Biosynthesis Of Gold Nanoparticles Research Articles

Gold Nanoparticles Biosynthesis Through Green Synthesis Mediated by Leaf Extract from Diospyros Kaki L. (Persimmon) Using the Microwave Extraction Method

Gold Nanoparticles Biosynthesis Through Green Synthesis Mediated by Leaf Extract from Diospyros Kaki L. (Persimmon) Using the Microwave Extraction Method

Antibacterial properties of synthesized Melaleuca cajuputi-leaf gold nanoparticles

Biosynthesized gold nanoparticles (AuNPs) were successfully synthesized by using Melaleuca cajuputi leaf extract, and their prospective antibacterial efficacy was assessed against Vibrio parahaemolyticus. TEM analysis revealed biosynthesized M. cajuputi gold nanoparticles (MC-AuNPs) were spherical in shape with a surface plasmon resonance (SPR) band observed at 535 nm and particle sizes ranging from 10–50 nm. The MC-AuNPs showed good antibacterial properties against V. parahaemolyticus with MIC and MBC values of 0.0075 g/mL.

Extraction of Synephrine from Waste Peels of Citrus sinensis and Green Synthesis of Gold Nanoparticles from it against Dermatophytes

The main object of the current work was to determine the antifungal efficiency of secondary metabolites product called synephrine that extracted from Citrus sinesis peels and the ability of synephrine to biosynthesis gold nanoparticles from HAucl4 which consider environmentally favourable method, then determine their activity against pathogenic human dermatophyte. The identification of synephrine done by Thin layer chromatography (TLC), High Performance Liquid Chromatography (HPLC) and The Fourier Transform Infrared (FTIR). The characterization of gold nanoparticles by using Ultra Violet-Visible Spectroscopy (UV-Vis), Field – Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared (FTIR), confirmed the biosynthesis of gold nanoparticles in diameter and morphology for AuNps biosynthesis by C. sinensis was 9.7-31 (nm) rounded to oval shape. The synephrine and AuNps that formed use it against some dermatophytes Trichophyton mentographytes, Trichophyton rubrum and Microsporum canis, the activity of synephrine against T. mentographytes at (10, 15 and 20 mg/mL) give less inhibition effect as compare with antifungal effect, while M. canis in 15 mg/mL show best effect than antifungal and for gold nanoparticles most concentration effective was (20 mg/mL).

Biosynthesis of gold nanoparticles mediated by Curcuma longa extract: Evaluation of its catalytic activity for the degradation of environmental pollutants and study of anti-lung adenocarcinoma effects

It is essential to recognize efficient heterogeneous catalysts for environmental remediation that can eliminate organic contaminants or transform them into beneficial byproducts. Herein, we have designed and developed a gold nanoparticle based green nanocomposite material templated over the Curcuma longa extract. The Au NPs/C. longa nanomaterial was thoroughly characterized by FT-IR and UV–Vis spectroscopy followed by FE-SEM, EDX, TEM and XRD analysis. Subsequently, towards the wastewater treatment, it demonstrated excellent potential in the reduction of water contaminant toxic organic dyes like methylene blue (MB), methyl orange (MO), and 4-nitrophenol (4-NP) following excellent kinetics, as monitored by UV–Vis spectrophotometer. The reaction followed a pseudo-first order kinetics. The robustness of the nanocatalyst was justified by reusability studies, and hot filtration test and the catalytic activity did not substantially decline over the course of seven cycles. Towards the assessment of biological activity of Au NPs/C. longa nanocomposite antioxidant capacity was evaluated first using the DPPH radical scavenging method. Further, the study was extended in the investigation of anti-lung cancer properties against a number of standard lung cancer cell lines, viz., NCI-H661, NCI-H1975, NCI-H1573, and NCI-H1563 following MTT colorimetric in vitro studies. Curcuma longa-modified Au NPs are thought to have potential biological activities because of their exceptional capacity to produce reactive oxygen species (ROS).

Biosynthesis of gold nanoparticles mediated by medicinal phytometabolites: An effective tool against Plasmodium falciparum and human breast cancer cells

Gold nanoparticles (AuNPs) were synthesized using leaf extracts obtained from the medicinal plants Abutilon theophrasti Medik., Origanum majorana L., Euphorbia hirta L., and Senna auriculata (L.) Roxb. The in vitro antiplasmodial and anticancer activities of AuNPs were assessed against blood-stage malaria parasites and human breast cancer cells, respectively. AuNPs were examined using UV-VIS spectroscopy, HRTEM, DLS, zeta potential, XRD, and FTIR. All the AuNPs exhibited the surface plasmon resonance (SPR) band around 530 nm, which supports the formation of gold particles. The FTIR indicated possible bioactive molecules as constituents of the AuNPs formed. The fluorescence based SYBR Green I assay was utilized to investigate the anti-plasmodial action of AuNPs on the erythrocytic phases of 3D7 (chloroquine drug-sensitive) and INDO (chloroquine drug-resistant) strains of Plasmodium falciparum. The anti-plasmodial IC50 values of the synthesized A. theophrasti AuNPs (N1), O. majorana AuNPs (N2), E. hirta AuNPs (N3), and S. auriculata AuNPs (N4) were 76, 60, 32, and 20 against Pf3D7, and >100, 48, 72, and 36 μg/mL against PfINDO, respectively. N4 showed the highest activity against both P. falciparum strains and also exhibited a high CC50 (480 μg/mL) against human embryonic kidney (HEK293) cells, which leads to a great selectivity index of 24. The in vitro anticancer potential of AuNPs (N1, N2, N3, and N4) was assessed using MCF-7 cells, and the IC50 values were 8.25, 20.25, 20.40, and 24.49 μg/mL, respectively. The present study demonstrated that AuNPs derived from plant extracts may be useful therapeutic agents for treating human breast cancer and malaria.

Process optimization for gold nanoparticles biosynthesis by Streptomyces albogriseolus using artificial neural network, characterization and antitumor activities

Gold nanoparticles (GNPs) are highly promising in cancer therapy, wound healing, drug delivery, biosensing, and biomedical imaging. Furthermore, GNPs have anti-inflammatory, anti-angiogenic, antioxidants, anti-proliferative and anti-diabetic effects. The present study presents an eco-friendly approach for GNPs biosynthesis using the cell-free supernatant of Streptomyces albogriseolus as a reducing and stabilizing agent. The biosynthesized GNPs have a maximum absorption peak at 540 nm. The TEM images showed that GNPs ranged in size from 5.42 to 13.34 nm and had a spherical shape. GNPs have a negatively charged surface with a Zeta potential of − 24.8 mV. FTIR analysis identified several functional groups including C–H, –OH, C–N, amines and amide groups. The crystalline structure of GNPs was verified by X-ray diffraction and the well-defined and distinct diffraction rings observed by the selected area electron diffraction analysis. To optimize the biosynthesis of GNPs using the cell-free supernatant of S. albogriseolus, 30 experimental runs were conducted using central composite design (CCD). The artificial neural network (ANN) was employed to analyze, validate, and predict GNPs biosynthesis compared to CCD. The maximum experimental yield of GNPs (778.74 μg/mL) was obtained with a cell-free supernatant concentration of 70%, a HAuCl4 concentration of 800 μg/mL, an initial pH of 7, and a 96-h incubation time. The theoretically predicted yields of GNPs by CCD and ANN were 809.89 and 777.32 μg/mL, respectively, which indicates that ANN has stronger prediction potential compared to the CCD. The anticancer activity of GNPs was compared to that of doxorubicin (Dox) in vitro against the HeP-G2 human cancer cell line. The IC50 values of Dox and GNPs-based treatments were 7.26 ± 0.4 and 22.13 ± 1.3 µg/mL, respectively. Interestingly, treatments combining Dox and GNPs together showed an IC50 value of 3.52 ± 0.1 µg/mL, indicating that they targeted cancer cells more efficiently.

Biosynthesis of Gold Nanoparticles Using Aqueous Extract of Paramignya trimera Roots and Its Anticancer Activity

Developing environment-friendly processes for metal nanoparticle synthesis without using toxic chemical is very necessary to meet the demand for biological and medical applications. In this work, biosynthesis of gold nanoparticles (AuNPs) using aqueous extract of Paramignya trimera roots as the reducing and stability agents was carried out. The formation of gold nanoparticles was confirmed by the presence of an absorption peak at 550 nm using UV–Visible spectrophotometry. The size and morphology of gold nanoparticles was monitored by Field emission scanning electron microscopy (FE-SEM) and High resolution transmission electron microscopy (HR-TEM). Analysis of these particles showed the synthesized AuNPs were spherical in shape, with the particle size range of 10 nm–15 nm. The element gold and the crystalline nature of AuNPs were finalized using Energy dispersive X-ray (EDX) and X-ray diffraction (XRD) spectrometer, respectively. Fourier transform infrared (FTIR) spectroscopy revealed possible involvement of reductive groups on the surfaces of nanoparticles. The synthesized AuNPs are evaluated for its activity against MCF-7, HepG2, KB, LU-1 and MKN7 cancer cell lines with inhibition concentration 50% (IC50) of 2.01, 7.60, 3.89, 3.99 and 3.53 ppm respectively after 72 hours of treatment.

Cytotoxicity Assay of Biosynthesized Gold Nanoparticles for Synephrine Extracted from Citrus Sinesins Peels

In this study synephrine extracted from C. sinesins peels. Detected by TLC, HPLC and biosynthesized gold nanoparticles from it, then characterization of synthesize of gold nanoparticles (AuNps) by UV-visible spectroscopy Fourier Transform Infrared (FTIR), which confirm presence of AuNps in diameter size range to (9-31) nm and determined their toxicity assay on lymphoid human cell in 24, 48 and 72 hours. The finding obtained from applying gold nanoparticles at different concentrations for 24, 48, and 72 hours showed that’s the least cytotoxicity value was in 2.351 in 10 mg/ml for Citrus sinensis extract in 24 hours. which gave indicate that synephrine extracted have not toxic effect inhibition rate of this maximum 5.511 in AuNp biosynthesized in 20 mg/ml concentration in 72 hours.

Monstera deliciosa mediated single step biosynthesis of gold nanoparticles by bottom-up approach and its non-antimicrobial properties.

The online version contains supplementary material available at 10.1007/s13205-023-03898-0.

Biosynthesis of Gold Nanoparticles Using Quince Seed Water Extract and Investigation of Their Anticancer Effect Against Cancer Cell Lines.

In this study, gold nanoparticles (Au-NPs) were synthesized using HAuCl4 and quince seed mucilage (QSM) extract, which was characterized by conventional methods including Fourier transforms electron microscopy (FTIR), UV-Visible spectroscopy (UV-Vis), Field emission electron microscopy (FESEM), Transmission electron microscopy (TEM), Dynamic light spectroscopy (DLS), and Zeta-potential. The QSM acted as reductant and stabilizing agents simultaneously. The NP's anticancer activity was also investigated against osteosarcoma cell lines (MG-63), which showed an IC50 of [Formula: see text]/mL.

Biosynthesis of metal nanoparticles: Bioreduction and biomineralization

Abstract The biosynthesis of metal nanoparticles by plants, bacteria, and cells has been receiving considerable attention in recent years. The traditional synthesis of metal nanoparticles always needed high temperatures, high pressure, and toxic agents. However, the biosynthesis process (including bioreduction and biomineralization) is simpler, safe, economical, and green. The process of biosynthesis can insulate toxic agents, streamline flux, increase the transition efficiency of interactants, and improve the product yield. The biosynthesized metal nanoparticles share similar characteristics with traditional ones, serving as photosensors to achieve light-to-heat/energy transduction, or a drug delivery system. The biosynthetic metal nanoparticles thus could be widely applied in the medical field for disease diagnosis and treatment. It contributed a novel modality for the facile and green synthesis of metal nanoparticles. Increasing studies have been exploring the mechanism for the biosynthesis of metal nanoparticles, devoted to a controllable biosynthesis process. Combined with our previous studies on the biosynthesis of gold nanoparticles with green tea, tumor cells, and cell components, we reviewed the green methods of bioreduction and biomineralization of metal nanoparticles including the internal mechanism, aimed to make a comprehensive introduction to the biosynthesis of metal nanoparticles and relevant biomedical applications, and inspired further research.

Impedance nanobiosensor based on enzyme-conjugated biosynthesized gold nanoparticles for the detection of Gram-positive bacteria.

In this report, gold nanoparticles (GNPS) were synthesized using cell-free extracts of seven different isolates, namely, Pseudomonas aerogenosa CEBP2, Pseudomonas sp. CEBP1, Pseudomonas pseudoalcaligenes CEB1G, Acinetobactor baumani CEBS1, Cuprividus sp. CEB3, Micrococcus luteus CUB12, and Pandoraea sp. CUB2S. The spectroscopic (UV-vis, FTIR, DLS, XRD, EDS) and microscopic (FESEM, TEM) results confirm the reduction of Au3+ to Au0 in the presence of biomolecules having reducing as well as self-stabilizing activity. In this green synthesis approach, the average particle size of biosynthesized GNPS might vary (4-60 nm) depending on the bacterial species, pH of the media, incubation time, and temperature. In this study, GSH-modified BSGNPs (Au-GSH) have shown antimicrobial activity with better stability against Gram-positive bacteria. After conjugation of lysozyme with Au-GSH (lyso@Au-GSH), the zone of inhibition was enhanced from 12 to 23 mm (Au-GSH). The TEM study shows the spherical GNP (16.65 ± 2.84) turns into a flower-shaped GNP (22.22 ± 3.12) after conjugation with lysozyme due to the formation of the protein corona. Furthermore, the nanobioconjugate (lyso@Au-GSH) was immobilized with Nafion on a glassy carbon electrode to fabricate a label-free impedance biosensor that is highly sensitive to monitor changes in the transducer surface due to biomolecular interactions. The uniquely designed biosensor could selectively detect Gram-positive bacteria in the linear range of 3.0 × 101-3 × 1010 cfu mL-1 with RE <5%. The proposed simplest biosensor exhibited good reproducibility (RSD = 3.1%) and excellent correlation (R2 = 0.999) with the standard plate count method, making it suitable for monitoring Gram-positive bacterial contamination in biofluids, food, and environmental samples.

The hepato- and neuroprotective effect of gold Casuarina equisetifolia bark nano-extract against Chlorpyrifos-induced toxicity in rats

BackgroundThe bark of Casuarina equisetifolia contains several active phytoconstituents that are suitable for the biosynthesis of gold nanoparticles (Au-NPs). These nanoparticles were subsequently evaluated for their effectiveness in reducing the toxicity induced by Chlorpyrifos (CPF) in rats. ResultsVarious hematological and biochemical measurements were conducted in this study. In addition, markers of oxidative stress and inflammatory reactions quantified in liver and brain tissues were evaluated. Histopathological examinations were performed on both liver and brain tissues. Furthermore, the native electrophoretic protein and isoenzyme patterns were analyzed, and the relative expression levels of apoptotic genes in these tissues were determined. The hematological and biochemical parameters were found to be severely altered in the group injected with CPF. However, the administration of Au-C. equisetifolia nano-extract normalized these levels in all treated groups. The antioxidant system markers showed a significant decrease (P ≤ 0.05) in conjunction with elevated levels of inflammatory and fibrotic markers in both liver and brain tissues of the CPF-injected group. In comparison, the pre-treated group exhibited a reduction in these markers when treated with the nano-extract, as opposed to the CPF-injected group. Additionally, the nano-extract mitigated the severity of histopathological lesions induced by CPF in both liver and brain tissues, with a higher ameliorative effect observed in the pre-treated group. Electrophoretic assays conducted on liver and brain tissues revealed that the nano-extract prevented the qualitative changes induced by CPF in the pre-treated group. Furthermore, the molecular assay demonstrated a significant increase in the relative expression of apoptotic genes in the CPF-injected rats. Although the nano-extract ameliorated the relative expression of these genes compared to the CPF-injected group, it was unable to restore their values to normal levels. ConclusionOur results demonstrated that the nano-extract effectively reduced the toxicity induced by CPF in rats at hematological, biochemical, histopathological, physiological, and molecular levels, in the group pre-treated with the nano-extract.

Enhanced antidiabetic and antioxidant properties of gold nanoparticles green synthesized using blossom extract of Azadirachta indica: In vitro studies

This study describes the in situ biosynthesis of gold nanoparticles (AuNPs) using neem blossom (Azadirachta indica) extract with enhanced in vitro anti-diabetic and antioxidant properties. The formation of AuNPs was confirmed by the characteristic optical response through the surface plasmon resonance (SPR) band observed around 530 nm. The effect of phytochemical in the formation of AuNPs was investigated using Fourier-transform infrared spectroscopy (FTIR). The effect of reaction parameters such as temperature, pH and precursor concentration on the size and surface morphology of AuNPs was optimized using the SPR band. The metallic form of phytosynthesised AuNPs was confirmed by X-ray photoelectron spectra (XPS) results with a distinctive binding energy difference of 4f shells ΔE = 3.8 eV. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) studies confirmed the crystalline nature of the particles formed. The antioxidant property of AuNPs demonstrated the influence of phytochemical surfactants coated on the surface of AuNPs and the results revealed the higher antioxidant (90 %) efficiency compared to standard ascorbic acid. phytosynthesised AuNPs demonstrated 79 % enzyme inhibition efficiency in α-amylase assays. The antimicrobial evaluation results revealed the exceptional microbicidal efficacy of AuNPs against both gram-positive and gram-negative bacteria. Phytochemically activated AuNPs showed improved antioxidant, antimicrobial and antidiabetic properties and it could be a promising candidate for biological applications in medicine.

The anti-inflammation and skin-moisturizing effects of Boehmeria tricuspis-mediated biosynthesized gold nanoparticles in human keratinocytes.

Introduction: Recently, nanotechnology has emerged as a potential technique for skin generation, which has several treatment advantages, such as decreased drug cytotoxicity and enhanced skin penetration. Boehmeria tricuspis (BT) belongs to the Urticaceae family and is rich in phenolic and flavonoid compounds. In this study, we biosynthesized gold nanoparticles (BT-AuNPs) using BT extract to explore their anti-inflammatory and skin-moisturizing properties in keratinocytes. Methods: Field-emission transmission electron microscopy, energydispersive X-ray spectrometry, dynamic light scattering, and Fourier-transforminfrared spectroscopy were used to examine the synthesized BT-AuNPs. qRT-PCR, western blot, and ELISA were applied for investigating the effect of BT-AuNPs on anti-inflammation and moisturizing activity in HaCaT cells. Results: At concentrations below 200 μg/mL, BT-AuNPs had no cytotoxic effect on keratinocytes. BT-AuNPs dramatically alleviated the expression and secretion of inflammatory chemokines/cytokine, such as IL-6, IL-8, TARC, CTACK, and RANTES in keratinocytes stimulated by tumor necrosis factor-α/interferon-γ (T + I). These anti-inflammatory properties of BT-AuNPs were regulated by inhibiting the NF-κB and MAPKs signaling pathways. Furthermore, BT-AuNPs greatly promoted hyaluronic acid (HA) production by enhancing the expression of hyaluronic acid synthase genes (HAS1, HAS2, and HAS3) and suppressing the expression of hyaluronidase genes (HYAL1 and HYAL2) in HaCaT cells. Discussion: These results suggest that BT-AuNPs can be used as a promising therapeutic alternative for treating skin inflammation. Our findings provide a potential platform for the use of BT-AuNPs as candidates for treating inflammatory skin diseases and promoting skin health.

Phytochemical analysis, characterization, and biosynthesis of gold nanoparticles, zinc oxide nanoparticles, and gold-zinc oxide nanocomposites from phoenix dactylifera L. seeds: Biological evaluation

Phytochemical analysis, characterization, and biosynthesis of gold nanoparticles, zinc oxide nanoparticles, and gold-zinc oxide nanocomposites from phoenix dactylifera L. seeds: Biological evaluation

Novel biosynthesis of gold nanoparticles for multifunctional applications: Electrochemical detection of hydrazine and treatment of gastric cancer

In this work, an environmentally friendly strategy was used to synthesize gold nanoparticles (Au NPs) using Olea europaea (olive) fruit. Transmission electron microscopy (TEM), UV–Vis spectroscopy, X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) were used to characterize the physicochemical properties of the synthesized NPs. An Au NPs modified glassy carbon electrode was used to investigate the direct electrochemical oxidation of hydrazine. The suggested hydrazine sensor has good performance, such as a wide linear range (2.5–275 μM), low limit of detection (0.09 μM), notable selectivity and excellent reproducibility (RSD = 2.2%). The in-vitro cytotoxicity of three human cancer cell lines (KATOIII, NCI-N87, and SNU-16) was also explored with various concentrations of Au NPs prepared from olive fruit extract. Bio-synthesized Au NPs were found to have cytotoxic properties against gastric cancer in humans based on MTT assay protocol. The obtained results show that green synthesized Au NPs can be successfully employed in electrochemical sensing and cancer treatment applications.

Biosynthesis of Gold Nanoparticles by Aspergillus Niger And Their Role Against Pathogenic Bacteria

The study included the use of Aspergillus niger filtrate for the biosynthesis of gold nanoparticles (GNPs) using a reducing medium designed for this purpose. The synthesis of Nanoparticles was verified by means of detections by spectrophotometry, X-ray diffraction, FTIR, and scanning electron microscopy. Nanoparticles were used to inhibit pathogenic bacteria obtained from urinary infections patients, and they included Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus by poisoning the nutrient medium and drilling method. It was also verified that there are no toxins accompanying the biosynthesis of these nanoparticles by the ammonia method. The detections of characterization of GNPs confirmed that the particles were synthesized in spherical, oval, and crystalline shapes with sizes ranging from a few nanometers to 500 nanometers, and they gave a light absorption band at the wavelength of 520 nanometers. Concerning the effect of GNPs on pathogenic bacteria, the method of poisoning the media confirmed that the 15% concentration was significantly effective against the three bacterial species, as it gave the lowest diameter of colony growth (1.1, 1.6, 2.3) cm for Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus respectively. As for the drilling method, it also showed a high significant ability of 15% concentration to inhibit the tested bacteria by measuring the inhibition zone, which gave an area of ​​(5.1, 5.4,6) cm for Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus respectively, with regard to the toxicity test, the study showed that the isolate used in the synthesis does not produce toxins, which confirms its suitability and dependence in the biosynthesis of nanoparticles.

Biosynthesized gold nanoparticles that activate Toll-like receptors and elicit localized light-converting hyperthermia for pleiotropic tumor immunoregulation

Manipulating the tumor immune contexture towards a more active state can result in better therapeutic outcomes. Here we describe an easily accessible bacterial biomineralization-generated immunomodulator, which we name Ausome (Au + [exo]some). Ausome comprises a gold nanoparticle core covered by bacterial components; the former affords an inducible hyperthermia effect, while the latter mobilizes diverse immune responses. Multiple pattern recognition receptors actively participate in Ausome-initiated immune responses, which lead to the release of a broad spectrum of pro-inflammatory cytokines and the activation of effector immune cells. Upon laser irradiation, tumor-accumulated Ausome elicits a hyperthermic response, which improves tissue blood perfusion and contributes to enhanced infiltration of immunostimulatory modules, including cytokines and effector lymphocytes. This immune-modulating strategy mediated by Ausome ultimately brings about a comprehensive immune reaction and selectively amplifies the effects of local antitumor immunity, enhancing the efficacy of well-established chemo- or immuno-therapies in preclinical cancer models in female mice.

Biosynthesis of gold nanoparticles using aqueous extract of Ricinus cummunis leaves to augment catalytic degradation of organic dyes and study of its antifungal and antibacterial activities

In this study, biosynthesis of gold nanoparticles (Au NPs) using aqueous extract of fresh leaves of Ricinus cummunis plant is reported without the use of any synthetic chemical in the reaction process. The prepared NPs are mostly spherical in shape with some particles having triangular or hexagonal structures. The average size of the particles as calculated using TEM data is 18 nm. The biosynthesised Au NPs were studied for their application in remediation of Congo Red, Methylene Blue, Reactive Red 120 and Rhodamine B dyes present in industrial effluents. The degradation of dyes was confirmed spectrophotometrically using UV–Vis Spectrophotometer. Reactive Red 120 and Congo red dyes were most effectively reduced with 88% degradation. The Au NPs were further studied for their potential as an effective antifungal agent against fungal strains namely Candida albicans and Aspergillus fumigatus and antibacterial properties against Bacillus subtilis (Gram +ve) and Pseudomonas aeruginosa (Gram −ve) bacterial strains. The MIC values being 7.8 and 15.6 (μg/mL) for Bacillus subtilis and Pseudomonas aeruginosa respectively.