Cytotoxic-Ag-Modified Eggshell Membrane Nanocomposites as Bactericides in Concrete Mortar.

Against the backdrop of escalating infrastructure budgets worldwide, a notable portion-up to 45%-is allocated to maintenance endeavors rather than innovative infrastructure development. A substantial fraction of this maintenance commitment involves combatting concrete degradation due to microbial attacks. In response, this study endeavors to propose a remedial strategy employing nano metals and repurposed materials within cement mortar. The methodology entails the adsorption onto eggshell membranes (ESM) of silver nitrate (ESM/AgNO3) or silver nanoparticles (ESM/AgNPs) yielding silver-eggshell membrane composites. Subsequently, the resulting silver-eggshell membrane composites were introduced in different proportions to replace cement, resulting in the formulation of ten distinct mortar compositions. A thorough analysis encompassing a range of techniques, such as spectrophotometry, scanning electron microscopy, thermogravimetric analysis, X-ray fluorescence analysis, X-ray diffraction (XRD), and MTT assay, was performed on these composite blends. Additionally, evaluations of both compressive and tensile strengths were carried out. The mortar blends 3, 5, and 6, characterized by 2% ESM/AgNO3, 1% ESM/AgNPs, and 2% ESM/AgNPs cement replacement, respectively, exhibited remarkable antimicrobial efficacy, manifesting in substantial reduction in microbial cell viability (up to 50%) of typical waste activated sludge. Concurrently, a marginal reduction of approximately 10% in compressive strength was noted, juxtaposed with an insignificant change in tensile strength. This investigation sheds light on a promising avenue for addressing concrete deterioration while navigating the balance between material performance and structural integrity.

Erratum to "Applications and immobilization strategies of the copper-centred laccase enzyme; a review"[Heliyon Volume 9, Issue 2, February 2023, Article e13156].

[This corrects the article DOI: 10.1016/j.heliyon.2023.e13156.].

Recent Advances in Applications of Oxidases and Peroxidases Polymer-Based Enzyme Biocatalysts in Sensing and Wastewater Treatment: A Review.

Oxidase and peroxidase enzymes have attracted attention in various biotechnological industries due to their ease of synthesis, wide range of applications, and operation under mild conditions. Their applicability, however, is limited by their poor stability in harsher conditions and their non-reusability. As a result, several approaches such as enzyme engineering, medium engineering, and enzyme immobilization have been used to improve the enzyme properties. Several materials have been used as supports for these enzymes to increase their stability and reusability. This review focusses on the immobilization of oxidase and peroxidase enzymes on metal and metal oxide nanoparticle-polymer composite supports and the different methods used to achieve the immobilization. The application of the enzyme-metal/metal oxide-polymer biocatalysts in biosensing of hydrogen peroxide, glucose, pesticides, and herbicides as well as blood components such as cholesterol, urea, dopamine, and xanthine have been extensively reviewed. The application of the biocatalysts in wastewater treatment through degradation of dyes, pesticides, and other organic compounds has also been discussed.

Synthesis and Assessment of Antimicrobial Composites of Ag Nanoparticles or AgNO3 and Egg Shell Membranes.

Engineering research has been expanded by the advent of material fusion, which has led to the development of composites that are more reliable and cost-effective. This investigation aims to utilise this concept to promote a circular economy by maximizing the adsorption of silver nanoparticles and silver nitrate onto recycled chicken eggshell membranes, resulting in optimized antimicrobial silver/eggshell membrane composites. The pH, time, concentration, and adsorption temperatures were optimized. It was confirmed that these composites were excellent candidates for use in antimicrobial applications. The silver nanoparticles were produced through chemical synthesis using sodium borohydride as a reducing agent and through adsorption/surface reduction of silver nitrate on eggshell membranes. The composites were thoroughly characterized by various techniques, including spectrophotometry, atomic absorption spectrometry, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy, as well as agar well diffusion and MTT assay. The results indicate that silver/eggshell membrane composites with excellent antimicrobial properties were produced using both silver nanoparticles and silver nitrate at a pH of 6, 25 °C, and after 48 h of agitation. These materials exhibited remarkable antimicrobial activity against Pseudomonas aeruginosa and Bacillus subtilis, resulting in 27.77% and 15.34% cell death, respectively.

Applications and immobilization strategies of the copper-centred laccase enzyme; a review.

Laccase is a multi-copper enzyme widely expressed in fungi, higher plants, and bacteria which facilitates the direct reduction of molecular oxygen to water (without hydrogen peroxide production) accompanied by the oxidation of an electron donor. Laccase has attracted attention in biotechnological applications due to its non-specificity and use of molecular oxygen as secondary substrate. This review discusses different applications of laccase in various sectors of food, paper and pulp, waste water treatment, pharmaceuticals, sensors, and fuel cells. Despite the many advantages of laccase, challenges such as high cost due to its non-reusability, instability in harsh environmental conditions, and proteolysis are often encountered in its application. One of the approaches used to minimize these challenges is immobilization. The various methods used to immobilize laccase and the different supports used are further extensively discussed in this review.