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Despite their threatens for Egyptian stone monuments, A few studies focused on using biocontrol agents against deteriorative fungi and bacteria instead of using chemical assays that leave residuals leading to human toxicity and environmental pollution. This work aims to isolate and identify fungal and bacterial isolates that showed deteriorative activities from stone monuments in Temple of Hathor, Luxor, Egypt, as well as determine the inhibitory activity of metabolites produced by Streptomyces exfoliatus SAMAH 2021 against the identified deteriorative fungal and bacterial strains. Moreover, studying the spectral analysis, toxicological assessment of metabolites produced by S. exfoliatus SAMAH 2021 against health human cell fibroblast, and colorimetric measurements on the selected stone monuments. Ten samples were collected from Temple of Hathor, Luxor, Egypt. Three fungal isolates and one bacterial isolate were obtained and identified as A. niger isolate Hathor 2, C. fioriniae strain Hathor 3, P. chrysogenum strain HATHOR 1, and L. sphaericus strain Hathor 4, respectively. Inhibitory potential of the metabolites in all concentrations used (100–25%) against the recommended antibiotics (Tetracycline 10 µg/ml and Doxycycline (30 µg/ml) showed an inhibitory effect toward all tested deteriorative pathogens with a minimum inhibition concentration (MIC) of 25%. Cytotoxicity test confirmed that microbial filtrate as the antimicrobial agent was safe for healthy human skin fibroblast with IC50 of < 100% and cell viability of 97%. Gas chromatography analysis recorded the existence of thirteen antimicrobial agents, Cis-vaccenic acid; 1,2-Benzenedicarboxylic acid; ç-Butyl-ç-butyrolactone and other compounds. Colorimetric measurements confirmed no color or surface change for the limestone-treated pieces. The use of the metabolite of microbial species antimicrobial as a biocontrol agent raises contemporary issues concerning the bio-protection of the Egyptian monuments to reduce chemical formulas that are toxic to humans and pollute the environment. Such serious problems need further investigation for all kinds of monuments.

Despite their threatens for Egyptian stone monuments, A few studies focused on using biocontrol agents against deteriorative fungi and bacteria instead of using chemical assays that leave residuals leading to human toxicity and environmental pollution. This work aims to isolate and identify fungal and bacterial isolates that showed deteriorative activities from stone monuments in Temple of Hathor, Luxor, Egypt, as well as determine the inhibitory activity of metabolites produced by Streptomyces exfoliatus against the identified deteriorative fungal and bacterial strains. Moreover, studying the spectral analysis, toxicological assessment of metabolites produced by S. exfoliatus against health human cell fibroblast (HCF), and colorimetric measurements on the selected stone monuments. Ten samples were collected from Temple of Hathor, Loxor, Egypt. Four fungal isolates and one bacterial isolate were obtained and identified as A. niger isolate Hathor 2, C. fioriniae strain Hathor 3, P. chrysogenum strain Hathor 1, and L. sphaericus strain Hathor 4, respectively. Inhibitory potential of the metabolites in all concentrations used (100–25%) against the recommended antibiotics (Tetracycline 10 µg/ml and Doxycycline 30 µg/ml) showed an inhibitory effect toward all tested deteriorative pathogens with a minimum inhibition concentration (MIC) of 25%. Cytotoxicity test confirmed that S. exfoliatus filtrate as the antimicrobial agent was safe for healthy human skin fibroblast with IC50 of < 100% and cell viability of 97%. Gas chromatography (GC) analysis recorded the existence of thirteen antimicrobial agents, Cis-vaccenic acid; 1,2-Benzenedicarboxylic acid; ç-Butyl-ç-butyrolactone and other compounds. Colorimetric measurements confirmed no color or surface change for the limestone-treated pieces. The use of S. exfoliatus antimicrobial as a biocontrol agent raises contemporary issues concerning the bio-protection of the Egyptian monuments to reduce chemical formulas that are toxic to humans and pollute the environment. Such serious problems need further investigation for all kinds of monuments.

Biosynthesis of green nanomaterials using microorganisms is considered clean, eco-friendly and viable, instead of the physical or chemical methods. This study aimed in the biosynthesis of copper nanoparticles (CuNPs) exploiting Egyptian local bacterial isolates. Sixteen copper-resistant isolates out of 160 bacterial isolates; were captured from various plant rhizospheres including; chamomile, hibiscus, neem, iris, and pea, beside samples collected from the Sharm El-Sheikh seawater. Among the 16 copper-resistant isolates, one promising isolate I108 was chosen which synthesized CuNPs of diameter about 87.1 nm, showed UV absorbance of 0.54 at 580 nm, with a concentration of 12.21 mg\ l. This isolate was characterized by phenotypic and genotypic features. Based on 16S rRNA gene analysis and compared with the sequences presented in NCBI GenBank, the phylogeny positions assessment confirmed that it belonged to Genus Pseudomonas, and was closely related to Pseudomonas silesiensis strain A3 (98% similarity). For the bacterial synthesis of CuNPs, optimization of the P. silesinsis strain A3 cell-free supernatant was carried out using seven agro-industrial residues, added to the basal medium as different carbon sources. Results showed that 2% blackstrap sugar cane molasses was the most efficient carbon source for CuNPs biosynthesis, when incubated for at 30°C for 24 h using shaking speed of 120 rpm. The biosynthesized CuNPs has a size of 66.12 nm at a concentration of 19.2 mg\ l, and maximum surface plasmon peak (SPR) of 0.85.

According to their special physio-chemical properties, Nanoparticles have gained worldwide attention as a new bio-alternative for chemical control agents. This investigation aims to the eco-friendly synthesis of nanosilver particles from tomato peel extract (TPE-AgNPs) and evaluates their characteristics and inhibitory activities against pathogenic bacteria and fungi as well as their role in metallic surface disinfecting. To initiate biosynthesis, tomato peel extract was mixed with silver nitrate (AgNO3) solution until the color changes to reddish brown. Ultraviolet (UV-Visible) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, and transmission electron microscopy (TEM) techniques were used to characterize biosynthesized TPE-AgNPs. Results recorded that obtained TPE-AgNPs had a strong score (238nm) of Plasmon resonance (SPR) by SPR of 4.5. Functional groups of carboxyl, hydroxyl, and phenolic groups existed and were detected by the FTIR spectrum. The synthesized TPE-AgNPs had an amorphous nature which was confirmed by XRD analysis. TEM analysis showed spherical TPE-AgNPs sized from 4.44-27.59nm. The biosynthesized TPE-AgNPs had a negative zeta potential of -68.44 mV. The inhibitory activities of synthesized TPE-AgNPs were evaluated against eleven microbial pathogenic using well diffusion method, inhibition zone diameter (IZD) was measured in centimeters. Results showed that B. subtilis and E.coli was the most sensitive pathogens with IZD of 4.0 and 0.92cm, respectively However, L. monocytogenes and S. sonnei were the most resistant pathogens with IZD of 0.92 and 0.90 cm, respectively. Synthesized TPE-AgNPs from tomato peels had good inhibitory potentials against pathogenic fungi with IZD of 3.0 and 0.92cm against A. solani and C. albicans, respectively. Applying the use of TPE-AgNPs as bio disinfectant significantly decreased the microbial load of metallic blades and proves its efficiency as a disinfectant agent after 120min. of contacting. So, more applications on disinfecting metallic surfaces such as dentistry are indeed needed.