Removal and degradation of sodium diclofenac via radical-based mechanisms using S. sclerotiorum laccase

Development of an electrochemical sensor based on Ni-Bio-MOF and a molecular imprinted polymer for determination of diclofenac: electrochemical and DFT investigations

In this work, a metal-organic nickel framework (Ni-MOF) modified with a biological ligand (asparagine) (Ni-Bio-MOF) was synthesized by a hydrothermal method. Asparagine is believed to create defects on the surface of the MOF, thereby increasing its electrocatalytic activity. Then, a Diclofenac (DCF) polymer imprinted with l-methionine (PL-Met) was electrodeposited on a carbon paste electrode (CPE)/Ni-Bio-MOF and used as a new electrochemical sensor for highly selective and sensitive detection of DCF in biological and pharmaceutical samples. The Ni-Bio-MOF/MIP-PL-Met nanocomposite was characterized using the following techniques: FT-IR, FE-SEM, TEM, HR-TEM, XRD, XPS, and EDX. The electrochemical properties and performance of the sensor for the electrooxidation of DCF were assessed using CV, DPV, and EIS techniques. The electrochemical behavior of CPE/Ni-Bio-MOF/MIP-PL-Met and non-imprinted polymer (NIP) with an imprinting factor of 6.64 was investigated, and the influencing parameters in DCF measurement were optimized by cyclic voltammetry (CV). This modified sensor showed three dynamic ranges at 1.0-500.0 pM, 1.0-1000.0 nM, and 1.0-1000.0 μM of DCF with a limited detection (LOD) of 0.17 pM, sensitivity of 2015.5 μA μM-1 cm-2, relative standard deviation (RSD) of 3.3%, and reproducibility of 96.2%. Real samples of healthy human blood serum and DCF tablets were used to evaluate the practical application of the CPE/Ni-Bio-MOF/MIP-PL-Met electrochemical sensor. This method is simple, low-cost, with good limited detection, high sensitivity, and selectivity. The interactions of PL-Met with DCF were studied at the B3LYP/6-311++G(d,p) level of theory in both gaseous and aqueous phases. Additionally, the computational methodology investigated the thermodynamic stability of the proposed configurations and the role of hydrogen bonds in this system.

Laccase Functional Analysis: Substrates, Activity Assays, Challenges, and Prospects

Enzyme functional analysis is a multifaceted process that can be used for various purposes, such as screening for specific activities, as well as developing, optimising, and validating processes or final products. Functional analysis methods are crucial for assessing enzyme performance and catalytic properties. Laccase, a well-known blue multi-copper oxidase, holds immense potential in diverse industries such as pharmaceuticals, paper and pulp, food and beverages, textiles, and biorefineries due to its clean oxidation process and versatility in handling a wide range of substrates. Despite its prominence, the use of laccase encounters challenges in selecting appropriate functional analysis substrates and methods. This review delves into the substrates utilised in qualitative and quantitative techniques for laccase activity analysis. Although laccase catalyses mono-electron oxidation of aromatic hydroxyl, amine, and thiol compounds efficiently, using molecular oxygen as an electron acceptor, the review identifies limitations in the specificity of the commonly employed substrates, concerns regarding the stability of certain compounds and highlights potential strategies.

Laccase-based biocatalytic systems application in sustainable degradation of pharmaceutically active contaminants

The outflow of pharmaceutically active chemicals (PhACs) exerts a negative impact on biological systems even at extremely low concentrations. For instance, enormous threats to human and aquatic species have resulted from the widespread use of antibiotics in ecosystems, which stimulate the emergence and formation of antibiotic-resistant bacterial species and associated genes. Additionally, it is challenging to eliminate these PhACs by employing conventional physicochemical water treatment techniques. Enzymatic approaches, including laccase, have been identified as a promising alternative to eliminate a broad array of PhACs from water matrices. However, their application in environmental bioremediation is hindered by several factors, including the enzyme's stability and its location in the aqueous environment. Such obstacles may be surmounted by employing laccase immobilization, which enables enhanced stability (including inactivation caused by the substrate), and thus improved catalysis. This review emphasizes the potential hazards of PhACs to aquatic organisms within the detection concentration range of ngL-1 to µgL-1, as well as the deployment of laccase-based multifunctional biocatalytic systems for the environmentally friendly mitigation of anticancer drugs, analgesics/NSAIDs, antibiotics, antiepileptic agents, and beta blockers as micropollutants. This approach could reduce the underlying toxicological consequences. In addition, current developments, potential applications, and viewpoints have focused on computer-assisted investigations of laccase-PhACs binding at enzyme cavities and degradability prediction.

Laccases as Effective Tools in the Removal of Pharmaceutical Products from Aquatic Systems

This review aims to provide a comprehensive overview of the application of bacterial and fungal laccases for the removal of pharmaceuticals from the environment. Laccases were evaluated for their efficacy in degrading pharmaceutical substances across various categories, including analgesics, antibiotics, antiepileptics, antirheumatic drugs, cytostatics, hormones, anxiolytics, and sympatholytics. The capability of laccases to degrade or biotransform these drugs was found to be dependent on their structural characteristics. The formation of di-, oligo- and polymers of the parent compound has been observed using the laccase mediator system (LMS), which is advantageous in terms of their removal via commonly used processes in wastewater treatment plants (WWTPs). Notably, certain pharmaceuticals such as tetracycline antibiotics or estrogen hormones exhibited degradation or even mineralization when subjected to laccase treatment. Employing enzyme pretreatment mitigated the toxic effects of degradation products compared to the parent drug. However, when utilizing the LMS, careful mediator selection is essential to prevent potential increases in environment toxicity. Laccases demonstrate efficiency in pharmaceutical removal within WWTPs, operating efficiently under WWTP conditions without necessitating isolation.