Biodeterioration

Biodeterioration refers to the unwanted alteration of materials caused by microorganisms—especially fungi—which damage both organic substrates (paper, wood, textiles) and inorganic ones (stone, plaster, glass). Unlike abiotic decay, biodeterioration results from biological activity that produces physical disruption and chemical degradation.

Physical deterioration occurs as fungal hyphae penetrate pores, cracks, and surface irregularities. Hyphal turgor pressure, thigmotropic growth along textured surfaces, and tunneling within substrates weaken structural integrity. In porous materials like stone or plaster, wet–dry cycles amplify microfractures. In organic substrates such as paper or wood, hyphae cause fiber separation and surface erosion.

Chemical deterioration arises from fungal metabolism. Hydrolytic enzymes—including cellulases, proteases, ligninases, and collagenases—break down organic polymers. Fungi also excrete organic acids (oxalic, citric, gluconic), which lower pH, dissolve minerals, and form secondary biominerals such as calcium oxalate crusts. Siderophores further solubilize metals, altering both the substrate and microbial ecology. Pigments such as melanins and quinones penetrate deeply into porous materials, causing often irreversible staining.

Biomineralization occurs when fungi precipitate minerals like oxalates or carbonates, which may fill pores and generate mechanical stress. In bone and ivory, fungal activity dissolves hydroxyapatite and facilitates reprecipitation of calcite or other minerals, increasing brittleness.

Fungi commonly exist within biofilms containing bacteria, algae, or lichens. These biofilms enhance adhesion, protect microbes from environmental stress, and support cooperative metabolism, often resulting in layered and progressive deterioration.

Material-specific impacts include pitting and crust formation on stone, cellulose and lignin decay in wood, collagen and cellulose degradation in paper and parchment, and acid-induced etching of glass and ceramics.

Prevention and remediation rely on environmental control (humidity, temperature, light), surface cleanliness, and minimal water exposure. When colonization occurs, identification via microscopy or DNA-based tools guides targeted antifungal or bioprotective treatments.