Table 2.

Microorganisms and environmental factors involved in biodeterioration of architectural buildings and artworks (Source: Dakal and Cameotra, 2012).

Microbial group	Microorganisms/environmental factors	Deterioration type	Mechanism
Photoautotrophs	Cyanobacteria	Esthetic and chemical deterioration	Biofilm, color alteration, patina, crust formation, bioweathering
	Lichen	Chemical and mechanical deterioration	Extraction of nutrients from stone surface, oxalate formation, carbonic acid production, physical intrusions
	Algae	Esthetic and chemical deterioration	Biofilm, color alteration, black crusts
	Mosses and Liverworts	Esthetic and chemical deterioration	Discoloration, green gray patches, extraction of minerals
Chemoautotrophs	Sulfur oxidizing, Nitrifying bacteria	Chemical deterioration	Black custs
Chemoheterotrophs	Heterotrophic bacteria	Esthetic and chemical deterioration	Crust formation, patina, exfoliation, color alteration
	Actinomycetes	Esthetic deterioration	Whitish gray powder, patina, white salt efflorescence
	Fungi	Esthetic, chemical, physical and mechanical deterioration	Fungal diagenesis, color alteration, oxalate formation, bioweathering, physical intrusions, destabilization of stone texture
Chemoorganotrophs	Sulfur reducing bacteria	Chemical deterioration	Conversion of sulfate to sulfite
Higher plants	Higher plants	Mechanical deterioration	Intrusion of roots in cracks, pores leading to collapse and detachment of stone structure