Production and physicochemical properties of fungal chitosans with efficacy to inhibit mycelial growth activity of pathogenic fungi

In order to enable the applicability of chitosan as an antifungal, soil fungi were isolated and identified, then used in its production. Fungal chitosan has several advantages, including lower toxicity, low cost, and high degree of deacetylation. These characteristics are essential for therapeutic applications. The results indicate high viability of the isolated strains to produce chitosan, obtaining a maximum yield of 40.59 mg chitosan/g of dry biomass. M. pseudolusitanicus L. was reported for the first time for production by chitosan. The chitosan signals were observed by ATR-FTIR and 13C SSNMR. Chitosans showed high degrees of deacetylation (DD), ranging from 68.8% to 88.5%. In comparison with the crustacean chitosan, Rhizopus stolonifer and Cunninghamella elegans presented lower viscometric molar masses (26.23 and 22.18 kDa). At the same time, the molar mass of chitosan Mucor pseudolusitanicus L. showed a value coincident with that assumed as low molar mass (50,000–150,000 g mol−1). Concerning the in vitro antifungal potential against the dermatophyte fungus Microsporum canis (CFP 00098), the fungal chitosans showed satisfactory antifungal activities, inhibiting mycelial growth by up to 62.81%. This study points to the potential of chitosans extracted from fungal cell walls for applications in the inhibition of the growth of (Microsporum canis) human pathogenic dermatophyte.