Simultaneous production of low molecular weight chitosan and reducing sugar via high molecular chitosan depolymerization by surface discharge plasma

Chitosan is widely used in antibacterial, hypolipidemic, and anticancer fields, and the preparation of low molecular weight chitosan with excellent solubility and hydrophilicity is beneficial for its application. In this study, simultaneous production of low molecular weight chitosan and reducing sugars via chitosan depolymerization by surface discharge plasma was developed. More than 95% of the chitosan with an initial molecular weight of 682.5 kDa was depolymerized after 60 min of treatment, with the reducing sugar yield of 23.7%. .OH, O2.-, and 1O2 played important roles in chitosan depolymerization; they preferentially attacked the amorphous structure of chitosan, resulting in breakage of the intra- and intermolecular hydrogen bonds and beta-(1,4) glycosidic bonds, thereby forming low molecular weight chitosan. More electrons and hydrogen atoms would be provided by prepared low molecular weight chitosan due to the decreased intra- and intermolecular hydrogen bonds, and a high biological activity was finally attained. Overall, discharge plasma could be used as an effective technique for chitosan depolymerization, which widens its potential applications.

Automated summary

This study developed a method to simultaneously produce low molecular weight chitosan and reducing sugars through chitosan depolymerization by surface discharge plasma. Active oxygen species and radicals in the discharge plasma played important roles in degrading chitosan and forming low molecular weight chitosan, which ultimately increased its biological activity. Discharge plasma could be an effective technique for chitosan depolymerization, expanding its potential applications.