Notes

Discerning biosorption device involving methylene azure with a story and also multiple-use glucose beet pulp cellulose/sodium alginate/iron hydroxide composite hydrogel.
V.The present study is first of its kind that focuses upon the extraction of bromelain from pineapple core waste and stabilising it as insoluble cross-linked aggregates. The influence of process variables such as the choice of precipitant, type of cross-linker, concentration of cross-linker and the reaction time for cross-linking step was investigated upon the activity recovery of bromelain cross-linked aggregates. The optimization of this biocatalyst preparation specifically recovered 87% of the enzymatic activity available in pineapple core waste by ammonium sulphate (60%, w/v) precipitation followed by cross-linking for 4 h with 80 mM glutaraldehyde. Cross-linked bromelain aggregates were thermally more stable and exhibited higher pH stability in comparison to free bromelain. The cross-linked bromelain aggregates exhibited higher operational stability in different organic solvents at 4 °C. The highest operational stability (% stability given in parenthesis) was observed in acetone (100%) followed by hexane (53.6%), ethyl acetate (39.6%), ethanol (32.5%) and chloroform (14.9%). The kinetic studies revealed higher Km value (5.45 mM) after the formation of cross-linked bromelain aggregates as compared to free bromelain (5.04 mM) with almost similar Vmax values. find more Cross-linked bromelain aggregates also showed significant reusability characteristics with an activity retention of >85% after 5-time cycles. Such recyclability of bromelain cross-linked aggregates could lead to potential industrial applications in both food and non-food sector. In addition, the present extraction method avoids costs related to purification and expensive immobilization carriers. Two accessory loop regions that are present in numerous variants of New Delhi metallo-β-lactamases (NDM) are important for the enzymatic activity. The first one is a flexible loop L3 that is located near the active site and is thought to play an important role in the catalytic process. The second region, Ω loop is located close to a structural element that coordinates two essential zinc ions. Both loops are not involved in any specific interactions with a substrate. Herein, we investigated how the length and hydrophobicity of loop L3 influence the enzymatic activity of NDMs, by analyzing mutants of NDM-1 with various deletions/point mutations within the L3 loop. We also investigated NDM variants with sequence variations/artificial deletions within the Ω loop. For all these variants we determined kinetic parameters for the hydrolysis of ampicillin, imipenem, and a chromogenic cephalosporin (CENTA). None of the mutations in the L3 loop completely abolished the enzymatic activity of NDM-1. Our results suggest that various elements of the loop play different roles in the hydrolysis of different substrates and the flexibility of the loop seems necessary to fulfill the requirements imposed by various substrates. Deletions within the Ω loop usually enhanced the enzymatic activity, particularly for the hydrolysis of ampicillin and imipenem. However, the exact role of the Ω loop in the catalytic reaction remains unclear. In our kinetic tests, the NDM enzymes were inhibited in the β-lactamase reaction by the CENTA substrate. We also present the X-ray crystal structures of the NDM-1, NDM-9 and NDM-12 proteins. Drug resistance to bacteria becomes an emerging intractable problem, therefore, developing novel antibacterial agents has become urgently needed. Herein, a bio-inspired design strategy was adopted to synthesize a series of beetle-like macromolecule of multiple quaternary ammonium salts (QASs), which was designed with different cationic charge densities and numbers of hexadecane chains by adjusting their different quaternization degree (QD). It was found that the fabricated fabric surface with them exhibited controllable and outstanding antibacterial and bacterially anti-adhesive properties. More importantly, the antibacterial efficiency was demonstrated to be enhanced with the increasing of QD, and related to the zeta potential, and surface tension. Additionally, the proposed bacterially anti-adhesive model of action revealed the "resisting effect" of hydration layer which greatly resisted the adhesion of bacteria. V.Green finishing formulations have established an important place in textile dyeing and finishing industry. The use of plant extracts along with chemical metallic mordants is reported to increase colour values and improve fastness properties. However, metal salts as mordants constantly pose environmental and human health risks. The purpose of this work is to examine and extend the knowledge of natural dyeing technology considering the use of biological macromolecule chitosan (CS) to increase dye uptake, fastness and impart functional properties. The cotton was pre-coated with chitosan using pad-dry method and optimal chitosan concentrations were selected by evaluating the colour spectrometry data in term of CIEL*a*b* values. The chemical nature of the extract was characterized by UV-Vis, Fourier-transform infrared spectroscopy (FT-IR) and Thermogravimetric analysis (TGA) whereas dyed samples were analysed by Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX) with mapping analysis, FT-IR, and TGA. Results showed that the aqueous extract of Citrus sinensis peel yielded interestingly shades all lying in yellow- red quadrant of CIELa*b* colour space with acceptable grades of wash and dry-wet fastness properties. This study reveals important information to understand synergism between two natural products in imparting semi durable antioxidant and antibacterial activity against E. coli and S. aureus, and thus offers full potential to be used in natural dyeing technology. Thermoplastic starch (TPS) foams was prepared by melt extrusion process and the effects of polyvinyl alcohol (PVA) and glycerol/water plasticizer contents on the physical and cellular properties of these foams were investigated. All TPS/PVA blended foams showed more uniform cellular morphology, lower density and higher cell density than the TPS foam. The density of TPS foam decreased about 70%, and cell density increased up to 60-fold by adding 20% PVA. In addition to the positive effect of the PVA on improving processability and cellular uniformity, it also acted as a polymeric plasticizer and adding it allowed to decrease another low molecular weight plasticizer content in TPS/PVA blends. As a result by statistical analysis significant improvements in expansion ratio (256%), cell density (60 times), and lower moisture absorption (60%) were achieved.
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