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In this study, a comprehensive investigation of doping of sol-gel silica with DMG and other chelating agents is provided at room temperature using infrared spectroscopy, elemental analysis, SEM, EDS and powder XRD. Sol-gel silica was doped with dimethyl glyoxime (DMG), ethylenediamine (EDA), 1,10-Phenanthroline (Phen), dithizone (DZ), and sulfanilamide (SB) to investigate the sorption of Ni(II) from aqueous media. It is observed that the chelating agents are encapsulated by the pores of the xerogel from where they interact with the metal ions by ion exchange and chelation mechanism. Nickel complexes of the chelating agents were also synthesized. Sol-gel silica was doped with metal complexes for comparison with sol-gel silica with sorbed metal ions. Ni(II) in metal complex was compared with that in functionalized silica from EDS of both samples. The batch adsorption experiments were performed at room temperature and neutral pH. The developed method can be applied on large scale removal of Ni(II) using silica and chelating agents from cheap natural sources. The sorption process was completed within 5 minutes and 0.1 N HNO3 resulted in complete desorption of metal ions. The regenerated sorbent can be reused six times with negligible loss of sorption capacity. Sol-gel silica was functionalized with DMG and other chelating agents for the removal of Ni(II) from aqueous media. Sol-gel silica was also functionalized using Ni complexes of the chelating agents for comparison. DMG functionalized sol-gel silica showed high sorption capacity and fast desorption of Ni(II) at room temperature and neutral pH. The sorption process was completed in 5 minutes. 0.1 N HNO3 resulted in complete desorption of metal ions. The regenerated sorbent can be reused six times with negligible loss of sorption capacity. The developed method can be applied on large scale removal of Ni(II) if we use silica and chelating agents obtained from cheap natural sources. [ABSTRACT FROM AUTHOR]

Background: Lactic acid bacteria (LAB) are considered as GRAS (generally recognized as safe) and being used extensively as bio-preservatives. Bacteriocins, the metabolites of LAB, belong to a diverse family of naturally synthesized antimicrobial peptides. Objective: Strain improvement for enhanced bacteriocin production by physical and chemical mutagenesis. Methods: The bacterial strain was identified by 16S rDNA sequence analysis and improved by ultraviolet and ethidium bromide mutation. The resultant bacteriocin was biochemically characterized, purified and analyzed for mass determination. Results: Among mutants of identified Lactobacillus acidophilus MS1, the UV6 (ultraviolet mutant) revealed 3400 AU bacteriocin activity with 42% survival rate and EB5 (ethidium bromide mutant) exhibited 4020 AU with 28% survival rate. Bacteriocin of 6.5 kDa was purified by cation exchange and gel exclusion chromatography. It was found to be thermally stable at 100°C for 30 min and maintained the stability up to 121°C. The activity was monitored in a wide range of pH (4–9). Conclusion: Being resistant to several biochemical parameters, the bacteriocins have an effective incorporation in food, forage and pharmacy. There is a need to engage more efforts to explore novel bacteriocins and multifarious applications. [ABSTRACT FROM AUTHOR]

Schiff bases have been successfully doped with sol- gel silica by our group. There are only few previous reports on doping of Schiff bases with sol- gel silica. This study pertains to novel synthesis of 4-(2-(2-hydroxybenzylideneamino) ethyl) benzenesulfonamide (a Schiff base) doped in xerogel silica, its characterization by FTIR, thermogravimetry, scanning electron micrography and porosimetry studies besides its application in adsorption of chromium (III) and lead (II) ions from aqueous media. The large Schiff base molecules are entrapped by the pores of xerogel. Likewise, metal ions in aqueous solution make complex with Schiff base by either ion exchange or chelation through the pores. Doping of Schiff base in xerogel gives a porous and stable surface working at high temperature. Doping of Schiff base provides a convenient approach of tailoring the surface properties of mesoporous silica by organic functionalization. Both blank and Schiff based xerogels exhibit ordered mesoporous structures and hydrophilic properties responsible for ion exchange or chelation mechanism. Adsorption phenomenon was studied by noting solution pH, contact time and concentration of adsorbate. The equilibration time was as swift as it completed within ten min. Finally, 0.1 N HNO3 was employed for desorption of metal ions followed by regeneration and periodic recycling of synthesized xerogels in this study. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the morphological behavior of polyurethane elastomers (PUEs) by modifying the soft segment chain length. This was achieved by increasing the soft segment molecular weight (Mn = 400–4000 gmol−1). In this regard, polycaprolactone diol (PCL) was selected as the soft segment, and 4,4′-cyclohexamethylene diisocyanate (H12MDI) and 1,6-hexanediol (HDO) were chosen as the hard segments. The films were prepared by curing polymer on Teflon surfaces. Fourier transform infrared spectroscopy (FTIR) was utilized for functional group identification in the prepared elastomers. FTIR peaks indicated the disappearance of −NCO and −OH groups and the formation of urethane (NHCOO) groups. The morphological behavior of the synthesized polymer samples was also elucidated using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The AFM and SEM results indicated that the extent of microphase separation was enhanced by an increase in the molecular weight of PCL. The phase separation and degree of crystallinity of the soft and hard segments were described using X-ray diffraction (XRD). It was observed that the degree of crystallinity of the synthesized polymers increased with an increase in the soft segment's chain length. To evaluate hydrophilicity/hydrophobicity, the contact angle was measured. A gradual increase in the contact angle with distilled water and diiodomethane (38.6°–54.9°) test liquids was observed. Moreover, the decrease in surface energy (46.95–24.45 mN/m) was also found to be inconsistent by increasing the molecular weight of polyols. [ABSTRACT FROM AUTHOR]

Bacteriocins are antimicrobial peptides synthesized by lactic acid bacteria. These are well known for their anti-bacterial activity in fermented foods and extend the shelf-life and safety of food items. The optimum bacteriocin production was predicted from Lactobacillus acidophilus MS1 using Box-Behnken experimental design. The maximum bacteriocin activity titre of 2600AU/mL was observed with 30 °C, pH 6 and 18 h incubation time. The results derived from response surface methodology (RSM) regression equation indicated that the initial pH of the model system influencing stronger than other physical variables at 95% confidence level. Moreover, quadratic and interaction effects of these variables were also found significant. A monomeric peptide of 6.5 kDa was purified to 59.1-fold from crude sample using ion exchange and gel filtration chromatography. Purified peptide showed strong inhibitory activity against biofilm produced by Bacillus cereus, a food born pathogen. Box-Behnken design can be used for large scale production of bacteriocin from novel strain of Lactobacillus acidophilus MS1 that might be used as a preservative and non-allergic antibiotic in food as well as in pharmaceuticals. • Bacteriocins are synthesized by lactic acid bacteria for safety of food items. • Bacteriocin production was projected from L. acidophilus MS1 using Box-Behnken design. • Maximum bacteriocin activity was observed with 30 °C temperature, pH 6 and 18 h incubation. • RSM exhibited initial pH of the model system has strong influence at 95% confidence level. • Monomeric peptide of 6.5 kDa was purified to 59.1-fold using chromatographic methods. [ABSTRACT FROM AUTHOR]

Background: Betti bases are pharmaceutically and synthetically important scaffolds due to their diverse range of biological activities and applications in key synthetic transformations in organic synthesis., Objective: This work has been sought to contribute to the development, design, and implementation of an improved green methodology with higher atom economy and lower E-factor values for the synthesis of Betti bases., Methods: To realize our objectives, we screened out different catalysts and reaction conditions using one-pot multicomponent modified Mannich reaction/Betti reaction by employing 2-naphthol, benzaldehyde and pyrrolidine as model substrates., Results: The developed methodology afforded functionalized Betti bases in 60-100% yields via FeCl 3 •6H 2 O catalyzed one-pot multi-component Betti reaction under neat conditions at 110 °C (5-15 min) using several aromatic aldehydes and secondary amines., Conclusion: A facile synthetic methodology with higher atom economy and lower E-factor values to synthesize Betti bases via FeCl 3 •6H 2 O catalyzed one-pot multicomponent Betti reaction of 2-naphthol, aromatic aldehydes, and secondary amines under neat conditions at 110 °C has been reported. The developed methodology offers various advantages, such as excellent yields (60-100%), short reaction time (5-15 min), wide substrate scope (12 examples), green reaction conditions, use of readily available catalyst, and easy purification (without column chromatography)., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)