Polymerization degree-dependent changes in the effects of in vitro chitosan treatments on photosynthetic pigment, protein, and dry matter contents of Ipomoea purpurea

Crabs Marine Waste-A Valuable Source of Chitosan: Tuning Chitosan Properties by Chitin Extraction Optimization

Chitin extraction from crab shells was studied experimentally and optimized aiming to obtain chitosan with predefined deacetylation degree and molecular mass. To find out the optimum operating conditions that ensure the obtaining of a chitosan with highest deacetylation degree and specific molecular mass four parameters were varied: the concentration of NaOH and the temperature for deproteinization step, respectively HCl concentration and the number of acidic treatments for the demineralization stage. The experiment was carried on following Taguchi orthogonal array L9, and the best combination of factors was found using the desirability function approach. The optimization results showed that 5% NaOH concentration and low temperatures lead to a chitosan with high deacetylation degree. High molecular mass chitosan is obtained when a single step acidic treatment is used, while a chitosan with low molar mass is obtained for multiple acid contacts and higher HCl concentration.

Polymerization degree of chitosan affects structural and compositional changes in the cell walls, membrane lipids, and proteins in the leaves of Ipomoea purpurea: An FT-IR spectroscopy study

This research aimed to investigate the polymerization degree (DP) -dependent effects of chitosan treatments on structural and compositional changes in certain cell wall polysaccharides (mainly lignin), membrane lipids, and proteins of in vitro-propagated Ipomoea purpurea leaves through FT-IR spectroscopy. The chitosan oligomer mixture (DP 2-15; CHI-OM) and chitosan polymer (DP 70; CHI-P) applied at 5, 10, and 20 mg L^-1 concentrations induced different patterns of biomolecular changes in I. purpurea leaves. The chitosan variants enhanced the destabilization of cell membrane structures. CHI-P treatments increased the lipid structure and protein content of the membranes more than CHI-OM treatments. CHI-OM treatment was found to have the ability to induce the formation of β-sheet structures with a low number of strands, whereas CHI-P treatment was found to have the ability to trigger the formation of more extended α-helix structures in the secondary structure of proteins. CHI-P treatments increased lignin synthesis more than CHI-OM treatments. However, CHI-OM at 10 mg L^-1 concentration was more effective than CHI-P treatments in the induction of cell wall polysaccharide synthesis. These findings suggest that the polymerization degree of chitosan plays a role in changing structures and compositions of the biomolecules present in the leaves of I. purpurea.