Exploring albumin-sulfonephthalein dyes interactions by a chemometric-assisted and multi-technique equilibria analysis in solution.

Albumin is undoubtedly the most studied protein thanks to its widespread diffusion and biochemistry; despite its binding ability towards different dyes, provoking dye's colour change, has been exploited for decades for quantification purposes, the joint effect of working pH, ionic strength, and dye's pKa still remains only sporadically discussed. In the present study, the interaction of Bovine Serum Albumin (BSA) with five dyes belonging to the sulfonephthalein group, Bromophenol Blue (BPB, pKa = 3.75), Bromocresol Green (BCG, pKa = 4.42), Chlorophenol Red (CPR, pKa = 5.74), Bromocresol Purple (BCP, pKa = 6.05) and Bromothymol Blue (BTB, pKa = 6.72), is investigated at four working pH values (3.5, 6.0, 7.5 and 9.0) and two ionic strength conditions by UV-Vis spectroscopy. Principal Component Analysis is then applied to rationalize dye behavior upon BSA addition at each pH value and to summarize the protein effect on dyes' spectral features, identifying three general behaviors. The most relevant systems are then submitted to further characterization involving a solution equilibria study aimed at determining conditional binding constants for the selected DSA-dye adducts and fluorescence, CD, and 1H NMR spectroscopy to evaluate the binding effect on the species involved.

Convection-Enhanced Drug Delivery: Experimental and Analytical Studies of Infusion Behavior in an In Vitro Brain Surrogate.

Convection-enhanced drug delivery (CED) directly infuses drugs with a large molecular weight toward target cells as a therapeutic strategy for neurodegenerative diseases and brain cancers. Despite the success of many previous in vitro experiments on CED, challenges still remain. In particular, a theoretical predictive model is needed to form a basis for treatment planning, and developing such a model requires well-controlled injection tests that can rigorously capture the convective (advective) and diffusive transport of an infusate. For this purpose, we investigated the advection-diffusion transport of an infusate (bromophenol blue solution) in the brain surrogate (0.2% w/w agarose gel) at different injection rates, ranging from 0.25 to 4 µL/min, by closely monitoring changes in the color intensity, propagation distance, and injection pressures. One dimensional closed-form solution was examined with two variable sets, such as the mathematically calculated coefficient of molecular diffusion and average velocity, and the hydraulic dispersion coefficient and seepage velocity by the least squared method. As a result, the seepage velocity was greater than the average velocity to some extent, particularly for the later infusion times. The poroelastic deformation in the brain surrogate might lead to changes in porosity, and consequently, slight increases in the actual flow velocity as infusion continues. The limitation of efficiency of the single catheter was analyzed by dimensionless analysis. Lastly, this study suggests a simple but robust approach that can properly capture the convective (advective) and diffusive transport of an infusate in an in vitro brain surrogate via well-controlled injection tests.

Green-adapted spectrophotometric determination of fostemsavir based on selective bromophenol blue extraction; reduction of hazardous consumption using computational calculations.

A computationally-assisted and green spectrophotometric method has been developed for the determination of fostemsavir, a recently FDA-approved drug used in combination with antiretroviral drugs to treat multidrug-resistant HIV-1 infection. The method was developed using computational studies and solvent selection based on green chemistry principles. The density functional theory method was employed to identify bromophenol blue as the preferred acid dye for efficient extraction of fostemsavir. The solvent selection process involved a careful evaluation of the green ranking of solvents, which led to the use of water as the solvent. The method involved the extraction of fostemsavir with bromophenol blue to form a yellow ion-pair complex, which exhibited maximally sharp peaks at 418 nm, enabling sensitive visible spectrophotometric determination of fostemsavir in bulk and pharmaceutical preparations. The extraction procedures were optimized, and the method was demonstrated to be sensitive over the concentration range of 2-12 µg/mL fostemsavir. Furthermore, the method was evaluated with respect to green chemistry principles using the analytical eco-scale, the green analytical method index, and analytical greenness metric approach, all of which confirmed that the data obtained by the proposed method were environmentally acceptable.

Use of Euphorbia balsamifera Extract in Precursor Fabrication of Silver Nanoparticles for Efficient Removal of Bromocresol Green and Bromophenol Blue Toxic Dyes.

Silver nanoparticles (Ag-NPs) are attracting great attention for their use in various applications, along with methods for their green and facile production. In this study, we present a new eco-friendly approach based on the use of Euphorbia balsamifera extract (EBE) in the green synthesis of silver nanoparticles (Ag-NPs), which are then applied as a reducing and stabilizing agent for the efficient removal of water-based reactive dyes such as bromocresol green (BCG) and bromophenol blue (BPB). The as-prepared Ag-NPs are quasi-spherical in shape, with an average diameter of 20-34 nm. Diverse characterization methods, including X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) analysis, were used to analyze these Ag-NPs. The results reveal that water-soluble biomolecules in the Euphorbia balsamifera extract play an important role in the formation of the Ag-NPs. The removal of toxic dyes was studied under varied operational parameters such as Ag-NP dosage, initial dye concentration, pH, stirring time, and temperature. Under the optimum investigated conditions, nearly 99.12% and 97.25% of the bromocresol green and bromophenol blue dyes, respectively, were removed. Both BCG and BPB adsorption were found to adhere to pseudo-second-order kinetics (r22 = 1 and 0.995) and fit the Langmuir isotherm models well (R12 = 0.998 and 0.994), with maximal monolayer adsorption capacities of 20.40 and 41.03 mg/g, respectively. Their adsorption processes were observed to be intrinsically endothermic. The results confirm the potential of the Euphorbia balsamifera extract as a low-cost, nontoxic, and eco-friendly natural resource for the synthesis of Ag-NPs that may be useful in the remediation of hazardous dye-contaminated water sources.

Eco-friendly and solar light-active Ti-Fe2O3 ellipsoidal capsules' nanostructure for removal of herbicides and organic dyes.

In this work, Ti-doped Fe2O3 with hollow ellipsoidal capsules nanostructure has been prepared in a green manner using plant extract (flax seed). This new green hematite nanomaterial has been evaluated as photocatalyst for water treatment by testing its activity for degradation of bromophenol blue dye (BPB) and 2,4-dichlorophenoxy acetic acid (2,4-D) herbicide. For a better understanding of the green material properties, a comparison with the pristine Fe2O3 nanospheres previously prepared by the same procedure is included. Structural and optical properties of the green prepared materials are studied. The results revealed the success doping of Ti4+ at Fe3+ site, without forming any of TiO2 phases. It was also found that the Ti doping resulted in the reduction of the band gap of Fe2O3 as well as changing the morphology. The Ti-doped Fe2O3 nanomaterial exhibited an enhanced photocatalytic activity either for BPB dye or for 2,4-D degradation with more than 2 times higher rate than that using pristine Fe2O3.

Study of the integument that covering back and stinger of the freshwater stingray Potamotrygon rex (Chondricthyes, Potamotrygonidae).

The objective of this study was to describe the histology and histochemistry of the integument covering the back and stinger of the freshwater stingray Potamotrygon rex, endemic to the Middle Upper Tocantins River. The species has a dark back and yellowish circular spots that extend to the tail, which has one to two stings located in the median portion of the tail. Through histological study it was observed that the epithelia of the back and stinger are composed of non-keratinized stratified pavement epithelial tissue, and are organized in three layers: basal, intermediate and superficial. The differences between the tissues are related to the cell types that compose them. The back is organized with epithelial cells, mucus cells, granulocyte cells and chromatophores. The mucus cells are distributed in different layers along the animal's back, influencing the thickness of the tissue. The tissue that covers the stinger is composed of epithelial cells, chromatophores and specialized cells in protein synthesis. In the histochemistry, the stinger epithelial cells were stained with Bromophenol Blue, especially those of the intermediate layer, which were called specialized cells. In the back the epithelial cells were stained with Bromophenol Blue, Alcian Blue and PAS, and the mucous cells with PAS. In both tissues the presence of protein reserves was detected, areas so called because they are stained strongly with Bromophenol Blue. The results show that the stinger presents activity directed to the production of proteins, and that the back is organized to produce different components, which constitute the cuticle that covers the animal's body.

A proposed synergetic mechanism for metal fume fever involving ZnO and Fe3O4 nanoparticles.

Metal fumes fever (MFF) is an inflammatory condition, whose mechanism is yet unclear, associated with the inhalation of metal fumes, particularly zinc. In this study we investigate experimentally the hypothesis of a two-step mechanism of MFF onset: (1) the photocatalytic production of airborne hydrogen peroxide (H2O2) via ZnO and (2) the production of hydroxyl radicals (HOׄ) through Fenton reaction via magnetite (Fe3O4) nanoparticles. Photocatalysis and Fenton reaction products were measured using a multiscattering-enhanced absorbance device and assessing the degradation of bromophenol blue with microplate photometry, respectively. We observed that in the presence of UV, ZnO produces 3 to 4-times more H2O2 than UV alone or that non-UV irradiated ZnO. In the presence of biologically-relevant ligands, we also measured a Fenton reaction at physiological pH with either Fe(II), Fe(III) or Fe3O4 nanoparticles. Our results support the hypothesis of a two-step mechanism of MFF onset, in which the prior presence of Fe in the lungs exacerbates the oxidative stress, triggered by the photocatalysis of ZnO, a situation that could occurs when welding galvanized steel. More broadly, this raises the question of the role of the Fenton mechanism in respiratory exposure to metal particles and its possible contribution to other lung diseases.

Polyethylene glycol capped copper ferrite porous nanostructured materials for efficient photocatalytic degradation of bromophenol blue.

Three different types (blank, annealed, and functionalized) of copper ferrite nanoparticles (CuFe2O4) were synthesized by the co-precipitation method. The CuFe2O4 NPs were characterized by Fourier transform infrared (FTIR), Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Energy-dispersive X-ray spectroscopy (EDX) techniques. FTIR analysis confirmed that 3-APTES is successfully grafted on the surface of CuFe2O4 NPs. XRD results show the amorphous nature of blank CuFe2O4 NPs, and crystalline structure was observed for annealed and functionalized CuFe2O4 NPs. XRD results revealed that crystallite size ranges from 23.6 to 34.6 nm. SEM micrographs of blank CuFe2O4 NPs show the irregular shape and size of the nanostructure. The spherical and strongly linked structure was seen in the micrograph of functionalized CuFe2O4 NPs. EDX analysis revealed the nanostructure composed of Fe, Cu, O, and a small percentage of Si. The photocatalytic degradation efficiency of synthesized CuFe2O4 NPs was examined under UV irradiation in an aqueous medium against bromophenol blue (BPB) dye. The effect of different parameters such as irradiation time and pH on the photodegradation of BPB dye was studied by all three types of CuFe2O4 photocatalyst. Results show that the maximum photocatalytic degradation efficiency was observed for functionalized CuFe2O4 nanoparticles that degraded 98% of BPB dye in the acidic medium at pH = 1. The optimum contact time for dye degradation was 120 min by synthesized photocatalyst. Photodegradation performance of blank and annealed CuFe2O4 NPs is less than 90%. The synthesized CuFe2O4 NPs were recycled and reused, which shows good photocatalytic degradation efficiency up to 4 consecutive cycles. The kinetic model displayed that degradation reaction followed pseudo 1st order kinetics. The blank, annealed, and functionalized CuFe2O4 NPs have turnover numbers of 10.7x10 (Mudhoo et al., 2019), 12.9x10 (Mudhoo et al., 2019), and 22.2x10 (Mudhoo et al., 2019) (kg-1 sec-1) accordingly. In conclusion, all results revealed the high efficiency of prepared photocatalyst for tested hazardous dye from wastewater and encouraged more work on photodegradation of organic pollutants from wastewater.

Novel sustainable composites made of car's waste and sodium titanate for the efficient photocatalytic removal of the bromophenol blue dye: study under solar and UV-Vis light.

In this research, W-doped sodium nanotube titanate (NaTNT) nanoparticles were used for the photocatalytic degradation of the bromophenol blue (BPB) dye. The NaTNT powder was mixed with car's tire powder (TP) to enhance its light absorption or was supported on recycled car's air filters (AFs) to facilitate its removal from the cleaned water after the degradation of the BPB. The SEM analysis indicated that the NaTNT nanoparticles and the TP had sizes in the range of 150-325 nm and 8-37 µm, respectively. Both powders were also studied by X-ray diffraction and found that the sodium titanate corresponds to the Na2Ti6O13 with monoclinic phase, while the TP is formed by rubber, silicon, ZnS, and ZnO. The photocatalytic activity of the NaTNT powder was evaluated for the degradation of BPB dye (20 ppm) and obtained a maximum degradation of 95 and 80% under UV-Vis and natural solar light, respectively, after 4 h of irradiation. For the NaTNT + TP composite mixture, the maximum degradation was 87 and 68% under UV-Vis and solar light, respectively. The NaTNT and NaTNT + TP powders were supported on the AFs to form the AF + NaTNT and AF + NaTNT + TP composites. Those ones produced maximum degradation of 86% and 74% (under UV-Vis light), respectively. Besides, several initial pHs were tested for the contaminated water and determined that the maximum degradation of BPB (93-95%) is reached for the pHs of 3 and 7. Reuse experiments (3 cycles) revealed that the diminution of the BPB degradation percentage was 23% and 20% for the NaTNT and NaTNT + TP powders, respectively. Overall, it was demonstrated that the wasted car's air filters can be used as a support for photocatalytic powders, and this combination of AF + powder degrades the BPB with high efficiency.

Spectrophotometric quantitative analysis of lesinurad using extractive acid dye reaction based on greener selective computational approach.

Computational studies introduce an integral approach for finding greener methods through testing solvents for reactions and extractions. Lesinurad is a novel selective uric acid reabsorption inhibitor prescribed for the treatment of chronic gout. Computational calculations were achieved to choose the best acid dye used for sensitive visible spectrophotometric determination of lesinurad. The calculations were performed using Gaussian 03 software based on density functional theory method with B3LYP/6-31G(d) basis set. The obtained results revealed that bromophenol blue was preferred for lesinurad than other acid dyes based on the higher calculated interaction energy. The described method was based on the reaction of lesinurad with the theoretically selected acid dye bromophenol blue to form a yellow ion-pair complex. The absorption spectra showed maximum sharp peaks at 418 nm. Different factors affecting the reaction were optimized. Beer's law was demonstrated over the concentration range of 2-12 µg/mL lesinurad. The described reaction was utilized for the spectrophotometric determination of lesinurad in pure form and in the pharmaceutical preparation. The greenness of the described method was assessed using four different tools namely, the national environmental method index, the analytical eco-scale, the green analytical procedure index and the novel analytical greenness metric. The proposed method seemed to be superior to the reported HPLC method with respect to the metrics of the greenness characters.

Spectrophotometric quantitative analysis of remdesivir using acid dye reagent selected by computational calculations.

Remdesivir was approved by the Food and Drug Administration for the treatment of COVID -19 in hospitalized adult and pediatric patients. Application of computational calculations for choosing the sensitive reagent in spectrophotometric quantitative analysis is very limited. Computational and theoretical studies were used for choosing the best acid dye for selective visible spectrophotometric quantitative analysis of remdesivir. The calculations were performed using Gaussian 03 software with the density functional theory method using B3LYP/6-31G(d) basis set. The theoretical studies revealed that bromophenol blue is a better match for remdesivir than other acid dyes due to the higher calculated interaction energy. The proposed method was based on the reaction of remdesivir with the computationally selected acid dye bromophenol blue to form a yellow ion-pair complex. The spectra showed absorption peaks at 418 nm. Various factors affecting the reaction were optimized. The method was successfully applied for the determination of remdesivir in the pharmaceutical preparation with good accuracy and precision. Beer's law was observed in the concentration range of 2-12 µg/mL of remdesivir. The proposed reaction was used as a basis for the spectrophotometric determination of remdesivir in pure form and in the pharmaceutical preparation.

Smartphone-Assisted Protein to Creatinine Ratio Determination on a Single Paper-Based Analytical Device.

Proteinuria is a condition in which an excessive amount of protein is excreted in urine. It is, among others, an indicator of kidney disease or risk of cardiovascular disease. Rapid and reliable diagnosis and monitoring of proteinuria is of great importance for both patients and their physicians. For that reason, a paper-based sensor for proteinuria diagnosis was designed, optimized, and validated utilizing smartphone-assisted signal acquisition. In the first step, a few commonly employed protein assays were optimized and compared in terms of analytical performance on paper matrix. The tetrabromophenol blue method was selected as the one providing a sufficiently low limit of detection (39 mg·L-1) on the one hand and appropriate long-term stability (up to 3 months) on the other hand. The optimized assay was employed for protein-to-creatinine ratio (PCR) determination on a single paper-based sensor. For both analytes the linear ranges were within the clinically relevant range. The analytical usefulness of the developed sensors was demonstrated by a PCR recovery study in artificial urine. The obtained PCR recoveries were from ca. 80 to 150%.

One-pot synthesis of zinc oxide nanoparticles via chemical precipitation for bromophenol blue adsorption and the antifungal activity against filamentous fungi.

In this research, zinc oxide nanoparticles (ZnONPs) were prepared via a facile one-pot chemical precipitation approach and applied in the adsorption of bromophenol blue (BRB) and as antifungal agents against the filamentous fungi and plant pathogens; Alternaria alternata CGJM3078, Alternaria alternata CGJM3006 and Fusarium verticilliodes CGJM3823. The ZnONPs were characterized by the UV-Vis, FTIR, XRD, TGA, BET, SEM, TEM, and EDX techniques, which showed efficient synthesis. The characteristics ZnO UV-Vis absorption band was observed at 375 nm, while the XRD showed an average ZnONPs crystalline size of 47.2 nm. The SEM and TEM images showed an irregular shaped and aggregated porous structure of 65.3 nm average-sized ZnONPs. The TGA showed 22.9% weight loss at 800 °C indicating the high thermal stability of ZnONPs, while BET analysis revealed a surface area, pore volume and pore diameter of 9.259 m2/g, 0.03745 cm3/g and 9.87 nm respectively. The Freundlich, pseudo-second-order, and intra-particle diffusion models showed R2 > 0.9494 and SSE < 0.7412, thus, exhibited the best fit to the isotherm and kinetics models. Thermodynamics revealed feasible, endothermic, random, and spontaneous adsorption of BRB onto the synthesized ZnONPs. The antifungal assay conducted depicts strong antifungal activities against all three tested fungi. Noticeably, ZnONPs (0.002-5 mg/mL) showed maximum activities with the largest zone of inhibition against A. alternata CGJM 3006 from 25.09 to 36.28 mm. This was followed by the strain F. verticilliodes CGJM 3823 (range from 23.77 to 34.77 mm) > A. alternata CGJM3078 (range from 22.73 to 30.63 mm) in comparison to Bleach 5% (positive control). Additionally a model was proposed based on the possible underlying mechanisms for the antifungal effect. This research demonstrated the potent use of ZnONPs for the adsorption of BRB and as effective antifungal agents.

Development and validation of spectrophotometric methods for estimation of antimigraine drug eletriptan hydrobromide in pure form and pharmaceutical formulations.

OBJECTIVES: The present study aims to develop and validate four simple, sensitive, reproducible, and low-cost spectrophotometric methods for the determination of antimigraine drug (eletriptan hydrobromide) in pure form and pharmaceutical formulations. METHODS: The methods are based on the formation of yellow colored ion-pair complex between eletriptan hydrobromide and four acid dyes, namely, bromocresol purple (BCP), bromocresol green (BCG), bromophenol blue (BPB), and bromothymol blue (BTB) with absorption maxima at 410, 420, 414 and 416nm, respectively. Several parameters such as pH, buffer type and volume, reagent volume, sequence of addition and effect of extracting solvent were optimized. RESULTS: Under the optimum experimental conditions, beer's law is obeyed over the concentration ranges of 1.0-20 and 1.0-16µgmL-1 for (BCP or BCG) and (BPB or BTB), respectively with good correlation coefficients (0.9995-0.9999). The apparent molar absorptivity and Sandell's sensitivity values are reported for all methods. The limit of detection (LOD) and the limit of quantification (LOQ) values are found to be 0.27, 0.28, 0.25, and 0.30µgmL-1 and 0.90, 0.93, 0.83, and 1.0µgmL-1 for BCP, BCG, BPB and BTB, respectively. The stoichiometric ratio of the formed ion-pair complexes was found to be 1:1 (drug: reagent) for all methods. CONCLUSION: The developed methods were successfully applied for the determination of eletriptan hydrobromide in pharmaceutical formulations with good accuracy and precision. Statistical comparison of the results was performed using Student's t-test and variance ratio F-test at the 95% confidence level and there was no significant difference between the reported and proposed methods regarding accuracy and precision. Further, the validity of the proposed methods was confirmed by recovery studies via standard addition method.

Colorimetric detection of residual quaternary ammonium compounds on dry surfaces and prediction of antimicrobial activity using bromophenol blue.

Controlling and monitoring the residual activity of quaternary ammonium compounds (QACs) are critical for maintaining safe yet effective levels of these agents in the environment. This study investigates the utility of bromophenol blue (BPB) as a safe, rapid and user-friendly indicator to detect in situ residual QACs dried on hard, non-porous surfaces, as well a means to assess their antimicrobial efficacy. At pH 7, BPB has a purple colour which turns blue upon its complexation with QACs such as didecyldimethylammonium chloride (DDAC). BPB itself has no antimicrobial properties up to 400 ppm. Within the range of 0-400 ppm, BPB colour change was tied to specific DDAC antimicrobial performances with a detection threshold of 100 ppm. BPB concentration and application volume could be adjusted such that a colour shift from purple to blue correlated with a set percent reduction (>99·9%) in test bacteria (Staphylococcus aureus and Klebsiella aerogenes). The BPB solutions developed in this study yielded similar colour shifts on polycarbonate and stainless steel surfaces and did not cross-react with chemical ingredients commonly found in sanitizers and disinfectant products. Overall, this study suggests that BPB provides a simple solution to safely monitor the post-application level and biocidal activity of residual dried QACs on surfaces.

Biogenic and chemically synthesized Solanum tuberosum peel-silver nanoparticle hybrid for the ultrasonic aided adsorption of bromophenol blue dye.

This work was aimed at the synthesis of a hybrid (STpe-AgNP), obtained by impregnation of silver nanoparticles (AgNP) onto Solanum tuberosum peel (STpe), for the ultrasonic assisted adsorption of bromophenol blue (BB) dye. SEM, FTIR, XRD, EDX, TGA and BET techniques were used to characterize the adsorbents. The XRD, SEM and EDX confirmed successful impregnation of AgNPs onto STpe to form the hybrid. The AgNPs impregnated onto the hybrid were found to be water stable at various pH values of 2.0-9.0. Chi-square (χ2 < 0.024) and linear regression (R2 > 0.996) showed that the Freundlich model was best fitted among the isotherm models, corroborated by the oriented site model. Kinetic analysis conformed to the intraparticle diffusion and pseudo-first-order rate equations, while thermodynamics displayed a physical, spontaneous and endothermic adsorption process. The presence of competing Pb(II), Ni(II), Cd(II) and Zn(II) metal ions in solution interfered with the adsorption of BB onto the biosorbents. In terms of reusability, STpe and STpe-AgNP showed BB desorption of 91.3% and 88.5% respectively, using NaOH as eluent. Ultra-sonication significantly enhanced the adsorption of BB by both adsorbents, but the impregnation of AgNPs only slightly improved adsorption of the dye from the simulated wastewater. This study also illustrated that pristine STpe biomass waste is a cheap viable option for the decontamination of BB from water.

Lysozyme crystals dyed with bromophenol blue: where has the dye gone?

Protein crystals can easily be coloured by adding dyes to their mother liquor, but most structures of these protein-dye complexes remain unsolved. Here, structures of lysozyme in complex with bromophenol blue obtained by soaking orthorhombic and tetragonal crystals in a saturated solution of the dye at different pH values from 5.0 to 7.5 are reported. Two different binding sites can be found in the lysozyme-bromophenol blue crystals: binding site I is located near the amino- and carboxyl-termini, while binding site II is located adjacent to helices α1 (residues 4-15) and α3 (residues 88-100). In the orthorhombic crystals soaked at pH 7.0, binding of the dye takes place in both sites without significant changes in the unit cell. However, soaking tetragonal crystals with bromophenol blue results in two different complexes. Crystals soaked at pH 5.5 (HEWL-T1) show a single dye molecule bound to site II, and the crystals belong to space group P43212 without significant changes in the unit cell (a = b = 78.50, c = 37.34 Å). On the other hand, crystals soaked at pH 6.5 in the presence of imidazole (HEWL-T2) show up to eight molecules of the dye bound to site II, and display changes in space group (P212121) and unit cell (a = 38.00, b = 76.65, c = 84.86 Å). In all of the structures, the dye molecules are placed at the surface of the protein near to positively charged residues accessible through the main solvent channels of the crystal. Differences in the arrangement of the dye molecules at the surface of the protein suggest that the binding is not specific and is mainly driven by electrostatic interactions.

Characterization of a thermotolerant and acidophilic mannanase producing Microbacterium sp. CIAB417 for mannooligosachharide production from agro-residues and dye decolorization.

Mannanases are ubiquitous enzymes and are being explored for diverse industrial applications. In this study, a novel bacterial strain Microbacterium sp. CIAB417 was identified and characterized for extracellular production of mannanase. Microbacterium sp. CIAB417 was found to produce maximum mannanase after 36 h of incubation at 37 °C. Mannanase produced by the isolate was observed for maximum activity at optimum pH of 6 and optimum temperature of 50 °C. Crude mannanase was found to be capable of producing mannooligosachharides (MOS) by hydrolyzing hemicellulose from locust bean gum and Aloe vera. The produced MOS was characterized and found to be mixture of mannobiose to mannohexose units. Mannanase was also explored for decolorization of dyes. Bromophenol blue and coomassie blue R-250 were observed to be decolorized to the extent of 45.40 and 42.75%, respectively. Hence, the identified bacterial strain producing mannanase could be of great significance for applications in food and textile industry.

Live cell fluorescent stain of bacterial curli and biofilm through supramolecular recognition between bromophenol blue and CsgA.

Identification of curli-specific dyes for biofilm communities of microorganisms is an important task. We describe here a curli fluorescent light-up probe called bromophenol blue, which binds to curli via recognizing CsgA. This platform may provide a new perspective for the research on biofilm, amyloid disease and living materials.

Removal of bromophenol blue anionic dye from water using a modified exuviae of Hermetia illucens larvae as biosorbent.

Organic dyes originating from liquid effluents from the textile industries are harmful to the environment. They are toxic and reduce the penetration of light into aquatic environments. In this study, a biosorbent was produced from the exuviae of Hermetia illucens (Linnaeus) larvae and used to remove organic anionic dyes from an aqueous medium. The solids were characterized in terms of thermal stability, chemical structure, morphology, and porosity using thermogravimetric (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and N2 adsorption-desorption. There were studied the effects of pH and dosage of the adsorbent on the adsorption of the bromophenol blue dye, used as a model molecule. The adsorption kinetics was studied with Lagergren's pseudo-first-order rate model. The maximum adsorbed amount was 571 mg g-1 according to Langmuir's model. The adsorption process was evaluated as exothermic and spontaneous and was classified as physical adsorption. The prepared biosorbent was tested in five consecutive adsorption cycles achieving 99% dye removal at each stage. This demonstrated the maintenance of adsorption efficiency and desorption capacity. These results suggest that prepared biosorbent have potential applications in the treatment of effluents from textile industries.