Cyanobacterial Sulfate Accumulation from Black Crust of a Historic Building

Abstract

The cyanobacterium Gloeothece PCC 6909 was cultured in BG 11₀ medium supplemented with gypsum black crusts removed from the cathedral of Seville, Spain. The sulfate released to the medium due to gypsum dissolution was progressively incorporated into the carbohydrate sheath and used for balanced growth. Therefore, the gypsum black crust served as a continuous source of sulfate for the cyanobacterium, suggesting that gypsum may have a role in the cyanobacteria colonization of blackened monuments in urban environments.