Antibiotic resistance profile of halophilic microorganisms isolated from tannery effluent

80-86Halophiles are defined as organisms showing considerable growth at salt concentrations higher than 100 g L-1. Based on the halophilicity, halophiles can be broadly classified as slightly, moderately or extremely halophilic depending on their requirement for NaCl. Halophilic microorganisms, metabolically diversified, comprising Archaea, Bacteria, and Eucarya, are found distributed all over the world in hypersaline environments including drained soak liquor and brine cured hides. Plasmids mediating resistance to antimicrobial agents have been found in many halophilic bacteria examined so far. For the purpose of protection of salt cured hides, adequate knowledge and exposure related to characteristics of halophilic bacteria is very important as halophilic microorganisms secrete bacterial collagenases responsible for collagen damage in the form of ‘Red heat’. All the halophilic bacteria isolated from the drained soak liquor used in these experiments were proved to be motile, aerobic and extremely pleomorphic Gram negative organisms. The growth curve of the halophilic bacteria showed slower growth profile at 37°C compared to E. coli. Effective plasmid isolation further strengthened the antibiotic resistance of the halophiles. Analysis of drained soak liquor was followed to examine the related important features of the halophilic species. Optimum salinity of media and pleomorphic Gram-negative nature of halophiles were found as causative factors of insensitivity to antimicrobial agents (AMA). It was found that darkness and low temperature would resist ‘Red heat’ on hides

Structures, Properties, and Performances—Relationships of Polymeric Membranes for Pervaporative Desalination

For the fulfilment of increasing global demand and associated challenges related to the supply of clean-and-safe water, PV has been considered as one of the most attractive and promising areas in desalinating salty-water of varied salinities. In pervaporative desalination, the sustainability, endurance, and structural features of membrane, along with operating parameters, play the dominant roles and impart paramount impact in governing the overall PV efficiency. Indeed, polymeric- and organic-membranes suffer from several drawbacks, including inferior structural stability and durability, whereas the fabrication of purely inorganic membranes is complicated and costly. Therefore, recent development on the high-performance and cost-friendly PV membrane is mostly concentrated on synthesizing composite- and NCP-membranes possessing the advantages of both organic- and inorganic-membranes. This review reflects the insights into the physicochemical properties and fabrication approaches of different classes of PV membranes, especially composite- and NCP-membranes. The mass transport mechanisms interrelated to the specialized structural features have been discussed. Additionally, the performance potential and application prospects of these membranes in a wide spectrum of desalination and wastewater treatment have been elaborated. Finally, the challenges and future perspectives have been identified in developing and scaling up different high-performance membranes suitable for broader commercial applications

In Situ Allocation of a Monomer in Pectin‑<i>g</i>‑Terpolymer Hydrogels and Effect of Comonomer Compositions on Superadsorption of Metal Ions/Dyes

Pectin-<i>g</i>-(sodium acrylate-<i>co</i>-3-(<i>N</i>-isopropylacrylamido) sodium propanoate-<i>co</i>-<i>N</i>-isopropylacrylamide) interpenetrating polymer networks (PANIPNs) were synthesized through systematic multistage optimization of equilibrium swelling ratio by response surface methodology for individual and/or synergistic removal(s) of cationic safranine (SF), anionic methyl orange, and M­(II/III), such as Hg­(II), Cd­(II), and Cr­(III). The relative effects of copolymer compositions on ligand-selective adsorption, strong/weak H-bonds, thermal stabilities, crystallinity, surface properties, swelling abilities, cross-link densities, network parameters, hydrophilic–hydrophobic characteristics, and adsorption capacities (ACs) were measured through extensive microstructural analyses of adsorbed and/or unadsorbed PANIPN41 and PANIPN21 bearing sodium acrylate and <i>N</i>-isopropylacrylamide (SA/NIPAm) in 4:1 and 2:1 ratios, respectively, using Fourier transform infrared, ¹H and ¹³C NMR, X-ray photoelectron spectroscopy, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy, along with measuring lower critical solution temperature, % gel content (% GC), % −COOH, and pH_PZC. Extensive UV–vis measurements were carried out at varying copolymer compositions, initial pH (pH_i), and dyes, interpreted considering monomer–dimer and azonium–ammonium equilibrium of dye, dye–dye complexation, ligand-selective PANIPNs–dye adduct formation, π–π stacking interactions, and orientation effect of dyes. Thermodynamically feasible chemisorption processes showed the maximum ACs of 127.61, 96.78, 103.36, and 99.41 mg g^–1 for SF, Hg­(II), Cd­(II), and Cr­(III), respectively, under optimum conditions

Excited-State Energy Transfer-Associated Dual Emission of Light-Emitting Polymers Containing Sulfonated Graphene Oxide for Sensing of pH, Co(II), and Bi(III)

The design, synthesis, optimization, and development of an excited-state energy transfer (ESET)-assisted dual-light emission hybrid polymeric sensor are very much challenging, particularly when the polymer is purely aliphatic and bears nonconventional heteroatomic subfluorophores. In this work, aliphatic light-emitting polymers (LEPs) are synthesized from dimethylaminoethyl methacrylate and maleic acid monomers having −C(O)OCH2–, −N(CH3)2, and −C(O)OH/–C(O)O– subfluorophores. In aliphatic LEPs, hydrogen bond associated strong supramolecular networks facilitate n → π* transmissions and dual excitation dual emission. The optimum incorporation of subfluorophores in LEP5 is supported by Fourier transform infrared (FTIR) and nuclear magnetic resonance spectroscopies, thermogravimetric profiles, and aggregation enhanced emission (AEE) studies. Thereafter, the sulfonated graphene oxide (SGO) nanoparticle is incorporated in the optimum LEP5 to fabricate hybrid light-emitting polymers (HLEPs) having increased size/surface area, noncovalent interactions, and electronic distributions. In HLEPs, electron rich polar −C(O)OH/–C(O)O– and −SO3H/–SO3– functionalities increase hydrogen bonding and dipole–dipole interactions. Among HLEPs, HLEP3 having the maximum aggregating tendency and emission capacity is optimized by AEE studies and FTIR, Raman, powder X-ray diffraction (PXRD), and thermogravimetric analyses. In the aggregation-associated ESET phenomenon of HLEP3, the SGO nanoparticle acts as an energy acceptor. The ESET-associated single-excitation dual emissions are supported by the absorption and emission maxima of HLEP3-aggregate and HLEP3, respectively; excitation spectra; and average lifetimes in time correlated single photon count studies. The aggregations of HLEP3 are supported by dynamic light scattering (DLS) studies, scanning electron microscopy photomicrographs, and UV–vis spectra. The dual-emission phenomena of HLEP3 and its pH-sensitive subfluorophores −N(CH3)2, −C(O)OH/–C(O)O–, and −SO3H/–SO3– are responsible for precise ratiometric pH sensing within 8.0–11.0. The reversibility test and PXRD data of HLEP3 at different pH values indicate the stability of HLEP3 in acidic, neutral, and basic media. The dual-light emissions facilitate rapid sensing and detections of Co(II) and Bi(III) with limits of detection below the WHO-recommended values in both aqueous and nonaqueous media. The strong coordinations of Co(II) and Bi(III) with −C(O)O–/–SO3H/–SO3– of HLEP3 and HLEP3-aggregate, respectively, are confirmed by UV–vis, FTIR, and Raman spectroscopies along with the DLS measurements