Coloured and low conductive fabrics by in situ laccase-catalysed polymerization

Thiadiazol ligand-based laccase-like nanozymes with a high Cu+ ratio for efficient removal of tetracyclines through polymerization

A promising water treatment technology involves inducing the polymerization of organic pollutants to form corresponding polymers, enabling rapid, efficient, and low CO2 emission removal of these pollutants. However, there is currently limited research on utilizing polymerization treatment technology for removing tetracyclines from water. In this study, we synthesized a laccase-mimic nanozyme (Cu-ATZ) with a high Cu+ ratio using 2-amino-1,3,4-thiadiazole as a ligand inspired by natural laccase. The Cu-ATZ exhibited enhanced resistance to more severe application conditions and improved stability compared to natural laccase, thereby demonstrating a broader range of potential applications. The excellent catalytic properties of Cu-ATZ enabled the nanozyme to be used in the polymerization process to remove tetracyclines from water. In order to simulate actual antibiotic pollution of water bodies, tetracyclines were added to the water from sewage treatment plants. Following Cu-ATZ treatment of the water sample, the chemical oxygen demand (COD) content was found to have decreased by over 80 %. In conclusion, this study presented a novel approach for tetracycline elimination from water.

Recent Advancements in Enhancing Antimicrobial Activity of Plant-Derived Polyphenols by Biochemical Means

Plants are a reservoir of phytochemicals, which are known to possess several beneficial health properties. Along with all the secondary metabolites, polyphenols have emerged as potential replacements for synthetic additives due to their lower toxicity and fewer side effects. However, controlling microbial growth using these preservatives requires very high doses of plant-derived compounds, which limits their use to only specific conditions. Their use at high concentrations leads to unavoidable changes in the organoleptic properties of foods. Therefore, the biochemical modification of natural preservatives can be a promising alternative to enhance the antimicrobial efficacy of plant-derived compounds/polyphenols. Amongst these modifications, low concentration of ascorbic acid (AA)–Cu (II), degradation products of ascorbic acid (DPAA), Maillard reaction products (MRPs), laccase–mediator (Lac–Med) and horse radish peroxidase (HRP)–H2O2 systems standout. This review reveals the importance of plant polyphenols, their role as antimicrobial agents, the mechanism of the biochemical methods and the ways these methods may be used in enhancing the antimicrobial potency of the plant polyphenols. Ultimately, this study may act as a base for the development of potent antimicrobial agents that may find their use in food applications.

Investigation of reactive Blue 19 biodegradation and byproducts toxicity assessment using crude laccase extract from Trametes versicolor

Crude laccase potency on biodegradation and detoxification of Reactive blue 19 (RB-19) were demonstrated, along with prediction of degradation mechanisms, pathways and byproducts analysis. Trametes versicolor, cultured on pampas grass inflorescence (Cortaderia selloana), yielded the best crude laccase activity (15.36 U/g). 10 U CLE activities demonstrated a biodegradation yield (85%) in 210 min, at pH 4, 50 °C and 200 mg/L RB-19 concentrations. Evolution of a brown color that absorbed maximally at 478 nm was observed during biodegradation. Two methods were adopted for byproducts extraction, three methods for toxicity analysis and four models for kinetic parameters (K_m and V_max) determination. 2-ethylanthracene, 2-hydroxycyclohexa-2,4-dien-1-one, 2(4-methylphenyl)-ethan-1-amine, 1-[6-hydroperoxy-4,5-bis(sulfooxy)oxan-3-yl]triaza-1,2-dien-2-ium, naphthalene-2,7-disulfonic acid and N-[(5-oxooxolan-2-yl)methyl]acetamide were detected as toxic byproducts. Brown color evolution was due to 1,1,1-triethyl-3-(methoxycarbonyl)-2,2-dioxo-2λ6-diazathian-1-ium (methoxycarbonyl sulfanyl-triethylammonium hydroxide) inner salt. Increase in color density (light to dark brown) was a function of byproduct(s) biodegradation and polymerization. RB-19 and byproduct acute toxicities were decreased significantly (98% - 6.91%). Kinetic parameters K_m (18.05 mg/L) and V_max (0.31 mg/L. min^-1) from the four kinetic models demonstrated higher affinity of CLE to RB-19. CLE yielded a catalytic activity (V_max/K_m =0.017 min^-1) demonstrating the flexibility of CLE active site to RB-19 binding over commercial laccase.

Applications of Microbial Laccases: Patent Review of the Past Decade (2009–2019)

There is a high number of well characterized, commercially available laccases with different redox potentials and low substrate specificity, which in turn makes them attractive for a vast array of biotechnological applications. Laccases operate as batteries, storing electrons from individual substrate oxidation reactions to reduce molecular oxygen, releasing water as the only by-product. Due to society’s increasing environmental awareness and the global intensification of bio-based economies, the biotechnological industry is also expanding. Enzymes such as laccases are seen as a better alternative for use in the wood, paper, textile, and food industries, and they are being applied as biocatalysts, biosensors, and biofuel cells. Almost 140 years from the first description of laccase, industrial implementations of these enzymes still remain scarce in comparison to their potential, which is mostly due to high production costs and the limited control of the enzymatic reaction side product(s). This review summarizes the laccase applications in the last decade, focusing on the published patents during this period.

Synthesizing Polyaniline With Laccase/O2 as Catalyst

The polymerization of aniline to polyaniline (PANI) can be achieved chemically, electrochemically or enzymatically. In all cases, the products obtained are mixtures of molecules which are constituted by aniline units. Depending on the synthesis conditions there are variations (i) in the way the aniline molecules are connected, (ii) in the average number of aniline units per molecule, (iii) in the oxidation state, and (iv) in the degree of protonation. For many possible applications, the synthesis of electroconductive PANI with para-N-C-coupled aniline units in their half-oxidized and protonated state is of interest. This is the emeraldine salt form of PANI, abbreviated as PANI-ES. The enzymatic synthesis of PANI-ES is an environmentally friendly alternative to conventional chemical or electrochemical methods. Although many studies have been devoted to the in vitro synthesis of PANI-ES by using heme peroxidases with added hydrogen peroxide (H2O2) as the oxidant, the application of laccases is of particular interest since the oxidant for these multicopper enzymes is molecular oxygen (O2) from air, which is beneficial from environmental and economic points of view. In vivo, laccases participate in the synthesis and degradation of lignin. Various attempts of synthesizing PANI-ES with laccase/O2 in slightly acidic aqueous media from aniline or the linear aniline dimer PADPA (p-aminodiphenylamine) are summarized. Advances in the understanding of the positive effects of soft dynamic templates, as chemical structure guiding additives (anionic polyelectrolytes, micelles, or vesicles), for obtaining PANI-ES-rich products are highlighted. Conceptually, some of these template effects appear to be related to the effect "dirigent proteins" exert in the biosynthesis of lignin. In both cases intermediate radicals are formed enzymatically which then must react in a controlled way in follow-up reactions for obtaining the desired products. These follow-up reactions are controlled to some extent by the templates or specific proteins.