Microbial dynamics, chemical profile, and bioactive potential of diverse Egyptian marine environments from archaeological wood to soda lake

Halophilic archaea are a unique group of microorganisms that thrive in high–salt environments, exhibiting remarkable adaptations to survive extreme conditions. Archaeological wood and El–Hamra Lake serve as a substrate for a diverse range of microorganisms, including archaea, although the exact role of archaea in archaeological wood biodeterioration remains unclear. The morphological and chemical characterizations of archaeological wood were evaluated using FTIR, SEM, and EDX. The degradation of polysaccharides was identified in Fourier transform infrared analysis (FTIR). The degradation of wood was observed through scanning electron microscopy (SEM). The energy dispersive X–ray spectroscopy (EDX) revealed the inclusion of minerals, such as calcium, silicon, iron, and sulfur, into archaeological wood structure during burial and subsequent interaction with the surrounding environment. Archaea may also be associated with detected silica in archaeological wood since several organosilicon compounds have been found in the crude extracts of archaeal cells. Archaeal species were isolated from water and sediment samples from various sites in El–Hamra Lake and identified as Natronococcus sp. strain WNHS2, Natrialba hulunbeirensisstrain WNHS14, Natrialba chahannaoensis strain WNHS9, and Natronococcus occultus strain WNHS5. Additionally, three archaeal isolates were obtained from archaeological wood samples and identified as Natrialba chahannaoensisstrain W15, Natrialba chahannaoensisstrain W22, and Natrialba chahannaoensisstrain W24. These archaeal isolates exhibited haloalkaliphilic characteristics since they could thrive in environments with high salinity and alkalinity. Crude extracts of archaeal cells were analyzed for the organic compounds using gas chromatography–mass spectrometry (GC–MS). A total of 59 compounds were identified, including free saturated and unsaturated fatty acids, saturated fatty acid esters, ethyl and methyl esters of unsaturated fatty acids, glycerides, phthalic acid esters, organosiloxane, terpene, alkane, alcohol, ketone, aldehyde, ester, ether, and aromatic compounds. Several organic compounds exhibited promising biological activities. FTIR spectroscopy revealed the presence of various functional groups, such as hydroxyl, carboxylate, siloxane, trimethylsilyl, and long acyl chains in the archaeal extracts. Furthermore, the archaeal extracts exhibited antioxidant effects. This study demonstrates the potential of archaeal extracts as a valuable source of bioactive compounds with pharmaceutical and biomedical applications.

. Plates were incubated at the appropriate temperature for halophilic archaea growth (usually around 37 °C).The colonies showing distinct morphologies were selected and subcultured onto fresh high-salt agar plates to obtain pure cultures 17 (Figs. 1, 2).

Archaeological wood structural evaluation
The wood structural assessment in archaeological contexts was conducted utilizing two distinct methodologies: Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM).Each technique necessitated specific preparatory measures to ensure optimal analysis.For the FTIR analysis, wood samples were subjected to air-drying, subsequently fragmented into small pieces, and then subjected to nitrogen purification to eliminate any residual particulate matter and wood debris.The resulting wood powder (2 mg) was mixed with potassium bromide (KBr) (200 mg) to form thin tablets under compression.Spectral analysis spanning the 4000-400 cm −1 region was performed using a PerkinElmer FTIR spectrometer, employing parameters of 16 scans and a resolution of 4 cm −1 .SEM micrograph analysis entailed the utilization of a JSM IT200 scanning electron microscope equipped with a Secondary Electron Imaging (SEI) detector.Sample preparation for SEM involved dehydration via the Critical Point Dryer technique followed by gold coating.Prior to imaging, wood samples were embedded in Spurr resin and sectioned to ultra-thin dimensions (≤ 90 nm thick) using an ultra-microtome.Subsequent imaging was conducted at an accelerating voltage of 15 kV.Energy-dispersive X-ray spectroscopy (EDX) was employed for elemental analysis at selected regions of interest, utilizing a SED detector at a voltage of 20 kV and a working distance of 10 mm.Elemental composition within the SEM-observed sections was determined through this analytical approach.Additionally, elemental data was obtained through combustion analysis utilizing the ELTRA Elemental Analyzer-CHN device 19,20 .

Preparation of archaeal crude extracts
The extraction was performed by soaking the isolated dried archaeal biomass (1: 20 w/v) in a methanol/chloroform mixture (1:1).The extract was filtered using Whatman No. 4 filter paper after being shaken for 48 h at 25 °C and 120 rpm in the dark.The pellet was repeatedly suspended in another amount of solvent.The supernatants were combined.The collected solvent was evaporated under vacuum with reduced pressure until it was completely dry, and the resulting residue, or crude extract, was then sealed in airtight bottles and kept at -20 °C until needed.

Fourier transform infrared spectroscopy (FT-IR)
For pellets preparation, the crude extract was mashed with KBr and roughly pulverized in a mortar at a ratio of 1/100.Using a model Perkin Elmer FT-IR spectroscopy, the infrared spectra of dry extracts were examined for functional groups in the 400-4000 cm -1 wave number range under normal conditions.

Gas chromatography-mass spectrometry (GC-MS)
The chemical constituents of archaeal cell extracts were analyzed by Agilent GC-MS (Agilent model 7890A-5975USA) equipped with an autosampler and fused-silica capillary column (DB 5MS 30 m, 0.25 mm, 0.25 μm).The injector was maintained at 200 °C using the splitless injection mode, and the injections were made at 1 μl volume.The temperature was maintained at 40 °C for 2 min then elevated to 100 °C followed by an increase to 140 °C at 2 °C/min, and finally an increase to 340 °C at 30 °C/min.The total run time was 20 min.Helium was the carrier gas at a flow rate of 0.9 ml/min.The chemical components of the archaeal cell extracts were identified (de-convoluted) using the retention indices of the GC chromatogram and the fragmentation pattern of the mass spectra by matching with the Wiley spectral library collection and the NSIT library database.

Total antioxidant capacity of archaeal crude extracts
The total antioxidant activity was measured using 21 method.A green phosphate/Mo(V) complex is formed as a result of the extract's reduction of Mo(VI) to Mo(V)in acidic medium.Two millilitres of the reagent solution (0.6 M sulfuric acid, 28 mM sodium phosphate, and 4 mM ammonium molybdate) were mixed with a portion (0.6 ml) of the extracts.Test tubes were incubated at 95 °C in a water bath for 90 min.All samples were tested for absorbance at 695 nm against a blank after the samples had cooled to room temperature.The antioxidant capacity was given as µM ascorbic acid equivalent per gram of dry weight (µM/gdry wt).

Chemical and structural evaluation of archaeological wood
Infrared analysis of archaeological wood sample Chemical and structural evaluation of archaeological wood.Infrared analysis of archaeological wood sample.
The anoxic conditions seen in submerged environments greatly slow down degradation processes, which are mostly driven by anaerobic biological organisms.Using enzymatic breakdown, these organisms specifically target polysaccharides, with hemicelluloses being especially susceptible 22 .Since lignin has a very solid structure, it is typically thought to be far more resistant to biological deterioration.Archaeological wood is frequently marked by a high lignin concentration due to the preferred degradation of celluloses, with celluloses sometimes totally depleted 20 .While the majority of FTIR absorbance peaks are the result of several molecules, some can only be ascribed to cellulose, hemicelluloses, or lignin, as a result, they may be investigated to reveal the relative presence of each component 23 .The degree of decay is indicated by changes in the relative composition of archaeological wood as compared to fresh wood as well and the comparison of distinct peaks within the same spectrum renders the analysis semi-quantitative.The FT-IR spectra acquired from both historical and fresh samples are illustrated in Fig. 3. Within the historical specimens, notable spectral features are observed within specific wavenumber ranges.For instance, bands within the spectral region of 1000-1180 cm -1 , indicative of stretching and asymmetric vibrations attributed to C-O, C-C, and C-O-C functionalities, alongside the band at 1375 cm -1 corresponding to symmetric and asymmetric bending of CH 3 groups, are associated with the presence of cellulose and hemicellulose constituents.Additionally, a discernible reduction in the spectral intensity within the 1245 cm -1 region, indicative of carbohydrates and lignin, is noted.Consequently, a significant decline is observed in the 1730 cm -1 region, associated with the stretching of C = O bonds in xylan, a component of hemicellulose.Moreover, in higher frequency regions spanning 2800-3400 cm -1 , attributed to C-H and OH functionalities, a substantial decrease in spectral intensity is observed, further indicating alterations in cellulose and hemicellulose content.Conversely, an increase in spectral intensity at 1505 cm -1 , corresponding to the stretching vibrations of aromatic C = C bonds in lignin, is evident, likely attributed to the loss of extractives and carbohydrates.Table 1 illustrates the peak assignments for the FTIR spectrum of archaeological wood [24][25][26][27][28] .

FTIR analysis of the archaeal extracts
The seven archaeal extracts were characterized by FT-IR spectroscopy to identify the various functional groups.The range of the FT-IR absorption peaks was predominantly between 4000 cm −1 and 400 cm −1 .Different crude  .Moreover, the presence of Si-CH 3 bonds is suggested by the absorption peak at about 1255 cm −131 .The bending vibrations of (-C-H) in the CH 2 and CH 3 groups of lipids and pigments as well as the stretching vibrations of C-N in molecules containing nitrogen (such as indole) were identified as responsible for the occurrence of vibrations at approximately 1400 cm −1 and 1350 cm −126 .A strong absorption peak about 650 cm −1 (Fig. 1S) can be observed, which suggests that a C-Cl or C-I bond is present 30 .This agrees with the chemical compounds obtained through GC-MS.These findings supported the GC-MS quantification data and further demonstrated that the crude extracts include organic silicon, ethers, organic acids, esters, and alcohols, among other substances.

Morphological feature of archaeological wood using scanning electron microscopy (SEM)
In wet conditions, the cellulose-depleted cell walls fill with water instead, preserving the wood's structural integrity 22 .Even though it is relatively stable, lignin may deteriorate.Nevertheless, when dried, this lignin-rich skeleton is an extremely brittle substance that is readily collapsed or warped by force 22 .As a result, the sample tended to collapse during the phases of preparation and microscopy, which had an impact on the SEM observations.The flattened and irregularly shaped wood cells in the current study are indicative of a significant degree of shrinkage upon drying, which is typical of deteriorated wood.The cell walls of archeological wood are much thinner than those of sound wood.This poor condition of preservation is confirmed by the SEM image shown in Fig. 4.This provides a clarification for the breakdown of carbohydrates detected by FT-IR measurements.

Energy-dispersive X-ray spectroscopy (EDX) and elemental analysis of archaeological wood sample
During its deposition and burial, archaeological wood is exposed to a range of chemical and biological degradation processes, which produces a material that differs greatly from fresh wood in terms of its chemical composition and structure.The chemical composition of wet archaeological wood can be altered chemically as a result of exchange with the surrounding burial chamber.Since many "extractives" dissolve in water, they are either eliminated or present in much-decreased amounts.The great porosity of the wood, on the other hand, allows minerals from the burial environment, such as calcium, phosphates, and iron sulfides, to gradually seep into the cell walls, increasing the inorganic, or "ash," content.Because minerals are incorporated over time into the wood structure through interchange with the burial environment, a larger amount of inorganic components can also be a sign of decomposition 16 .SEM observation at 15 kV with a SEI detector revealed the presence of various inorganic depositions (Figs.4,5).The presence of calcium (~ 7%), silicon (~ 7%), and iron (~ 21%) was detected by EDX analysis.Moreover, several organosilicon compounds are present in the extracts of archaea species that were isolated from archaeological samples in the current study.The literature reports that throughout the wood's burial history, the process of progressive fossilization, also known as synoptic petrification or permineralization, has occurred.This was accompanied by the buildup of minerals, including silicates (SiO 2 ) and calcium carbonate (CaCO 3 ) 25 .Analyses also showed the presence of oxygen (~ 52%), which is the main element in wood, and the absence of carbon.Moreover, other elements were found, including sodium (~ 0.4%), potassium (~ 0.4%), titanium (~ 0.4%), magnesium (~ 1%), phosphorus (~ 2%), manganese (~ 2%), aluminum (~ 3%), and chloride (~ 0.4%).Inorganic components can affect conservation procedures and introduce measurement errors for wood   www.nature.com/scientificreports/density and maximum water content, among other things.Consequently, determining the inorganic composition is a crucial step in evaluating wet archaeological wood 22 .When compared to recently submerged wood, the elemental makeup of the archaeological wood showed a lack of carbon and nitrogen, which verifies the EDX results (Table 3).It reflects the alterations and transformations undergone by the wood during the fossilization process.Archeological wood can still provide valuable information about past ecosystems and geological history.

Isolation and molecular identification of different archaeal strains
In this study, four archaeal isolates were recovered from water and sediment samples collected from different sites at El-Hamra Lake, Wadi El-Natrun and identified as Natronococcus sp.strain WNHS2 (A1) (AC, KP788716), Natrialba hulunbeirensis strain WNHS14 (A2) (AC, KP765047), Natronococcus occultus strain WNHS5 (A3) (AC, KP861849), Natrialba chahannaoensis strain WNHS9 (A4) (AC, KP828442).This lake provides a highly saline and extreme environment, making it an ideal habitat for halophilic archaea.The lake's high salt concentration and unique geochemical conditions offer a suitable niche for the survival and proliferation of these specialized halophilic archaea.In addition, three archaeal isolates from archaeological wood samples, Natrialba chahannaoensis strain W15 (A5) (AC, PP177495), Natrialba chahannaoensis strain W22 (A6) (AC, PP177494), and Natrialba chahannaoensis strain W24 (A7) (AC, PP177490) were selected for further investigation.All the archaea isolates were haloalkaliphilic since they could thrive in environment with high salinity and alkalinity.The biodegradation of wood, in which microorganisms break down lignin, cellulose, and hemicellulose to release carbon dioxide, water, and mineral components, is a component of the natural carbon cycle.In general, many diverse species, including fungus, bacteria, protozoa, worms, and nematodes, are involved in decomposition 24 .
Hence, archaeological wood is a substrate for a wide range of microorganisms, which exist in very complex ecosystems, where interactions are possible, not only between the microorganisms, but also with other organisms.Furthermore, within the microbiota of decaying wood, microorganisms such as archaea have also been found, and clones belonging to the phyla of Thaumarchaeota, Crenarchaeota, and Euryarchaeota were identified as members of this archaeal community.However, it is still questionable whether archaea actually affects the biodeterioration of wood 32 .

Gas chromatography-mass spectrometry analysis of archaeal crude extracts
The dried cells of seven archaeal species were extracted using solvents to produce various crude extracts to offer information that may serve as a reference for the pharmaceutical sector about the applicability of bioactive chemicals from archaeal biomass.All archaeal fractions were examined for their organic compounds using GC-MS.59 compounds were approximately identified by GC-MS and categorized in Table (3) according to structural criteria as follows: free saturated and unsaturated fatty acids (5), saturated fatty acid esters (2), ethyl and methyl esters of unsaturated fatty acids (3), glycerides (5), phthalic acid esters (5), organosiloxane (12), terpene (3), alkane (5), alcohol (4), ketone (1), aldehyde (1), ester (11), ether (1), and aromatic (1) compounds.Numerous biological activities have been associated with the main organic compounds identified in archaeal biomass (Table 4).Cyclopropanemethanol, 2-methyl-2-(4-methyl-3-pentenyl)-, is one of the organic compounds with antibacterial and antifungal action found in crude extract of A7 isolated from archaeological wood 33 .Crude extracts of A4, A5, A6, and A7 cells have been shown to contain pentanoic acid, 5-hydroxy, 2,4-di-t-butylphenyl ester, an aromatic compound with antibacterial and anticancer activities 33,34 .Indole, another aromatic substance detected in all archaeal extracts except A1, was previously thought to be a typical contaminant in agricultural and industrial wastewater and recently was identified as a versatile signalling molecule with a broad environmental distribution.Indole has been the subject of an increasingly expanding number of studies due to its important involvement in bacterial physiology, pathogenicity, animal behaviour, and human.Numerous bacterial species have tryptophanases that may convert tryptophan to indole.Due to the diversity of environmental niches occupied by indole-producing bacteria, indole may be present in a broad range of environments, including activated sludge, soil, plant rhizospheres, the ocean, and animal and animals waste.The indole nucleus is widely employed in the pharmaceutical industry because it offers a broad range of biological actions, including anticancer, antiviral, antibacterial, anti-inflammatory, anti-HIV, and antidiabetic effects 35 .Furthermore, through interacting with the aryl hydrocarbon receptor, indole has been shown to be able to prolong health span (stay healthy and free of age-related ailments) in animals 36 , underlining the future potential of indoles as novel treatments to enhance life quality and lessen frailty.Cyclononasiloxane, octadecamethyl-was one of the polysiloxane derivatives found in the crude extract of A7 archaeal cells isolated from archaeological wood.According to reports, this substance has antioxidant [38]and antifungal properties 37 .Other polysiloxane derivatives that showed antibacterial and anticancer activities are 3-butoxy-1,1,1,7,7,7-hexamethyl-3,5,5-tris(trimethylsiloxy)tetrasiloxane [40]and hexasiloxane tetradecamethyl40], respectively.Moreover, 3-Isopropoxy-1,1,1,7,7,7-hexamethyl-3,5,5-tris(trimethylsiloxy) tetrasiloxane has been proved to be potential lead molecules for antimicrobial agent using molecular docking study 38 .Heptasiloxane, hexadecamethyl-shows activity against various target www.nature.com/scientificreports/medical and agronomic pests according to 39 .Hexasiloxane, 1, , a siloxane derivative, functions as an emollient, solvent, antibacterial, antiseptic, and skin-and hair-conditioning agent 40 .Phthalic acid esters, a group of extensively used lipophilic compounds used as plasticizers and additives, are one of the substances that have been identified in the current study.Because of their unique chemical compositions, phthalate esters are frequently employed as synthetic materials in the production of paints, textiles, personal care www.nature.com/scientificreports/products, cosmetics, and polymers.These materials have noteworthy hazardous effects 41 .The natural origin of phthalate compounds has been shown by a study on the 14 C di-butyl phthalate level found in edible brown and green seaweeds 41 .The occurrence of phthalate esters as physiologically active secondary metabolites in plants, animals, and microbes has been noted in an increasing number of investigations 41 .Some species of freshwater algae and cyanobacteria are capable of producing di-n-butyl phthalate and mono (2-ethylhexyl) phthalate, according to 42 .Allelopathic, antibacterial, insecticidal, and other documented biological properties of PAEs may increase the competitiveness of plants, algae, and microorganisms to better withstand biotic and abiotic stress 43 .
In the current investigation, phthalic acid, dibutylester (A1&A3), phthalic acid, diisooctyl ester (A2&4), phthalic acid, dodecyl nonyl ester (A5), phthalic acid, cyclobutyltridecyl ester (A6), and phthalic acid, mono(2-ethylhexyl) ester (A6&7) were found in GC-MS of different archaeal samples.The first report of phthalic acid, dodecyl nonyl ester, and cyclobutyltridecyl ester has been recorded in archaeal crude extracts isolated from archaeological wood samples.Di-n-butyl phthalate, a potent inhibitor of α-glucosidase, was isolated from Streptomyces melanosporofaciens, claiming by 44 .Additionally, theisolated pure phthalic acid, mono(2-ethylhexyl) ester obtained from marine-derived actinomycete Streptomyces sp.VITSJK8's shown cytotoxic action against HepG2 and MCF-7 cancer cell lines 45 .Phthalic acid diisooctylester, one of the detected PAEs, was previously isolated from the drug-producing plant Gloriosasuperba 46 .It can be used as an antifouling and antibacterial agent 47 .The contribution of fatty acids in crude extracts, another class of aroma compounds, was due to saturated fatty acid (n-hexadecanoic acid; octadecanoic acid; eicosanoic acid; valeric acid, 4-tridecyl ester;triacontanoic acid, methyl ester; ethyl 9-hexadecenoate) and unsaturated fatty acid (cis-vaccenic acid; oleic acid; 9-octadecenoic acid (Z)-, methyl ester; 11,14-eicosadienoic acid, methyl ester).In addition, esters of glycerol with fatty acids were found in crude extracts of archaeal cells including hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl)ethyl ester;octadecanoic acid, 2,3-dihydroxypropyl ester;octadecanoic acid, 2-hydroxy-1,3-propanediyl ester; 9-octadecenoic acid, 1,2,3-propanetriyl ester; (E,E,E)-,1-Monolinoleoylglycerol trimethylsilyl ether.The pharmacological effects of this class of chemicals include antibacterial, hypolipidemic, insecticide, herbicide, anticancer, antioxidant, immunological modulators, and antispasmodic properties (Table 4).They might also be added to meals and utilised as cosmetics (Table 3).For example, Venkatramanan et al.(2020) examined the use of hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester in the treatment of Chromobacterium violaceum infections using docking score and molecular research 48 .It is obvious from the docking score and molecular dynamic investigations that this chemical binds to the CviR receptor, which suggests that it may be utilised to treat C. violaceum infections due to its anti-QS and antibiofilm properties.One of the significant monocyclic sesquiterpenes identified in all archaeal cell extracts except for A1is α-bisabolol, also known as levomenoli, is generated naturally from the essential oils of several edible and decorative plants.Numerous laboratory investigations have shown that bisabolol has pharmacological features that include anticancer, antinociceptive, neuroprotective, cardioprotective, and antibacterial effects.Furthermore, due to its skin-soothing properties, α-bisabolol has been utilized as a skin conditioning agent and is included in many cosmetic compositions 49 .Another volatile terpenoid identified in A2 crude extracts with antileishmanial properties is geranylgeraniol 49 .Squalene, another significant triterpene, is widely utilized in the cosmetics industry as an anti-wrinkle agent 50 and as an anticancer, antioxidant, drug carrier, and detoxifier activities 51 found in archaeal crude extracts except for A1 and A3.

Antioxidant activity
Different halophilic archaeal strains showed anti-oxidant effect.The examined strains showed antioxidant effect in which Natrialba chahannaoensis strain W15 was recorded the highest antioxidant activity being 90.60 µM/g followed by Natrialba hulunbeirensisstrain WNHS14 (68.43 µM/g), Natrialba chahannaoensis-strainW22 (17.84 µM/g), Natronococcus sp.strain WNHS2 (17.30 µM/g), Natrialba chahannaoensisstrain WNHS9(17.18µM/g), Natrialba chahannaoensis strainW24(16.65µM/g), and Natronococcus occults strain WNHS5 (12.90 µM/g) crude extractsin the present study compared to control.The halophilic archaea are microorganisms that thrive in extreme environments characterized by high salt saturation, elevated temperatures, and intense UV radiation.These microorganisms have garnered interest due to the unique properties of their molecules, which exhibit remarkable tolerance to salt and heat, as well as potent antioxidant capabilities.Consequently, they serve as an excellent resource for various biotechnological applications.However, compared to other groups such as plants or algae, which are commonly recognized for their beneficial effects on health, the bioactive properties of haloarchaea have received limited attention.Therefore, Gómez-Villegas et al. (2020) presented the isolation and molecular identification of two novel haloarchaeal strains obtained from Odiel salterns in southwestern Spain.Furthermore, he investigated the antioxidant, antimicrobial, and bioactive potential of extracts derived from these strains.The findings of this research demonstrate that acetone-based extracts exhibit the highest levels of activity in anti-oxidant, anti-microbial, and anti-inflammatory assays 10 .Consequently, these extracts hold significant promise as a source of metabolites with practical applications in the fields of pharmacy, cosmetics, and the food industry.Also Ma et al., 2018 demonstrated the antioxidant activity of the carotenoids which extracted from haloarchaeon Halorubrum sp.HRM-150 isolated from brine water 35 .Also, Hou & Cui, 2018 indicated the anti-inflammatory, anti-oxidant, and anticancer activity of carotenoids extracts from 7 haloarchaea strains Haloferax volcanii, Halogranum rubrum, Halopelagius inordinatus, Haloplanus vescus, Haladaptatus litoreus, Halogeometricum limi, and Halogeometricum rufum.In the context of aqueous protein-rich extracts, there is currently a lack of existing reports that can be used for comparison specifically pertaining to haloarchaea 11 .The observation that various extracts derived from the studied archaea exhibit antioxidant activity suggests the presence of diverse antioxidant compounds with varying characteristics and polarities in haloarchaea.It is common for polyphenolic compounds to be associated with the antioxidant activity found in extracts from brown algae 74,75  www.nature.com/scientificreports/ the antioxidant capabilities of haloarchaea are primarily attributed to the presence of carotenoid pigments 76 .Nevertheless, when considering all the results collectively, they suggest that extracts from haloarchaea hold great potential as a source of antioxidant compounds that can be applied in various fields such as natural food preservation, coloration, and supplementation 77 , as well as sources of cosmetic and pharmaceutical formulations to avoid cell oxidative damage 78 (Table 5).

Conclusion
All isolated archaea were haloalkaliphilic since they could thrive in environment with high salinity and alkalinity.In this study, four archaeal isolates were recovered from water and sediment samples collected from different sites at El-Hamra Lake, Wadi El-Natrun and identified as Natronococcus sp.strain WNHS2 (AC, KP788716), Natrialba hulunbeirensis strain WNHS14 (AC, KP765047), Natrialba chahannaoensisstrain WNHS 9 (AC, KP828442) and Natronococcus occultus strain WNHS5 (AC, KP861849).In addition, threearchaeal isolates, Natrialba chahannaoensis strain W15 (AC, PP177495), Natrialba chahannaoensis strain W22 (AC, PP177494), and Natrialba chahannaoensisstrain W24 (AC, PP177490) were identifiedfrom archaeological wood samples.The presence of archaea within the microbiota of decaying wood has been reported, but their exact role in wood biodeterioration is still not fully understood.The chemical and morphological characterizations of archaeological wood were evaluated using FTIR, SEM, EDX, and combustion analysis.The FTIR analysis shows that hemicellulose, the main component of carbohydrates, degrades more than lignin.Microscopic observations of archaeological wood using SEM reveal significant changes in cell structure and morphology compared to sound wood.The presence of inorganic components, such as calcium, silicon, iron, and sulfur, has been detected through EDX and combustion analyses.Exchange with the burial environment results in the incorporation of minerals into the wood structure, increasing the inorganic content.Notably, diatoms have been reported to be related to the presence of silica in archeological wood.Archaea may also be associated with detected silica in archaeological wood since several organosilicon compounds have been found in the crude extracts of archaeal cells.In addition, the crude extracts obtained from dried cells of seven archaeal species have been analyzed using GC-MS and FTIR to identify bioactive compounds with potential pharmaceutical applications.A total of 59 compounds (A1; 13 compounds, A2; 21 compounds, A3; 22 compounds, A4; 19 compounds, A5; 23 compounds, A6; 22 compounds, and A7; 22 compounds) were identified and categorized into different structural groups.Several organic compounds exhibited promising biological activities, including antibacterial, antifungal, anticancer, anti-inflammatory, antiviral, and antioxidant effects.Overall, these findings provide valuable insights into the potential of bioactive compounds derived from halophilic archaeal biomass for pharmaceutical applications.

Fig. 2 .
Fig. 2. Flow chart diagram of sample collection and preparation.

Table 1 .
Peak assignments for FTIR spectrum of archaeological wood.

Table 2 .
Bands assignment of FTIR spectra to their corresponding functional groups in different archaeal crude extracts.

Table 3 .
Elemental composition of archaeological wood.

Table 4 .
Biological activities associated with the main organic compounds identified in archaeal

Table 5 .
Total antioxidant capacity of archaeal crude extracts.