The suitability of different substrates for Bacillus sp. R2 chitinase activity was tested on various crude and purified chitinous substrates, as well as chitinase storage stability was studied weekly for 2 months at three different temperatures (25, 4 and -20°C). The results revealed that chitinase enzyme of Bacillus sp. R2 catalyzed the hydrolysis of various chitinous substrates, and exhibited greater activity towards the chitins β of Calmar and squid. The temperature -20ºC was the most appropriate temperature for chitinase storage where the enzyme exhibited a relative resistance to freezing and thawing conditions, where its live 4 cycles (4 weeks) with missing 30% from the initial activity. On the other hand, at the temperatures 4 and 25ºC the enzyme retained 43.6% and 44.9% of its initial activity after the first month and 12% and 27.6 after the second month. Concerning the antifungal activity, the chitinase enzyme displayed a mild effect against many saprophytic and plant pathogenic fungi according the descending order: Aspergillus niger > Penicillium degitatum> Aspergillus flavus > Fusarium calmorum > Penicillium sp. >Macrophomira sp. > Rhizoctonia solani. This type of studies characterizes the enzyme for potential pharmaceutically important chitooligosaccharides preparation or promising antifungals production.
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