Abstract
Aspergillus niger LOCK 62 produces an antifungal chitinase. Different sources of chitin in the medium were used to test the production of the chitinase. Chitinase production was most effective when colloidal chitin and shrimp shell were used as substrates. The optimum incubation period for chitinase production by Aspergillus niger LOCK 62 was 6 days. The chitinase was purified from the culture medium by fractionation with ammonium sulfate and affinity chromatography. The molecular mass of the purified enzyme was 43 kDa. The highest activity was obtained at 40 °C for both crude and purified enzymes. The crude chitinase activity was stable during 180 min incubation at 40 °C, but purified chitinase lost about 25 % of its activity under these conditions. Optimal pH for chitinase activity was pH 6–6.5. The activity of crude and purified enzyme was stabilized by Mg2+ and Ca2+ ions, but inhibited by Hg2+ and Pb2+ ions. Chitinase isolated from Aspergillus niger LOCK 62 inhibited the growth of the fungal phytopathogens: Fusarium culmorum, Fusarium solani and Rhizoctonia solani. The growth of Botrytis cinerea, Alternaria alternata, and Fusarium oxysporum was not affected.
Highlights
Chitinases (E.C. 3.2.1.14.) are enzymes that are capable of hydrolyzing chitin to its oligomers and/or monomers
Chitinase isolated from Aspergillus niger LOCK 62 inhibited the growth of the fungal phytopathogens: Fusarium culmorum, Fusarium solani and Rhizoctonia solani
The aim of the present study was to determine the potential of Aspergillus niger LOCK 62 chitinase
Summary
Chitinases (E.C. 3.2.1.14.) are enzymes that are capable of hydrolyzing chitin to its oligomers and/or monomers. Chitinase from various origins has different enzymological properties and usually constitutes a complex chitinolytic enzyme These enzymes play an important role in the nutrition and parasitism of bacteria and fungi. The search for microorganisms antagonistic toward fungi has intensified due to the fact that they are causative factors of many plant diseases This is usually associated with the production of antifungal compounds and extracellular hydrolytic enzymes (chitinase and 1,3-bglucanase) [21]. The excessive use of these compounds, which has increased almost threefold over the past 40 years, has led to problems related to contamination and degradation of the natural environment These substances can be lethal to beneficial insects and microorganisms in the soil, and may enter the food chain [5]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
