Evaluation of sulfonated oxidized chitosan antifungal activity against Fusarium graminearum

Abstract

Chitosan biomaterials are widely used in the biological area because of their broad-spectrum antibacterial activity. However, chitosan cannot be dissolved in a neutral solution, limiting its application in various fields seriously. In this study, water-soluble sulfonated oxidized chitosan (SOCS) with antifungal activity were prepared by oxidization and sulfonation. Its structure was clearly confirmed by spectroscopy data (FTIR, 1H NMR, ¹³C NMR) and elemental analysis. SEM images of OCS and SOCS revealed that there was a little curly and an irregular sheet-like morphologies on them which was attributed to the oxidation and sulfonation on CS. Moreover, the FTIR and NMR indicated that –OH on the CS was oxidized into -COOH on the OCS and -SO₃H groups on the SOCS. The EDS results of OCS and SOCS confirmed the presence of the oxygen element in OCS and the S element in SOCS. All studies confirmed the OCS and SOCS were synthesized successfully. Furthermore, the inhibitory activity of SOCS biocomposites against plant pathogenic fungi, (Fusarium graminearum), was investigated. The results showed that the SOCS have significant inhibitory effects on the mycelial growth of F. graminearum. The EC₅₀ value of SOCS against F. graminearum is 79.46 μg/mL. The research results presented above indicated that SOCS can be used as a candidate material for the control of plant pathogenic fungi, and can broaden the application of chitosan materials in plant protection and sustainable agriculture.

Research highlights

• SOCS showed better solubility in deionized water.

• The antifungal effect of SOCS dissolved in acetic acid was higher than that of CS dissolved in acetic acid.

• SOCS dissolved in water can cause an inhibitory effect on F. graminearum at lower concentrations.

Keywords:

• Chitosan derivative
• biomaterials
• sulfonation reaction
• Fusarium graminearum

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was funded by National Natural Science Foundation of China (Grant No. 31501680 and Grant No. 31771735), Key Research and Development Program of Hebei Province (Grant No. 1326507D), Natural Science Foundation of Hebei Province (Grant No. B2018407058), Scientific Research Foundation of Hebei Normal University of Science and Technology (Grant No. 2021YB002), Marine Science Research Program of Hebei Normal University of Science and Technology (Grant No. 2018HY009) and Postgraduate Innovation Funding Project of Hebei Province (Grant No. CXZZSS2022096).