Partial purification and characterization of chiIO8, a novel antifungal chitinase produced by Bacillus cereus IO8

Abstract

Aims: To investigate the distribution of chitinase IO8 in Bacillus cereus strains, the enhancing effects of the chitinase-producing B. cereus strains on biocontrol potential by dual culture assay and in vivo assay against Botrytis cinerea and also the enhancing effects of the chiIO8 on disinfectant properties against seedborne diseases. Moreover, the application of chiIO8 treatment was also observed to improve the germinative energy. Methods and Results: The purification steps included ammonium sulfate precipitation, with columns of DEAE-Sepharose anion-exchange chromatography and Sephacryl S-400 high-resolution gel chromatography. The method gave a 5Á8-fold increase in the specific activity and had a yield of 17%. The molecular weight of the partially purified chitinase chiIO8 was found to be around 30 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal pH and optimal temperature of the partially purified chitinase were pH 6Á5 and 65°C, respectively. The thermostable chitinase still retained the activity after incubation for 100 min at 65°C, and it was increased about 1Á25 times than that of the control (before heating) when the enzyme solution heated at 65°C for 60 min. The partially purified chitinase chiIO8 displays a wide inhibitory spectrum towards all phytopathogenic fungi tested. chiIO8 also exhibited effective disinfectant properties against seed-borne diseases. Conclusion: The present investigation emphasizes the potential of chitinaseproducing micro-organism as promising biocontrol agents of fungal plant pathogens with chitinous cell wall. The novel chitinase chiIO8 proved an efficient, environmentally safe and user-friendly solution. Significance and Impact of the Study: This is the first investigation devoted exclusively to analyse the distribution of chitinase in B. cereus. It infers that the chitinase produced by B. cereus might play a role in the activity of the biopesticide.

Purification and biochemical characterization of novel acidic chitinase from Paenicibacillus barengoltzii

“…They have received a great deal of attention in recent years due to their biotechnological applications in different fields [3]. They can be used in the production of N-acetyl GOSs [4] and GlcNAc [5] in food or pharmaceutical industry [2], bioconversion of chitin materials to ethanol in energy industry [6], production of single cell protein in feed industry [7] and bio-controlling of fungal phytopathogens in agriculture [8,9].…”

Purification, biochemical characterization and antifungal activity of a novel Aspergillus tubingensis glucose oxidase steady on broad range of pH and temperatures

“…In addition, the applications of biological control have been extensively used for plant growth promotion and disease control. Right now, natural antifungal products such as plant-based essential oils and extracts [8], peptide [9] and enzymes [10] are proved to be successful and an effective strategy for controlling various plant diseases. The enzymes may be effective, biodegradable, selective and less toxic to the environment as well as to food and agriculture industries.…”

Isolation, partial characterization, and cloning of an extracellular chitinase from the entomopathogenic fungus Verticillium lecanii

“…Recently, a purified chitinase from Stenotrophomonas maltophilia, a bacterium that is antagonistic toward fungal phytopathogens, was shown to inhibit the growth of fungal phytopathogens belonging to the genera Fusarium, Rhizoctonia, and Alternaria (Jankiewicz et al, 2012). A purified chiIO8 from Bacillus cereus exhibited activity against Botrytis cinerea in an in vivo assay (Hammami et al, 2013). A genetic transformation and expression system for temporal and spatial regulation of gene expression has been established in V. lecanii to facilitate the study of gene function in vivo.…”

“…Chitin is one of the highest b-1,4-Nacetyl-d-glucosamine-containing units in nature after cellulose. This molecule provides architectural reinforcement of biological structures, such as insect exoskeletons, crustacean shells, higher fungal cell walls, and other biological matrices involved in protection and self-defense (Hammami et al, 2013). Chitin is also a well-known pathogen-associated molecular pattern that elicits plant immunity.…”