Functional Differentiation and Structural Disruption of Agave tequilana Bagasse by Lignocellulolytic Fungi Under Sterile and Non-Sterile Substrate Conditions

Agave bagasse is a lignocellulosic residue generated after the extraction of fermentable sugars from agave hearts during tequila production. More than 0.5 million tons are generated annually, accumulating on a massive scale and posing a serious environmental challenge. In this regard, the objective of this study was to evaluate the degradative capacity of Trametes versicolor (Tv), Trametes hirsuta (Th), Irpex lacteus (Il), and Schizophyllum commune (Sc) on Agave tequilana Weber variety azul bagasse through the analysis of total sugars, cellulose, hemicellulose, and lignin reduction in a solid-static treatment. Under sterile conditions, Tv reduced total sugars by 95.0%, Th by 89.5%, Il by 91.8%, and Sc by 74.6%; whereas under non-sterile conditions, reductions were 81.6%, 71.4%, 84.9%, and 64.7%, respectively. Regarding structural fractions under sterile conditions, Tv showed reductions of 67.8% in cellulose, 61.9% in hemicellulose, and 68.8% in lignin. Th achieved 62.8%, 58.8%, and 66.1%, respectively; Il exhibited the highest values, with 72.9%, 66.9%, and 74.6%; while Sc recorded 55.9%, 44.2%, and 61.0%. In contrast, reductions were lower under non-sterile conditions: Tv recorded 57.8%, 34.2%, and 62.2%; Th, 53.9%, 32.1%, and 59.6%; Il, 58.8%, 47.1%, and 64.7%; and Sc, 49.9%, 30.0%, and 56.5%. Overall, sterile substrate conditions maximized lignocellulosic degradation; however, the sustained activity observed under non-sterile conditions demonstrates that effective biological pretreatment can be achieved without sterilization, which is more relevant for large-scale solid-state fermentation. The results demonstrate that T. versicolor and I. lacteus possess high potential as biological pretreatment agents by accelerating the depolymerization of the lignocellulosic matrix. This effect could reduce composting times and enable applications that favor its inclusion in circular economy frameworks.