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.

No abstract

The rapid growth of the human population in recent decades has resulted in the intensive development of various industries, the development of urban agglomerations and increased production of medicines for animals and humans, plant protection products and fertilizers on an unprecedented scale. Intensive agriculture, expanding urban areas and newly established industrial plants release huge amounts of pollutants into the environment, which, in nature, are very slowly degraded or not decomposed, which leads to their accumulation in water and terrestrial ecosystems. Researchers are scouring extremely contaminated environments to identify organisms that have the ability to degrade resistant xenobiotics, such as PAHs, some pharmaceuticals, plasticizers and dyes. These organisms are a potential source of enzymes that could be used in the bioremediation of industrial and municipal wastewater. Great hopes are pinned on oxidoreductases, including laccase, called by some a green biocatalyst because the end product of the oxidation of a wide range of substrates by this enzyme is water and other compounds, most often including dimers, trimers and polymers. Laccase immobilization techniques and their use in systems together with adsorption or separation have found application in the enzymatic bioremediation of wastewater.

No abstract