New Functionalized Chitosan with Thio-Thiadiazole Derivative with Enhanced Inhibition of Pathogenic Bacteria, Plant Threatening Fungi, and Improvement of Seed Germination

In this study, a new modified chitosan conjugate (Chito-TZ) was developed via amide coupling between the acid chloride derivative of methylthio-thidiazole compound and free primary amino groups chitosan. The product characterized using several instrumental investigations, including Fourier-transform infrared spectroscopy (FT-IR), 1H-Nuclear magnetic resonance, X-ray photoelectron (XPS), thermogravimetric analysis (TGA), diffraction (XRD). XRD indicated that crystalline pattern interrupted after chemical modification with thiadiazole derivative. Broido’s model used to determine thermal activation energy Ea, results showed Ea for first decomposition region Chito-TZ is 24.70 KJ mol−1 lower than required (95.57 mol−1), indicating accelerating effect on Chito-TZ. better antibacterial antifungal activities non-modified chitosan; except seed germination, better. low MIC value (25–50 µg mL−1) compared Chito (50–100 mL−1). Moreover, maximum inhibition percentages plant-pathogenic fungi, Aspergillus niger, Fusarium oxysporum, solani, were attained at concentration 300 mL−1 values 35.4 ± 0.9–39.4 1.7% 45.2 1.6–52.1 1.3% highest germination (%) broad bean, shoot root length weight, vigor index obtained treatment 200