Molecular Identification of Spoilage Fungi Isolated from Fruit and Vegetables and Their Control with Chitosan

This study investigated fungal spoilage of fruits and vegetables in Saudi Arabia. Activities of cell wall degrading enzymes in fungal isolates were measured. We evaluated the fungicidal activities of chitosan against spoilage fungi. Thirty-three fungal species belonged to 21 fungal genera were collected during this study. ITS sequencing results showed that Alternaria tenuissima, Fusarium chlamydosporum, Penicillium sumatrens, Rhizopus stolonifera, and Trichoderma harzianum were the most common species. The diversity of cell wall degrading enzyme produced by the spoilage fungi revealed that xylanase was the most widely distributed enzyme in fungi followed by amylase and cellulase. Some strains of Macrophomina phaseolina, Trichoderma harzianum, Trichoderma asperellum, Aspergillus niger and Alternaria consortialis showed the highest enzymes activities among tested fungi. Four different concentrations of chitosan (20, 30, 50, and 100 mg/L) were investigated against 22 fungal species. All investigated concentrations of chitosan showed highly significant reduction in the average of radial growth of all tested fungi.