Induced Chitinase and Chitosanase Activities in Turmeric Plants by Application of β-D-Glucan Nanoparticles

The chitinase and chitosanase activities after β-D-glucan nanoparticle (GNP) application turmeric plants (leaves and rhizomes) were measured. Foliar spray of GNP (0.1%, w/v) elicited marked an increase in the activity levels of chitinases and chitosanases. Such a growth of enzyme activities was enhanced by subsequent spraying GNP on turmeric leaves at regular intervals. Application of β-D-glucan nanoparticles enhanced the level of defense related enzymes in leaves and rhizomes, which correlated well with new isoforms of the enzymes. Qualitative differences in isoforms of these defense enzymes were investigated during the hereby time-course study. In general, the expression of chitinase activity was comparatively lower in rhizomes than in leaves. Chitinase and chitosanase activity reached maximum values during the 7th month. Exploiting the nanoparticle (derived from natural polysaccharide) potential may refer to induce defense enzymes that may diminish the use of toxic chemicals for disease control. Thus the use of nanoparticles could be proposed as an alternative, non-conventional and ecologically friendly approach for plant protection and hence for sustainable agriculture.

Screening, Identification of a Marine Fungal Strain Producing Chitosanase

For the production of oligosaccharides from chitosan, chitosanase-producing strains were screened from local marine mud by clear zone formed on the chitosanase-detection agar (CDA) plate. More than 20 kinds of strains with clear zones on the CDA plates were obtained, including bacteria, actinomyces, and fungi. Among them a marine fungal strain N-8 was screened and chosen because of its prominent chitosanase activity. On the basis of the morphological characteristics and sequence analysis of 26S rDNA of strain N-8, the marine fungal strain N-8 was identified as the species Aspergillus flavus strain.

Chitosanase production by Paenibacillus ehimensis and its application for chitosan hydrolysis

The chitosanase production by Paenibacillus ehimensis was studied in submerged cultures and the chitosan hydrolysis was evaluated by using these enzymes without purification. The bacterium produced inducibles enzymes after 12 h of growth in a culture medium containing 0.2% (w/v) of soluble chitosan as carbon source. The enzyme production was strongly repressed by the presence of glucose. The production started as soon as the available sugars finished in the culture medium. The maximum level of chitosanase activity was 500 U.L-1 at 36°C after 36 h incubation. The crude enzyme was optimally active at pH 6.0 and 55°C and in these conditions, the enzyme presented good stability (6 days). The enzyme without purification was used to hydrolyze the chitosan which resulted chitooligosaccharides between 20 and 30 min of reaction.