Enzymatic dynamics and chemical transformation in Dendrocalamus sinicus biodeterioration by typical filamentous fungi

Abstract

<i>Dendrocalamus sinicus</i>, the world's largest bamboo species, is valued for its high strength and rapid growth, finding extensive application in construction, furniture, and composite materials. However, mold-induced deterioration impairs the visual appearance, chemical stability, and structural integrity, thereby compromising service performance and lifespan. This study aimed to elucidate the multi-scale deterioration mechanisms of <i>Dendrocalamus sinicus</i> under colonization by <i>Aspergillus niger</i>, <i>Penicillium citrinum</i>, and <i>Trichoderma viride</i>. It was found that the deterioration efficiency depended critically on the spatiotemporal overlap between lignin-degrading enzyme and hydrolase activities. Hemicellulose was the primary and preferentially attacked component by all three molds. Distinct enzymatic pathways drive mold-specific cellulose-lignin biodeterioration. <i>Aspergillus niger</i> employed an inward-to-outward cellulose-prioritized pathway, <i>Penicillium citrinum</i> executed a surface-oriented lignin-prioritized degradation, and <i.Trichoderma viride</i> simultaneously decomposed cellulose and lignin. Microstructural erosion followed a continuous three-stage pattern commencing with colonization and consumption of readily decomposable substances, progressing to enzymatic deconstruction of cell walls, causing a sharp increase in porosity, and culminating in structural collapse. These mechanistic insights provide novel targets for developing species-tailored preservation technologies, which are essential for extending the service life of bamboo products and promoting the value-added conversion of bamboo resources within a circular economy framework.