Isolation and Characterization of Neoscytalidium dimidiatum ITD-G6 from Agave durangensis Leaves for Enhanced Cellulase Production in Solid-State Cultivation

Abstract

The cellulase production strategy considers the selection of microorganisms and the best experimental conditions for fermentation. This work describes the molecular identification of a fungus isolated from Agave durangensis, employing the internal transcribed spacer 18 S rRNA gene, located in the small subunit 28 S rRNA gene, belonging to a larger subunit, elongation factor 1-α, and the β-tubulin sequences. The best experimental conditions for improving cellulase production using A. durangensis leaves as a solid-state fermentation substrate were also evaluated. A profile of enzymatic activity of endoglucanase (Endo-β), exoglucanase (Exo-β), and β-glucosidase (β-g) obtained at 96 h is presented. Sequences used in the identification analysis of the isolated fungus identified it as a phytopathogen species of Neoscytalidium dimidiatum ITD-G6, belonging to the Botryosphaeriaceae family. To the authors’ awareness, this is the first report where leaves of A. durangensis are hosts of this microorganism. The maximum enzymatic activities were obtained at 72 h (2.78 ± 0.015 IU/mL) and 96 h (3.44 ± 0.017 IU/mL), under 37 °C, pH = 4.5, and 70% humidity. At these conditions, the cellulolytic activity of the three enzymes was as follows: Endo-β (0.0547 ± 0.0167 IU/mL), Exo-β (0.0163 ± 0.001 IU/mL), and β-g (0.0692 ± 0.07 IU/mL). The data presented suggest that the isolated fungus has biotechnological potential as a source of cellulases, contributing to the field of little-studied phytopathogens, owing to the feasibility of biomass conversion.