%0 Journal Article
%T Production of a Thermostable and Alkaline Chitinase by Bacillus thuringiensis subsp. kurstaki Strain HBK-51
%A Secil Berna Kuzu
%A Hatice Korkmaz G¨¹venmez
%A Aziz Akin Denizci
%J Biotechnology Research International
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/135498
%X This paper reports the isolation and identification of chitinase-producing Bacillus from chitin-containing wastes, production of a thermostable and alkaline chitinasese, and enzyme characterization. Bacillus thuringiensis subsp. kurstaki HBK-51 was isolated from soil and was identified. Chitinase was obtained from supernatant of B. thuringiensis HBK-51 strain and showed its optimum activity at 110¡ãC and at pH 9.0. Following 3 hours of incubation period, the enzyme showed a high level of activity at 110¡ãC (96% remaining activity) and between pH 9.0 and 12.0 (98% remaining activity). Considering these characteristics, the enzyme was described as hyperthermophile-thermostable and highly alkaline. Two bands of the enzyme weighing 50 and 125£¿kDa were obtained following 12% SDS-PAGE analyses. Among the metal ions and chemicals used, Ni2+ (32%), K+ (44%), and Cu2+ (56%) increased the enzyme activity while EDTA (7%), SDS (7%), Hg2+ (11%), and ethyl-acetimidate (20%) decreased the activity of the enzyme. Bacillus thuringiensis subsp. kurstaki HBK-51 is an important strain which can be used in several biotechnological applications as a chitinase producer. 1. Introduction Chitin, a linear ¦Â-(1,4)-linked N-acetylglucosamine (GlcNAc) polysaccharide, is the main structure component of the fungal cell wall and the exoskeletons of invertebrates, such as insects and crustaceans. Chitinase plays a variety of important roles in these organisms ranging from nutrition to defense and control of ecdysis in insects. The importance of chitinases in many biological processes makes their inhibitors important targets for potential antifungal and insecticidal agents as well as antimalarial agents [1]. It is one of the most abundant naturally occurring polysaccharides and has attracted tremendous attention in the fields of agriculture, pharmacology, and biotechnology. Chitin is the second most abundant component of biomass on earth [2]. This linear polymer can be hydrolyzed by bases, acids or enzymes, such as lysozyme, some glucanases, and chitinase. Chitinases (EC 3.2.1.14), essential enzymes catalyzing the conversion of chitin to its monomeric or oligomeric components (low-molecular-weight products), have been found in a wide range of organisms, including bacteria, plants, fungi, insects, and crustaceans. Because chitin is not found in vertebrates, it has been suggested that inhibition of chitinases may be used for the treatment of fungal infections and human parasitosis [3]. Biological control, using microorganisms to repress plant disease, offers an alternative environmentally
%U http://www.hindawi.com/journals/btri/2012/135498/