Effects of the halophilic fungi Cladosporium sphaerospermum, Wallemia sebi, Aureobasidium pullulans and Aspergillus nidulans on halite formed on sandstone surface

Abstract

This study presents a new method to clean up salts formed on the surface of sandstone found in the Medamoud (Nag al Medamoud) site in Egypt. The effects of the halophilic fungi Cladosporium sphaerospermum, Wallemia sebi, Aureobasidium pullulans and Aspergillus nidulans were studied on halite (NaCl) samples of deteriorated sandstone. X-ray diffraction (XRD), scanning electron microscopy (SEM), and total dilation salt (TDS) were employed to investigate sandstone samples treated with halophilic fungi under laboratory conditions. The analytical results confirmed that the salt concertation on the surface of sandstone blocks was lower for sandstone treated with fungi. Additionally, W. sebi, A. pullulans and A. nidulans were stimulated with 0, 5, 10, 15, 20 and 25% NaCl, and the treatment that most effectively increased the mycelial growth compared to the control was 5% NaCl. Furthermore, C. sphaerospermum grew best without NaCl. However, 25% NaCl completely inhibited mycelial growth. Mycelia of W. sebi grew to 24 mm on media containing 20% NaCl. The sodium salts stimulated growth in liquid culture. We observed that the effect of W. sebi on surface sodium chloride salts high consume and did not change colour from another fungi tested.