In this study, investigations were carried out to assess the efficiency of two plant essential oils; rosemary and oregano as natural food preservatives. The effect of the plant essential oils at concentrations of 0.1%, 0.5% and 1% was studied in the soft cheese against Salmonella enteritidis and Escherichia coli at fridge temprature over a 14-day period. The essential oils performed well in the inhibition of S. enteritidis and E. coli. It is concluded that selected plant essential oils can act as potent inhibitors of both microorganisms in a food product. At the same time, evaluation of their safety as food preservatives was undertaken via monitoring the genotoxic activity of the mentioned essential oils using Vicia faba test. Vicia faba roots were treated with the above concentrations for 3 hours. Results revealed cytotoxic and genotoxic effects of the applied doses. Mitotic index decreased significantly when compared to control. Chromosomal abnormalities and micronuclei were also observed and the effects were dose-dependent. Despite the efficient role of the studied oils as antimicrobial agents, their genotoxicity potential in eukaryotic cells made them unacceptable as food preservatives, particularly at high doses. Therefore, more research in the use of essential oils as food preservatives is needed.

Fungi are attractive as reducing and stabilizing agents in the biogenic synthesis of silver nanoparticles due to the production of considerable amounts of proteins, high yields, simplicity of handling, and low toxicity of the residues. Nanotechnology is one of the prospective technologies that could be utilized to address the recent issues as agrichemical production lines, nanotechnology production lines can also have drawbacks. As a result, a brand-new branch of nanotechnology called as "green nanotechnology" was developed, integrating biological ideas with physical and chemical procedures to produce nanosized particles with specific uses that are ecologically friendly. Biochemical synthesis methods utilizing microorganisms and plants are being investigated and developed in an effort to create nanoparticles (NPs) in a sustainable and eco-friendly manner. Biological synthesis has grown in favor as a possible alternative to the drawbacks related to physical and chemical methods of synthesis. The current analysis discusses the potential for enhancing plant health and disease resistance using AgNPs produced by endophytic fungi, which will contribute to a greater level of agricultural sustainability. Future research should focus on understanding this important method, it is advised.

Technological application of essential oils, as natural antimicrobial agents, to reduce the effect of pathogenic microorganisms, requires new methods of detection. The present work evaluated the parameters of antimicrobial activity of the essential oils of rosemary (Rosmarinus officinalis) on two pathogenic strains Escherichia coli and Staphylococcus aureus. The MBC and MIC values were of 2.5, 25 μl ml -1 , and values of 1.25 and 5 μl ml -1 for the two strains respectively. In this study, an attempt has been made to evaluate randomly amplified polymorphic DNA (RAPD) analysis for its potential to establish antimicrobial effect of rosemary essential oil. For the preliminary assessment, this study compared the effects occurring at molecular levels in E. coli and Staph. aureus exposed to rosemary essential oil at the MIC concentrations for the two organisms. The qualitative modifications arising in random amplified polymorphic DNA (RAPD) profiles as a measure of DNA effects were compared with control which showed many differences. In conclusion, the measurement of parameters at molecular levels is valuable for investigating the specific effects of agents interacting with DNA.

Solar salterns are an ideal model for extreme environments since they contain a halophilic microorganisms that must adapt to these conditions. In North Sinai, these environments have not gotten much attention. However, the focus of our investigation was on the salterns' waters and saline soil. The study of this microflora showed that it had a lot of different shapes, functions, and ways of using energy. The molecular analysis provided us with a phylogenetic relationship that included Aspergillus isolates as well as archaeal isolates from the genera Haloarcula, Haloferex, and Halobacterium, and also bacteria related to Halomonas and Brevibacillus. The majority of isolates expressed hydrolytic enzymes at high salt concentrations. Finally, the North Sinai Solar Saltern is rich in halophilic populations that produce industrial hydrolytic enzymes.

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