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A total of 35 actinomycetes were isolated from the surface of mural paintings of snu- sort- ankh in El Leasht, Egypt during four seasons all over 2016-2017. In 2009 this tomb was deteriorated by "Aspergillus niger, A. flavus, Fusarium moniliforme, Alternaria alternate, Rhizopus stolonifera, Bacillus subtilis, Bacillus cereus, and micrococcus iuteus." In 2017 the isolation of swabs presents only Aspergillus niger and about 35 actinomycetes classified to three different groups "Streptomyces, Nocardia, and Micromonospora" only five species belong to Streptomyces group showed antimicrobial activity against the previous microorganisms. These actinomycetes were identified according to their sequences in the GenBank to "Streptomyces spectabilis, S. alborgriseolus, S. globsus, S. corchorstt, S. ambofactens." In the other hand, the pigments of the wall paintings of the tomb (Egyptian blue, Egyptian green, Goethite) that analyzed by SEM-EDX, FTIR were measured by the spectrophotometer in both 2009 and 2017. The results showed that the actinomycetes could produce extracellular pigments causing a color change of archaeological pigments otherwise it helps in inhibition the growth of the previous microorganisms found in 2009. The optimization factors for increasing the antibiotic production of the Streptomyces were 3% NaCl and temperature between 30:35°c in Alkin pH (pH = 7.5).

19 of Trichoderma spp. were isolated from the surface of Nefer bau betah mural paintings located in Giza plateau, Egypt. This tomb was previously deteriorated in 2007 by "Aspergillus niger, Aspergillus flavus, and Alternaria alternata as a most deteriorated fungus causing damage for these mural paintings" In 2019 the identification of microbes presented that the rate of Aspergillus niger growth decreased to 85% than the growth rate in 2007 and new 19 species of Trichoderma were isolated “that were not isolated before in 2007”. Three species of Trichoderma were identified according to their Bioactivity effect over Aspergillus niger, Aspergillus Flavus and Alternaria alternate and by their sequences in the GenBank to "Trichoderma harzianum, T. hamatum, and T. aureoviride." Furthermore, the pigments of the wall paintings of the tomb (Egyptian blue, Egyptian Green, Red Hematite) that were analyzed by SEM-EDX, Raman spectroscopy were essayed by the spectrophotometer. The results showed that the extracellular pigments have been produced by Trichoderma spp. causing a color change of archaeological pigments but in a safe range (less than 0.5%) otherwise, Trichoderma spp have the ability to inhibit the growth rate of the microorganisms that previously found in 2007. The optimization factors for increasing the bioactivity of the Trichoderma spp s were temperature between 30:35°c in acidic pH (pH=5.5) in the presents of sodium nitrate and sodium chlorine as salts deteriorated the tomb.

In this study, we report a novel approach for preparing precipitated calcium carbonate for the first time by Bacillus licheniformis using different types of media containing urea as a source of urease enzyme and for the first time using particles of pure calcium. The bacteria used in this study produced urease which catalyzes the hydrolysis of urea (CO(NH 2 ) 2 ) into ammonium (NH 4 ) and carbonate (CO 3 2− ) leading to the precipitation of calcium carbonate. Calcium carbonate precipitation was experimentally studied by spontaneous precipitation at various pH (8–12), temperatures (30, 35, 40, 45, 50 °C), and at different concentrations of urease enzyme (1, 5, 10 mg mL −1 ). The XRD results showed a mixture of calcite and vaterite. The morphology of calcium carbonate particles prepared was studied under SEM after using it as a bioconsolidation of degraded fresco wall paintings.

Bacterial-induced mineralization has been explored for protection and consolidation of degraded limestone, concrete and plaster by precipitation of calcium carbonate. It is the first time that Bacillus sphaericus was used for consolidating the nonsterilized decayed wall paintings samples by immersing them in sterile nutritional media. The B. sphaericus used in this study produced urease, which catalyzes the hydrolysis of urea (CO(NH2)2) into ammonium (NH4) and carbonate (CO3−2) leading to the precipitation of calcium carbonate. The effect of B. sphaericus on wall paintings was determined by recording the evolution of culture media chemistry and examining the treated wall paintings under a scanning electron microscope to show the structural and morphological evolution of calcium carbonate that was investigated in wall paintings models.