11 chitosanase recognizes three glucosamine residues in the minus position and simultaneously two residues in the plus position from the cleavage point.

• 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.

• 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.