Review on Microbial Sources, Production, Purification and Potential Industrial Applications of Laccases

Laccase (EC 1.10.3.2) is a multicopper blue oxidase which are involved in the oxidation of a broad range of organic substrates, including phenols, polyphenols, anilines, and even certain inorganic compounds by a one-electron transfer mechanism. Laccases are widely distributed in bacteria, fungai, insects and higher plants. There are mainly two production techniques for cultivation of laccase such as submersed fermentation and solid- state fermentation. This paper briefly discuss the effect of carbon source, effect of nitrogen source, effect of inducers, effects of surfactants, effect of agitator, influence of metal ions and  use of agro-industrial waste in production medium. The paper also discussed the purification techniques such as ammonium sulphate precipitation for extraction purpose followed by dialysis and ion-exchange chromatography as well characterization techniques. Laccases are known to show application ranging from pharmaceutical industries to textile sector as well as in biosensor development. View Article DOI: 10.47856/ijaast.2021.v08i12.00

Fabrication of cellulose nanocrystals/carboxymethyl cellulose/zeolite membranes for methylene blue dye removal: understanding factors, adsorption kinetics, and thermodynamic isotherms

This study introduces environmentally-friendly nanocellulose-based membranes for AZO dye (methylene blue, MB) removal from wastewater. These membranes, made of cellulose nanocrystals (CNCs), carboxymethyl cellulose (CMC), zeolite, and citric acid, aim to offer eco-friendly water treatment solutions. CNCs, obtained from sugarcane bagasse, act as the foundational material for the membranes. The study aims to investigate both the composition of the membranes (CMC/CNC/zeolite/citric acid) and the critical adsorption factors (initial MB concentration, contact time, temperature, and pH) that impact the removal of the dye. After systematic experimentation, the optimal membrane composition is identified as 60% CNC, 15% CMC, 20% zeolites, and 5% citric acid. This composition achieved a 79.9% dye removal efficiency and a 38.3 mg/g adsorption capacity at pH 7. The optimized membrane exhibited enhanced MB dye removal under specific conditions, including a 50 mg adsorbent mass, 50 ppm dye concentration, 50 mL solution volume, 120-min contact time, and a temperature of 25°C. Increasing pH from neutral to alkaline enhances MB dye removal efficiency from 79.9% to 94.5%, with the adsorption capacity rising from 38.3 mg/g to 76.5 mg/g. The study extended to study the MB adsorption mechanisms, revealing the chemisorption of MB dye with pseudo-second-order kinetics. Chemical thermodynamic experiments determine the Freundlich isotherm as the apt model for MB dye adsorption on the membrane surface. In conclusion, this study successfully develops nanocellulose-based membranes for efficient AZO dye removal, contributing to sustainable water treatment technologies and environmental preservation efforts

Plant mediated synthesis of flower-like Cu2O microbeads from Artimisia campestris L. extract for the catalyzed synthesis of 1,4-disubstituted 1,2,3-triazole derivatives

This study presents a novel method for synthesizing 1,4-disubstituted 1,2,3-triazole derivatives through a one-pot, multi-component addition reaction using flower-like Cu2O microbeads as a catalyst. The flower-like Cu2O microbeads were synthesized using an aqueous extract of Artimisia Campestris L. This extract demonstrated the capability to reduce and stabilize Cu2O particles during their initial formation, resulting in the formation of a porous flower-like morphology. These Cu2O microbeads exhibit distinctive features, including a cubic close-packed (ccp) crystal structure with an average crystallite size of 22.8 nm, bandgap energy of 2.7 eV and a particle size of 6 µm. Their catalytic activity in synthesizing 1,4-disubstituted 1,2,3-triazole derivatives was investigated through systematic exploration of key parameters such as catalyst quantity (1, 5, 10, 15, 20, and 30 mg/mL), solvent type (dimethylformamide/H2O, ethanol/H2O, dichloromethane/H2O, chloroform, acetone, and dimethyl sulfoxide), and catalyst reusability (four cycles). The Cu2O microbeads significantly increased the product yield from 20% to 85.3%. The green synthesis and outstanding catalytic attributes make these flower-like Cu2O microbeads promising, efficient, and recyclable catalysts for sustainable and effective chemical transformations

Exploring the potential of a Ephedra alata leaf extract: Phytochemical analysis, antioxidant activity, antibacterial properties, and green synthesis of ZnO nanoparticles for photocatalytic degradation of methylene blue

Ephedra alata leaf extracts have therapeutic properties and contain various natural compounds known as phytochemicals. This study assessed the phytochemical content and antioxidant effects of a Ephedra alata leaf extract, as well as zinc oxide (ZnO) nanoparticle production. The extract contained phenolic acids, including vanillic acid, chlorogenic acid, gallic acid, p-coumaric acid, vanillin and rutin. Its total phenolic content and total flavonoid content were 48.7 ± 0.9 mg.g-1 and 1.7 ± 0.4 mg.g-1, respectively. The extract displayed a DPPH inhibition rate of 70.5%, total antioxidant activity of 49.5 ± 3.4 mg.g-1, and significant antimicrobial activity toward Gram-positive and negative bacteria. The synthesized ZnO nanoparticles had spherical shape, crystallite size of 25 nm, particle size between 5 and 30 nm, and bandgap energy of 3.3 eV. In specific conditions (90 min contact time, pH 7, and 25°C), these nanoparticles efficiently photodegraded 87% of methylene blue, suggesting potential applications for sustainable water treatment and pollution control

Tribological Performance for Steel–Steel Contact Interfaces Using Hybrid MWCNTs/Al₂O₃ Nanoparticles as Oil-Based Additives in Engines

Numerous problems occur during engine operation, such as start-up, lack of lubrication, and overheating, resulting in engine components’ wear, power loss, and fuel consumption. Nanomaterials dispersed in engine oil can play an important role in improving the tribological properties of oil lubricants. This study investigated the influence of multi-walled carbon nanotubes (MWCNTs) and aluminum oxide nanoparticles (Al2O3 NPs) as nano-additives for lubricants. Different engine oil samples were loaded with 0.5–2.0 wt% Al2O3 NPs and 0.5–1.0 wt% MWCNTs and compared with unmodified oil. The tribological performance of the nano lubricants was investigated using the four-ball test method. In addition, the wear scar in the engine was evaluated using 3D micrographs and scanning electron microscopy (SEM). The results of the sliding surfaces with hybrid MWCNTs/Al2O3 NPs showed better friction performance and wear resistance. The coefficient of friction (COF) and wear scar width were improved by 47.9% and 51.5%, respectively, compared with unmodified oil

Tribological Performance for Steel–Steel Contact Interfaces Using Hybrid MWCNTs/Al2O3 Nanoparticles as Oil-Based Additives in Engines

Numerous problems occur during engine operation, such as start-up, lack of lubrication, and overheating, resulting in engine components’ wear, power loss, and fuel consumption. Nanomaterials dispersed in engine oil can play an important role in improving the tribological properties of oil lubricants. This study investigated the influence of multi-walled carbon nanotubes (MWCNTs) and aluminum oxide nanoparticles (Al2O3 NPs) as nano-additives for lubricants. Different engine oil samples were loaded with 0.5–2.0 wt% Al2O3 NPs and 0.5–1.0 wt% MWCNTs and compared with unmodified oil. The tribological performance of the nano lubricants was investigated using the four-ball test method. In addition, the wear scar in the engine was evaluated using 3D micrographs and scanning electron microscopy (SEM). The results of the sliding surfaces with hybrid MWCNTs/Al2O3 NPs showed better friction performance and wear resistance. The coefficient of friction (COF) and wear scar width were improved by 47.9% and 51.5%, respectively, compared with unmodified oil

Review of recent research on flexible multifunctional nanopapers

International audienceTraditional paper and papermaking have struggled with a declining market during the last few decades. However, the incorporation of nanotechnology into papermaking has brought possibilities to develop low-cost, biocompatible and flexible products with sophisticated functionalities. The functionality of nanopapers emerges from the intrinsic properties of the nanofibrous network, the additional loading of specific nanomaterials (NMs), or the additional deposition and patterning of thin films of nanomaterials on the paper surface. A successful development of functional nanopapers requires understanding how the nanopaper matrix, nanofillers, nanocoating pigments, nanoprinting inks, processing additives and manufacturing processes all interact to provide the intended functionality. This review addresses the emerging area of functional nanopapers. This review discusses flexible and multifunctional nanopapers, NMs being used in nanopaper making, manufacturing techniques, and functional applications that provide new important possibilities to utilize papermaking technology. The interface where NM research meets traditional papermaking has important implications for food packaging, energy harvesting and energy storage, flexible electronics, low-cost devices for medical diagnostics, and numerous other areas

Review: nanoparticles and nanostructured materials in papermaking

International audienceThe introduction of nanoparticles (NPs) and nanostructured materials (NSMs) in papermaking originally emerged from the perspective of improving processing operations and reducing material consumption. However, a very broad range of nanomaterials (NMs) can be incorporated into the paper structure and allows creating paper products with novel properties. This review is of interdisciplinary nature, addressing the emerging area of nanotechnology in papermaking focusing on resources, chemical synthesis and processing, colloidal properties, and deposition methods. An overview of different NMs used in papermaking together with their intrinsic properties and a link to possible applications is presented from a chemical point of view. After a brief introduction on NMs classification and papermaking, their role as additives or pigments in the paper structure is described. The different compositions and morphologies of NMs and NSMs are included, based on wood components, inorganic, organic, carbon-based, and composite NPs. In a first approach, nanopaper substrates are made from fibrillary NPs, including cellulose-based or carbon-based NMs. In a second approach, the NPs can be added to a regular wood pulp as nanofillers or used in coating compositions as nanopigments. The most important processing steps for NMs in papermaking are illustrated including the internal filling of fiber lumen, LbL deposition or fiber wall modification, with important advances in the field on the in situ deposition of NPs on the paper fibers. Usually, the manufacture of products with advanced functionality is associated with complex processes and hazardous materials. A key to success is in understanding how the NMs, cellulose matrix, functional additives, and processes all interact to provide the intended paper functionality while reducing materials waste and keeping the processes simple and energy efficient