This paper provides a review of the latest research findings on the applications of microbial chitinases to biological control. Microorganisms producing these enzymes can inhibit the growth of many fungal diseases that pose a serious threat to global crop production. Currently, efforts are being made to discover producers of chitinolytic enzymes. The potential exists that natural biofungicides will replace chemical fungicides or will be used to supplement currently used fungicides, which would reduce the negative impact of chemicals on the environment and support the sustainable development of agriculture and forestry.

No abstract

No 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.

SUMMARY This paper presents the results of the study on the production of protease by Bacillus luteus H11 isolated from an alkaline soda lime. B. luteus H11 was identified as an alkalohalophilic bacterium, and its extracellular serine endoprotease also showed an extreme alkali- and halotolerance. It was remarkably stable in the presence of NaCl up to 5 M. The enzyme was active in a broad range of pH values and temperatures, with an optimum pH of 10.5 and a temperature of 45 °C. It had a molecular mass of about 37 kDa and showed activity against azocasein and a synthetic substrate for the subtilisin-like protease, N-succinyl- l -phenylalanine- p -nitroanilide. The halo-alkaline protease produced by B. luteus H11 seems to be significant from an industrial perspective because of its tolerance towards high salinity and alkalinity as well as its stability against some organic solvents, surfactants and oxidants. These properties make the protease suitable for applications in food, detergent and pharmaceutical industries, and also in environmental bioremediation.