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Main agent orange-red coloured pigment of henna is a molecule called Lawson which is responsible for anti-microbial, anti-tumor, anti-inflammatory and analgesic activity. Chitosan is a biopolymer with high strength, biocom-patibility and biodegradability, non-toxicity and antimicrobial properties. Electrospinning is a method of producing su-bmicron polymeric fibers with high porosity and high surface/volume ratio. In this study, electrospinning of chitos-an/polyethylene oxide (Chit/PEO) nanofibers with the addition of henna extract to create nanofibers with antimicrobial properties were examined. Nanofibers was constructed by electrospinning of polymeric solution with proper size and si-ze distribution of Chit/PEO with a ratio 90/10. Then, Lawsonia inermis (henna) extract as an additive to Chit/PEO co-polymer was added and electrospined on the surface. After characterization of nanofibers using SEM, the antimicrobial properties of polymeric solution and nanofibers were investigated. The scanning electron micrographs showed that Ch-it/PEO nanofibres with a low percentage of henna extract have suitable diameters and size distribution similar to Ch-it/PEO nanofibres without adding extract. In bacteriological studies, it was found that chitosan polymer solutions cont-aining 1% of henna extract has bactericidal properties against Staphylococcus aureus, Escherichia coli and Pseudo-monas aeruginosa bacteries better than polymer chitosan solution without adding the extract.

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Phenazine 1-corboxylic acid (PCA) is an antibiotic, which inhibits the growth of a vast number of micro-organisms. PCA has has been applied in fields such as pharmaceutical, agricultural, marine and chemical industries. In this study, the antibiotic properties of PCA (produced by pseudomonas aeruginosa MUT.3, which is kept at the Microbial Collection of Malek Ashtar University of Technology) was studied. The impacts of temperature and light conditions on the activity of PCA was investigated within a 230-day period. To investigate the rate of PCA destruction in the experiment, high performance liquid chromatography (HPLC) was utilized. Moreover, the antibacterial activity of PCA under various conditions was studied by minimum inhibitory (MIC) and minimum biocidal concentration (MBC) methods against E. coli DH5α. The results showed that PCA could be active up to 210 days in darkness (at 25^oC). Meanwhile, the antibacterial activity of PCA was reduced to 100 and 50 days by increasing the temperature to 35 and 45^oC, respectively. In addition, PCA could be active up to 120 and 10 days in visible and ultraviolet light condition, respectively. The MIC and MBC data were consistent with the HPLC results. Detailed data on the activity and stability of phenazine 1-corboxylic acid under various environmental conditions, as presented in this study, could be helpful in industries and healthcare services.
 
 

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Exopolymers (EPS) are high-molecular-weight polymers secreted by some micro-organisms and have several applications in food, pharmaceutical, packaging and agricultural industries, as well as medicine. Actinobacteria are valuable bacteria in biotechnology and many commercial drugs such as antibiotics, antioxidants and immune-suppressant agents are derived from Actinobacteria. Recently, their other capabilities such as exopolymer production have been taken into consideration. Due to the high potential of actinobacteria in producing various compounds and increased prevalence of infections by antibiotic-resistant pathogens, the aim of the present study was to evaluate the potential of isolated Actinobacteria from various locations of Iran to produce EPS with antimicrobial activity. Appropriate dilutions of the samples were, therefore, cultured in ISP2 medium after treatment. The isolates were primarily identified by morphological tests. Then, their ability to produce EPS was investigated in BHI medium with 5% sucrose. The exopolymers of the most efficient strain were analyzed by UV-visible spectroscopy and FT-IR. Finally, the most efficient isolate was molecularly identified. Of the 120 isolates, 38 were able to produce EPS, and six had significant capability of producing EPS (10-14 g/L) and showed antibiotic activity against Staphylococcus aureus, Bacillus subtilis and Aspergillus niger. The EPS of the strain So49 had high absorbance in 190-230 nm, but did not have absorbance in 260-280 nm. Therefore, it does not have any protein impurity. The EPS has hydroxyl and carboxyl functional groups, according to FT-IR analysis. 16S rRNA gene analysis showed that the most efficient isolate had 99.68% similarity to Promicromonospora xylanilytica. 


 

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The biosynthesis of nanoparticles (NPs) has been proposed due to its fast, clean, safe, and cost-effective production and being efficient alternative to conventional physicochemical methods. This study aimed to isolate and identify aquatic yeast strains for their potential to form Zinc oxide nanoparticles (ZnONPs). A yeast strain, NS02, with high tolerance against zinc ion (5.25 mM) was isolated using the enrichment technique and was selected as efficient candidate for the biosynthesis of ZnONPs under cell-free extract (CFE) strategy. The preliminary evaluation on the formation of ZnONPs was performed by visual observation and UV-visible absorption spectra of the biosynthesized ZnONPs. The morphology, size and elemental distribution of the nanoparticles were determined by Field emission scanning electron microscopy (FESEM) equipped with energy-dispersive X-ray (EDX). X-ray diffractometer (XRD) was used to identify the crystalline phase of the ZnONPs. Antibacterial activity of ZnONPs against pathogenic bacteria isolated from the clinical specimens was investigated using agar well diffusion method. The isolate NS02 was characterized based on their morphological properties and amplification the ITS-5.8S-ITS2 rDNA regions. The present study pioneered the capabilities of the native aquatic strain Rhodotorula pacifica for the extracellular synthesis of ZnONPs with CFE strategy. The biosynthesized ZnONPs had a growth inhibitory effect all tested clinical isolates due to their nanometric size and well-defined dispersity. This investigation is attempted to indicate the novel microbial sources of aquatic yeasts as biological plant in the synthesis of ZnONPs with antimicrobial activity under cell-free extract strategy.
 

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The aim of the present work was to produce a stable nanoemulsion containing clove (Syzygium aromaticum) essential oil (PCLO) and evaluate its antimicrobial activity. The effect of the preparation technique, the type of surfactant and the ratio of surfactant to oil was evaluated to optimize the preparation formula of oil-in-water nanoemulsion. The optimized formula prepared by low energy production method containing 4% w/w PCLO and 12% w/w mixed surfactant (SDS + Tween 80) produced a clear and stable nanoemulsion for 90 days with an average particle diameter below 150 nm. The antibacterial activity of pure PCLO and its nanoemulsions (NCLO) was investigated by disk diffusion, agar well, and broth methods in 3 indicator bacteria of gastrointestinal infections, Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium. Minimum inhibitory concentration (MIC) and bacteriocidal concentration (MBC) as well as dynamic killing time were determined in the tested bacteria. Strong antibacterial activity of PCLO and NCLO was revealed in the concentration range of 1000-2000 ppm. The killing kinetics study showed that during the first 15 minutes of exposure to NCLO at the MIC concentration, there was a rapid and extensive reduction in the amount of viable microorganisms. The presented data, considering the optimal performance of antimicrobial substances in food, cosmetics and chemical industries, can help in the rational design of nanoemulsion-based essential oil delivery systems.
 

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Calyx of eggplant is recognized as agricultural byproducts containing significant levels of phenolic, flavonoid, and anthocyanin compounds that facilitate the reduction of silver ions, enabling the eco-friendly production of silver oxide nanoparticles through a green synthesis approach. The utilization of silver oxide nanoparticles has garnered considerable interest in various industries due to their versatile applications and environmentally sustainable nature. Various analytical techniques such as ultraviolet- visible spectrophotometry, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and dynamic light scattering were employed to confirm the formation of silver oxide nanoparticles and characterize their properties. The antioxidant, antibacterial, and antifungal activities of the silver oxide nanoparticles and the aqueous extract of calyx of eggplant were evaluated through assays including 1,1-diphenyl-2-picrylhydrazyl radical scavenging, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical inhibition, disc diffusion, minimum inhibitory concentration and minimum bactericidal concentration. The absorption peak at 422 nm confirmed the presence of silver oxide nanoparticles, with a particle size of approximately 140 nm determined by DLS analysis and a spherical shape observed through SEM imaging. The biological activities of the silver oxide nanoparticles, including their antioxidant properties and antimicrobial effects were found to be superior to those of the aqueous calyx of eggplant extract.