The use of Inappropriate Outdoor Exhibition method is one of the
main factors that accelerate the degradation of archaeological stone
works. Here, we describe and diagnosis the biodeterioration of
limestone water duct located in the courtyard of Sultan Qaitbay's
mosque (1475). The used exhibition method provides the suitable
environmental condition for biological grows. Several samples
taken from various colors of microbial biofilm on the water duct
surface were isolated and cultivated. The microorganisms were
documented and analyzed using optical light microscopy (OLM),
scanning electron microscopy with the energy dispersive X-ray
(SEM-EDX) and high performance liquid chromatography (HPLC).
The study showed that the main biofilm formers were fungi and
bacteria. The fungi were identified as: Aspergillus niger-
Aspergillus terrus – Acremonium sp. Alternaria sp. Paecilomyces
SP. Stemphylium. Two kinds of bacteria are present (Coccus – and
Bacillus). The organic acids produced by identified fungi were
qualitative and quantitative assessed. The degradation caused by the
identified microbial activities is discussed and the criteria for
archaeological stonework outdoor exhibition were presented