1 Introduction

Different materials, including paper, wood, cellulose, and leather, that are widely used in libraries and archives, are suffering from biodeterioration caused by fungi [1]. Fungi are the main deterioration agents that affect wood, historical manuscripts, leathers, wood products, paper, and other heritage artifacts. They consume and degrade the polysaccharide components and cause the degradation of the cell walls or the discoloration of organic materials [2,3,4]. They have a remarkable ability to produce extracellular hydrolytic enzymes, which cause severe damage to valuable documents, and produce pigments or weak acids, resulting in the discoloration, disfigurement, and staining of these materials [5, 6].

Paper, which is a source of organic carbon for many microorganisms, is used to manufacture objects such as books, prints, and documents [7, 8]. It contains several organic substances such as inks, vegetable or animal glues, fillers, and pigments, which are sources of nutrition to various microorganisms and can augment its biodegradability [7,8,9,10].

Cotton linters (CLs), a byproduct from cotton seeds after cotton fiber harvesting, are short, thick-walled, curly, much less costly [11, 12], and an alternative and renewable source for cellulosic materials for paper manufacturing worldwide [13]. Some varieties of Egyptian cotton have long fibrous linters with a length average varying from 10 to 40 mm contaminated with higher amounts of impurities such as mineral matter (12–16% based on dry weight) [14, 15].

CLs contain α-cellulose as the main compound with the proteinaceous matter, pectin, waxes, and ash [16]. CL fibers are composed of pure cellulose and, therefore, could provide higher-quality regenerated cellulose than wood fibers [17]. When using CLs as raw materials for regenerated cellulose, milder pulping and bleaching processes are recommended over wood. These processes are very important for removing impurities and increasing paper brightness, as well as for adjusting the polymerization degree of cellulose [17].

Furthermore, fungi are responsible for the enzymatic degradation of cellulosic textile substrates such as linen and flax [18, 19]. Enzymes produced by fungi are functionalized to decrease the degree of polymerization while damaging the structure of the fibers and leading to loss of strength [20]. The degradation rate also depends on other parameters, such as the degree of orientation or substitution and the presence of non-cellulosic substances [21].

Parchment, the thin material made from animal skin (e.g., sheep and goat), has widely been used for writing from the second century BC until the end of the Middle Ages until it was replaced by paper in Europe [22, 23]. Parchment is treated with lime, while leather is mostly tanned and, therefore, is more sensitive to fluctuations in relative humidity and, subsequently, deteriorated by fungi [24]. Collagen fibers and proteinaceous structures of parchment can be hydrolyzed, and their inorganic components can be modified by microorganisms, resulting in parchment discolored by pigments and organic acids and indirectly damaged [25, 26]. Proteolytic fungi can easily develop on ancient parchment and hydrolyze collagen fibers [27]. Under high humidity conditions, microorganisms can easily develop on leather and furs; for this reason, they are particularly vulnerable to deterioration [28,29,30].

To maintain and store these valuable materials, it is urgent to control the active fungal growth and remove or reduce the number of fungal ascospores and conidia [31,32,33,34]. Thus, using appropriate treatment measures for contaminated objects is challenging for restorers, curators, and scientists [35]. Therefore, to prevent the biodeterioration caused by fungi, materials must first be disinfected. The requirements for a disinfectant include the ability to inhibit the growth and metabolic activity of microorganisms without adversely affecting the material. Currently, fumigation with ethylene oxide is the most popular method for disinfecting fabrics, papers, and leather [36, 37]. However, this gas is an irritant and a dangerous human carcinogen, and its use should be avoided [38].

Recently, in the manufacturing of industrial materials, several additives have been used to improve the quality of the product or increase its durability against fungal infestation. Eco-friendly additives such as natural plant extracts, including phenolic and flavonoid compounds [39,40,41] and essential oils (EOs), are used to increase the resistance of these materials against mold infestations [42].

Bioactive compounds are used against microorganisms that grow on papers and textiles and have become highly important for bio-functionalization with safe, non-toxic, and environment-friendly properties [3, 43,44,45,46]. EOs from medicinal and aromatic plants have shown different biological activities when applied to different materials such as wood, paper, and textiles [34, 41, 47, 48]. EOs have been applied to combat the biodeterioration process in cultural heritage as an eco-friendly solution [49].

Furthermore, the disinfection process using EOs requires a long time, so this work aimed to find a way to accelerate this.

Therefore, this work was carried out to use and evaluate two essential oils from Pinus rigida wood and Origanum majorana leaves as eco-friendly additives to some industrial materials (cotton linter paper pulp, linen textile, and parchment) against fungal infestation.

2 Materials and methods

2.1 Cotton linters paper

2.1.1 Preparation of cotton linters samples and their chemical characterizations

The Egyptian cotton linter fibers (CLs) used in this work were provided by the Holding Company for Spinning and Weaving, El-Mahalla El-Kubra, Egypt. The CL samples were supplied free of seeds as the local company typically separates the linters from the seeds. Linters were chopped, fractionated using a knife mill, screened, cut to between 2 and 3 cm long, and homogenized in single lots.

Approximately 20 g of CLs were ground into a powder in a Culatti micro-impact mill type grinder (Model MFC, CZ13; ZENITH, Zurich, Germany) with a 1 mm screen, and the fraction passing through a 40-mesh size but retained on a + 60-mesh size was used for chemical analysis. The chemical characterizations of CLs were conducted as per TAPPI standard test methods. The tests that were carried out included: solubility in alcohol/benzene (1:2 v/v) solvent extraction (TAPPI T 204 cm-07) [50], acid-insoluble lignin (TAPPI T 222 om-21) [51], and pentosans as per TAPPI T 223 cm-10 [52]. For α-cellulose (gravimetric method), holocelluloses, and ash content, the following methods were used TAPPI T 203 cm-09 [53], TAPPI T 249 cm-21 [54], and TAPPI T 211 om-16 [55], respectively. Four samples were used for each chemical characterization. All results were reported as percentages of the initial weight of CLs.

2.1.2 Kraft pulping process of cotton linters

Samples of 200 g of oven-dried CLs (Fig. 1) were soaked in water for one day, followed by cooking under the Kraft pulping process, conducted in a stainless-steel vessel with a 3 L capacity, equipped with a rotating and heating oil bath. The pulping conditions were: 6% active alkalinity charge relative to the dry weight of the raw material, 20% sulfidity, cooking temperature of 140 °C, cooking time of 120 min, and a liquid ratio (liquid to CLs ratio) of 12:1. The solid residue was defibrated and washed with hot water (70 °C) until reaching a neutral (pH = 7). The resultant pulp was screened on a valley flat screen with 0.25 mm slots. Samples of CLs were pulped in triplicate. The bleaching was carried out the traditional way, using sodium hypochlorite with 8% active chlorine for 3 h at 35 °C and pH 10. The bleaching process was carried out in compliance with safety controls and industrial safety requirements. After the bleaching process was completed, the samples were washed thoroughly with running water, given an antichlor treatment of 0.5% sodium sulfite for 30 min, and washed with distilled water. The samples were air-dried and weighed accurately to obtain the percentage of total pulp yield from CLs and then screened using valley type laboratory equipment (Iron Work Corp, Appleton, WI) with a slot size of 0.25 mm. Subsequently, the pulp was beaten to 40°SR with type VOIT valley laboratory equipment (Voit Inc., Appleton, WI).

Fig. 1
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Kraft pulping process of Cotton linters (a), bleached pulp (b,c)

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The yield, kappa number, freeness (Schopper Riegler, SR0), and brightness of the pulp were determined according to TAPPI standard methods T 210 cm-93 [56], T 236 om-13 [57], ISO 5267–1, and T 452 om-92 [58], respectively. The physical strength properties of cotton linter paper pulp (CLP), tensile index, internal tearing index, and burst index were measured according to TAPPI T 220 sp-16 [59], TAPPI T 404 wd-03 [60], TAPPI T 414 om-12 [61], and TAPPI T403 om-15 [62], respectively.

2.2 Source of parchment and textile fibers

Goat parchment was provided by Leather City in Al-Rubiki, Cairo, Egypt, while the Textile fibers were obtained from Golden Tex Company at AL-Asher Men Ramadan City, Cairo, Egypt (Fig. 2). For sterilization of the materials, CLPs and linen textile samples were autoclaved at 121 °C for 20 min, but parchment samples were exposed to a UV lamp at a wavelength of 256 nm for 1.5 h.

Fig. 2
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Samples of Cotton linters Paper (a), Linen Textile (b) and Parchment (c)

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2.3 Essential oils extraction

The essential oils (EOs) from Pinus rigida wood and Origanum majorana green leaves were extracted via the hydrodistillation method, in which ~ 150 g of small pieces of each material were put in a 2 L flask containing 1500 mL of distilled water then connected to a Clevenger unit and heated for 3 h under refluxing [63]. The EOs were collected and dried over anhydrous sodium sulfate; the EO amount was calculated based on sample weight as 0.66 mL/100 fresh leaves of O. majorana and 0.44 mL/100 g of wood from P. rigida. The obtained EOs were kept dry in sealed Eppendorf tubes and stored at 4 °C in the refrigerator until subsequent analysis.

2.4 Chemical analysis of the essential oils

EOs from P. rigida wood and O. majorana green leaves were analyzed for their chemical constituents with a Trace GC Ultra-ISQ mass spectrometer (Thermo Scientific, Austin, TX) with a direct capillary column TG–5MS (30 m × 0.5 mm × 0.25 μm film thickness) apparatus. The column oven temperatures and chemical separation and identification conditions can be found in the previous study [64]. Xcalibur 3.0 data system in the GC–MS with its threshold values was used to confirm that all the mass spectra of the identified compounds were attached to the library. Furthermore, the measurement indices of Standard Index (SI) and Reverse Standard Index (RSI) with values ≥ 650 were used to confirm the identified compounds [44, 63, 65, 66].

2.5 Antifungal activity

2.5.1 Vapor treatment with the essential oils

The extracted EOs were prepared at the concentrations of 500, 250, and 125 μL/L. The respective amount of EO was diluted in 10% DMSO, and 0.5 mL of Tween 40 was added. Tween 40 was added to increase the spread of the EO, which supports the homogeneity of evaporation. Samples of CLPs, linen textile, and parchment, with the dimensions of 2 × 2 cm, were vapor treated with the prepared concentrations of the EOs using the evaporation method [42, 66,67,68]. Briefly, the tested samples were placed in Petri dishes containing 8 layers of filter papers (Whatman No. 1) overlaid by a mesh (polyethylene spacer). The Petri dishes were autoclaved and left to cool. Then, the EOs with respective concentrations were impregnated over the filter papers and kept for 48 h to allow the evaporation of the EOs, which the fumigants (EOs) subsequently absorbed by the tested samples (CLP, linen textile, and parchment).

2.5.2 Inhibition growth of fungi by the essential oils

The three fungi, Aspergillus terreus Ate456, Aspergillus flavus AFl375, and Aspergillus niger Ani245, listed in GenBank under accession numbers MH355953, MH355958, and MH355955, respectively [3, 69], were used in the bioassay. Tests of inhibition of microorganisms were performed in 9 cm Petri dishes with PDA with or without EOs. For comparisons, samples treated with 10% DMSO with Tween40 were used as controls. Each treatment was evaluated in triplicate. A seven-day-old colony from each fungus with a 9 mm diameter was placed in the center of the treated PDA dishes, and the controls were then incubated at 26 ± 1 °C for 14 days. When the mycelial growth filled the Petri dish in the control treatment (negative), the fungal growth inhibition (FGI) percentage was calculated as follows:

$$\mathrm{FGI\%}=\left[\left({\mathrm{A}}_{\mathrm{C}}-{\mathrm{A}}_{\mathrm{T}}\right)/{\mathrm{A}}_{\mathrm{C}}\right]\times 100$$

where AC and AT represent the average diameters of the fungal growth of control and treatment, respectively.

2.6 SEM examination

At the end of the incubation period of CLP, the symptoms or inhibition of fungal infestation over the linen textiles and parchment samples treated with the tested EOs and inoculated with the three fungi were examined using a scanning electron microscope (SEM). The samples were finely coated with gold and examined via SEM-JEOL (JFC-1100E Ion sputtering device, model JSM- 5300, JEOL Co., Tokyo, Japan) at 8 kV.

2.7 Statistical analysis

The fungal growth inhibition was statistically analyzed for two factors (EO type and EO concentration) applied to each material using analysis of variance and the Statistical Analysis Software (SAS, Release 8.02, Cary, NC, USA) system [70]. Differences among means were measured using Duncan’s multiple range test at a 0.05 level of probability.

3 Results and discussion

3.1 Chemical analysis of cotton linters and the pulp paper properties

The summative chemical analysis of Egyptian cotton linters (CLs) is shown in Table 1, where the holocellulose was 88%, or specifically, the α-cellulose was 82%. Previous research showed that the CLP possessed a higher α-cellulose content (98.79%) and lower ash content (0.22%) [71]. The cellulose content dry weight of CLs typically reaches 80% [72, 73]. Another study showed that the fibers of CL contain α-cellulose over 99% and a small amount of residual waxes and oils [74].

Table 1 Chemical composition of Egyptian cotton linters
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Pulp yield, Kappa number, and brightness values of 85%, 3.5, and 75%, respectively, were found for the bleached cotton linter pulp (CLP). Bleached pulp hand sheets made from CLs with a Grammage value of 60 g/m2 showed the following mechanical properties: tear index 11.76 mN·m2/g, burst index 4.2 kPa·m2/g, and tensile index 51 Nm/g. These values were higher than those reported from paper sheets made from some hardwoods pulps such as E. camaldulensis [2, 75, 76]. Other studies showed that papers made from CLP are characterized by a higher curl value of fiber, mostly due to their softness [77].

3.2 Chemical composition of the essential oils and their antifungal activities

The chemical compounds of the essential oil (EO) from Pinus rigida wood are shown in Table 2 and Fig. 3a. The abundant bioactive compounds were 2-methylisoborneol (29.52%), 4-isopropyl-5-methylhex-2-yne-1,4-diol (16.53%), 1,2-cis-1,5-trans-2,5-dihydroxy-4-methyl-1-(1-hydroxy-1-isopropyl)cyclohex-3-ene (12.06%), 2-methyl-2-bornanol (11.86%), (E)-3,4,4-trimethyl-5-oxo-2-hexenoic acid (5.93%), 2,5-dimethyl-3-hexyne-2,5-diol (4.10%), 1-vinyl cyclohexanol (2.87%) and terpinen-4-ol (2.82%).

Table 2 Phytochemicals of essential oil from Pinus rigida analyzed via GC–MS
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Fig. 3
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GC–MS chromatograms of the essential oils analysis from Pinus rigida wood (a) and Origanum majorana green leaves (b)

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The chemical compounds of Origanum majorana green leaf EO are shown in Table 3 and Fig. 3b. The main chemical compounds were cis-β-terpineol (15.4%), terpinen-4-ol (14.39%), oleic acid (10.75%), D-limonene (8.49%), thujanol (7.1%), α-terpineol (6.41%), linalyl anthranilate (5.49%), γ-terpinene (5.06%), sabinene (4.5%), cis-sabinene hydrate acetate (4%), o-cymene (3.9%), and linalool (2.51%).

Table 3 Phytochemicals of the essential oil from Origanum majorana green leaves analyzed via GC–MS
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Samples of cotton linter pulp paper (CLP), linen textile, and parchment treated with P. rigida and O. majorana EOs using the vapor method at 125, 250, and 500 μL/L and compared with the control are shown in Fig. 4a,b,c. Generally, with an increase in the concentration of the tested EOs applied to the tested materials, the fungal radial growth decreased compared to the control samples (10% DMSO).

Fig. 4
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Visual observation of antifungal activity of essential oils applied to cotton linters paper, linen textile and parchment by vapor method at 500, 250 and 125 μL/L. (P): cotton linters paper, (L): linen textile and (T): parchment; against (a) A. terreus; (b) A. flavus; (c) A. niger

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CLP treated with O. majorana EO showed the fungal growth inhibition (FGI) percentages of 47.6% and 46.3%, at 500 μL/L and 250 μL/L, respectively, followed by P. rigida EO (500 μL/L) with FGI of 46% against A. niger growth (Table 4). The treated CLP with P. rigida EO at 500 μL/L showed an FGI of 74%, followed by O. majorana EO with an FGI of 48.6% at the same concentration against the growth of A. flavus. P. rigida and O. majorana EOs at 500 μL/L showed FGI values of 100% and 94.6%, respectively, against the growth of A. terreus.

Table 4 Antifungal activity of treated cotton linter pulp paper with O. majorana and P. rigida EOs
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Table 5 shows the antifungal activity of the tested EOs when applied to parchment samples. At 500 μL/L, O. majorana and P. rigida EOs observed 49% and 46% of FGI, respectively. O. majorana EO at 250 μL/L observed FGI values of 46.6% against the growth of A. niger. The higher activity (FGI 78%) against the growth of A. flavus was observed in parchment samples treated with P. rigida EO at 500 μL/L followed by O. majorana EO (FGI 54.3%). Potent activity against the growth of A. terreus was reported as parchment samples treated with P. rigida EO (500 μL/L), O. majorana EO (500 μL/L), and O. majorana EO (250 μL/L) with FGI values of 100%, 97.3%, and 94.6%, respectively.

Table 5 Antifungal activity of treated parchment with the EOs from O. majorana and P. rigida
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Table 6 presents the antifungal activity of treated linen textiles with the EOs. Linen textiles vapored with O. majorana and P. rigida EOs at 500 μL/L had higher activity against the growth of A. niger with an FGI of 49 and 47%, respectively. The P. rigida EOs at 500 μL/L showed higher activity against A. flavus with an FGI of 77.3%, followed by O. majorana EO with an FGI of 53.3%. Potent antifungal activity against A. terreus was found in linen textile vapored with P. rigida EO at 500 μL/L (FGI of 100%), followed by O. majorana EO at 500 and 250 μL/L with FGI of 97.3 and 96%, respectively.

Table 6 Antifungal activity of treated linen textile with O. majorana and Pinus rigida EOs
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CLP, linen textile, and parchment samples treated with the two EOs showed promising bioactivity against the mold infestation of Aspergillus terreus, A. flavus, and A. niger. These bioactivities could be related to the presence of bioactive compounds in the EOs.

The previous work showed that α-terpineol, borneol, and fenchyl alcohol were the most abundant compounds in P. rigida wood oil [42]. Ethyl ether extract of P. rigida wood identified terpinen-4-ol, cis-4-thujanol, α-terpineol, γ-terpinene, sabinene, fenchol, 14-β-H-pregna, and α-terpinene as the main compounds [78]. Meanwhile, α-terpineol, terpin hydrate, borneol, D-fenchyl alcohol glycol, and limonene were found in the methanol extract from P. rigida wood [41]. The extract from P. rigida wood applied to wood samples showed no changes to their structure and gave some protection against the fungal infestations of Trichoderma harzianum and A. niger [78]. The most abundant chemicals generated from P. rigida wood at the standard emission rate (temperature of 30 °C) were α-pinene, β-pinene, myrcene, and α-terpinene [79]. Caryophyllene, thunbergol, 3-carene, cembrene, α-thujene, and terpinolene were found in the EO from P. roxburghii wood with some bioactivity against bacterial growth [80].

O. majorana EO showed the presence of cis-β-terpineol, terpinen-4-ol, oleic acid, D-limonene, thujanol, α-terpineol, sabinene, linalyl anthranilate, γ-terpinene, and cis-sabinene hydrate acetate as the main abundant compounds. The main component of marjoram EO was terpinen-4-ol [81,82,83,84]. Terpinen-4-ol (30.4%) with cis-sabinene hydrate, α-terpinene, γ-terpinene, α-terpineol, and sabinene were identified as major compounds in marjoram EO [85] with antimicrobial activity. Other compounds such as linalool (32.68%) and terpinen-4-ol (32.30%) were found in the EO of O. majorana, with promising activity against some strains of yeasts, molds, and bacteria [86]. The EO showed a broad range of fungitoxicity against A. niger, A. fumigatus, A. luchuensis, P. chrysogenum, Penicillium italicum, Cladosporium cladosporioides, Fusarium poae, and Alternaria alternata [83].

Terpineol, terpinen-4-ol, 4-thujanol, α-terpineol, cymene, and sabinene were the main EO compounds from O. majorana with effectivity against some fungi (Fusarium verticillioides, F. graminearum, Bipolaris oryzae, and Curvularia lunata) [87]. O. majorana EOs, with their main compounds, terpenen-4-ol, and p-cymene, inhibited mycelia growth of A. alternate [88]. O. majorana EO applied to some wood species had good bio-fungicides against T. harzianum and A. niger without changing their structures [78]. The main compounds in O. majorana EO were 4-carvomenthenol, γ-terpinene, α-terpinene, trans-sabinene hydrate, p-cymene, β-fenchol, limonene, β-caryophyllene, sabinene, myrcene, cis-4-thujanol, terpinolene, α-pinene, linalyl acetate, and γ-elemene [78].

3.3 Scanning electron microscopy observation

3.3.1 SEM images of CLP samples inoculated by molds

The SEM images of the treated CLP samples with the EOs and inoculated with A. terreus are shown in Fig. 5. Extensive mycelial growth of A. terreus over the untreated CLP samples was observed (Fig. 5a). The fungal growth decreased as the CLP was treated with O. majorana EO at 125 μL/L (Fig. 5b). The structure of CLP fibers was clearly shown, and the fungal growth was suppressed when treated with P. rigida EO at 250 μL/L (Fig. 5c) and P. rigida EO at 125 μL/L (Fig. 5d).

Fig. 5
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SEM images of cotton linters paper samples: (a-d) inoculated with A. terreus: (a) without treatment, (b) with O. majorana EO 125 μL/L, (c) with P. rigida EO 250 μL/L, and (d) with P. rigida 125 μL/L. (e–h) inoculated with A. flavus: (e) without treatment, (f) with 125 μL/L O. majorana EO, (g) with 125μL/L P. rigida EO, and (h) with 250 μL/L P. rigida EO. (i-o) inoculated with A. niger: (i) without treatment, (j) with 125 μL/L P. rigida EO, (k) with 250 μL/L P. rigida EO, (l) with 500 μL/L P. rigida EO, (m) with 125 μL/L O. majorana EO, (n) with 250 μL/L O. majorana EO and (o) with 500 μL/L O. majorana EO. Arrows refer to growth of fungal mycelia based on concentrations of oil treatments

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Excessive growth of A. flavus was observed in untreated CLP samples (Fig. 5e), where conidiophores are often seen under SEM examination. Even in the CLP treated with either 125 μL/L of O. majorana EO (Fig. 5f), 125 μL/L of P. rigida EO (Fig. 5g), or 250 μL/L of P. rigida EO (Fig. 5h), fungal growth was still observed.

SEM images of CLP samples inoculated with A. niger showed extensive fungal mycelial growth over the control samples (Fig. 5i) and the vapored samples with 125 and 250 μL/L of P. rigida EO (Fig. 5j,k). Growth of A. niger decreased as CLP was treated with 500 μL/L of P. rigida EO (Fig. 5l), 125 μL/L of O. majorana EO (Fig. 5m), and 250 μL/L of O. majorana (Fig. 5n). The growth of A. niger was vapored with 500 μL/L O. majorana EO (Fig. 5o).

3.3.2 SEM images of parchment samples inoculated with molds

Figure 6 shows SEM images of the inoculated parchment samples with the three molds. The growth of A. terreus is clearly shown over the control samples (Fig. 6a). Insignificant decreases in the fungal growth were observed as parchment vapored with P. rigida EO at 125 μL/L (Fig. 6b) and O. majorana EO at 125 μL/L (Fig. 6c).

Fig. 6
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SEM images of Parchment samples: (a-c) inoculated with A. terreus: (a) without treatment, (b) with 125 μL/L P. rigida EO, and (c) with 125 μL/L O. majorana EO. (d-f) inoculated with A. flavus: (d) without treatment, (e) with 125 μL/L P. rigida EO, and (f) with 125 μL/L O. majorana EO. (g-i) inoculated with A. niger: (g) without treatment, (h) with 125 μL/L P. rigida EO, and (i) with 125 μL/L O. majorana EO. Arrows refer to growth of fungal mycelia based on concentrations of oil treatments

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The same trend of A. flavus fungal growth was observed in untreated parchment samples (control) (Fig. 6d), and the vapor was treated with 125 μL/L of P. rigida EO (Fig. 6e) and with 125 μL/L of O. majorana EO (Fig. 6f). A. niger mycelial growth was shown with extensive distribution over untreated parchment samples (Fig. 6g) and the vapored samples with 125 μL/L of P. rigida EO (Fig. 6h) or 125 μL/L of O. majorana EO (Fig. 6i).

3.3.3 SEM images of linen textile samples inoculated with molds

Figure 7 shows the SEM images of linen textile vapored with the EOs and inoculated with the three molds. The growth of A. terreus is shown in the control samples (Fig. 7a), and this growth was significantly decreased as the linen textile was vapored with P. rigida EO at 125 μL/L (Fig. 7b) and with 125 μL/L of O. majorana EO (Fig. 7c).

Fig. 7
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SEM images of Linen textile samples: (a-c) inoculated with A. terreus: (a) without treatment, (b) with 125 μL/L P. rigida EO, and (c) with 125μL/L O. majorana EO. (d-g) inoculated with A. flavus: (d) without treatment, (e) with 125 μL/L O. majorana EO, (f) with 125 μL/L P. rigida EO, and (g) with 250 μL/L P. rigida EO. (h–l) inoculated with A. niger: (h) without treatment, (i) with 125 μL/L O. majorana EO, (j) with 125 μL/L P. rigida EO, (k) with 250 μL/L P. rigida EO, and (l) with 250 μL/L O. majorana EO. Arrows refer to growth of fungal mycelia based on concentrations of oil treatments

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The extensive growth of A. flavus conidia was observed over the control samples of the linen textile (Fig. 7d). The growth decreased as the samples were vapored with 125 μL/L of O. majorana EO (Fig. 7e) or 125 μL/L of P. rigida EO (Fig. 7f), but the conidia are still shown. With the increased concentration level of P. rigida EO to 250 μL/L, the fungal growth decreased, and the mycelia and conidia were destroyed (Fig. 7g).

Conidia of A. niger were observed over the untreated or control linen textile (Fig. 7h) and decreased as the linen textile was treated with 125 μL/L of O. majorana EO (Fig. 7i), with 125 μL/L of P. rigida EO (Fig. 7j) and 250 μL/L of P. rigida EO (Fig. 7k). The anatomical features of fibers were observed, and the fungal growth was suppressed as the linen textile was vapored with 250 μL/L of O. majorana EO (Fig. 7l).

From the previous SEM results of the studied materials, the mode of action of the studied EOs in A. terreus, A. flavus, and A. niger was measured by SEM. The EO treatments led to the distortion and thinning of the hyphal wall, the absence of conidiophores, and a reduction in hyphal diameter [89]. The damage and decay in both fibers and dyes caused by fungi resulted in a reduction in the hardness of fibers; loss of parts; weakness in fibers and dye; and the separation of parts, stain, and dust [90].

Pulp additives were used to improve the quality of the produced paper sheets, i.e., a significant decrease in A. niger mycelial growth over Papyrus strips treated with S. babylonica leaf extract (2%) or E. camaldulensis bark extract (2%) was observed [44]. For the protection from and prevention of the growth of microorganisms such as fungi and bacteria, pulp papers were treated with extracts and EOs from ornamental and woody plants [3, 4, 45, 46, 69, 91]. No fungal growth of A. terreus and A. flavus was observed in pulp paper treated with oils at levels of 3% and 5% from S. alba seeds, M. azedarach fruits, and M. grandiflora leaves, probably related to the presence of bioactive compounds [31]. The growths of A. niger, Penicillium roqueforti, and Eurotium chevalieri were inhibited at the concentration of 1000 mg/mL of Lemna gibba extract when impregnated with interleaving papers [92].

The obtained results show that the application of EOs to some industrial materials can prevent or stop the spread of mold growths that may be caused during their handling or service. We suggest reusing these oils after a certain period of time, the length of which should be determined in future studies.

4 Conclusions

P. rigida and O. majorana essential oils were used for controlling the growth of Aspergillus terreus, A. flavus, and A. niger, with beneficial effects on organic materials. When applied to industrial materials (cotton linter pulp paper, linen textile, and parchment), the two essential oils possessed promising antifungal properties against A. terreus, A. flavus, and A. niger. These two essential oils could be used to control fungal infestations in various organic materials.