The history of colour is fascinating from a social and artistic viewpoint because it shows the way; use; and importance acquired. The use of colours date back to the Stone Age (the first news of cave paintings); colour has contributed to the social and symbolic development of civilizations. Colour has been associated with hierarchy; power and leadership in some of them. The advent of synthetic dyes has revolutionized the colour industry; and due to their low cost; their use has spread to different industrial sectors. Although the percentage of coloured wastewater discharged by the textile; food; pharmaceutical; cosmetic; and paper industries; among other productive areas; are unknown; the toxic effect and ecological implications of this discharged into water bodies are harmful. This review briefly shows the social and artistic history surrounding the discovery and use of natural and synthetic dyes. We summarise the environmental impact caused by the discharge of untreated or poorly treated coloured wastewater to water bodies; which has led to physical; chemical and biological treatments to reduce the colour units so as important physicochemical parameters. We also focus on laccase utility (EC 1.10.3.2), for discolouration enzymatic treatment of coloured wastewater, before its discharge into water bodies. Laccases (p-diphenol: oxidoreductase dioxide) are multicopper oxidoreductase enzymes widely distributed in plants, insects, bacteria, and fungi. Fungal laccases have employed for wastewater colour removal due to their high redox potential. This review includes an analysis of the stability of laccases, the factors that influence production at high scales to achieve discolouration of high volumes of contaminated wastewater, the biotechnological impact of laccases, and the degradation routes that some dyes may follow when using the laccase for colour removal

The first traces of Tetracycline (TE) were detected in human skeletons from Sudan and Egypt, finding that it may be related to the diet of the time, the use of some dyes, and the use of soils loaded with microorganisms, such as Streptomyces spp., among other microorganisms capable of producing antibiotics. However, most people only recognise authors dating between 1904 and 1940, such as Ehrlich, Domagk, and Fleming. Antibiotics are the therapeutic option for countless infections treatment; unfortunately, they are the second most common group of drugs in wastewaters worldwide due to failures in industrial waste treatments (pharmaceutics, hospitals, senior residences) and their irrational use in humans and animals. The main antibiotics problem lies in delivered and non-prescribed human use, use in livestock as growth promoters, and crop cultivation as biocides (regulated activities that have not complied in some places). This practice has led to the toxicity of the environment as antibiotics generate eutrophication, water pollution, nutrient imbalance, and press antibiotic resistance. In addition, the removal of antibiotics is not a required process in global wastewater treatment standards. This review aims to raise awareness of the negative impact of antibiotics as residues and physical, chemical, and biological treatments for their degradation. We discuss the high cost of physical and chemical treatments, the risk of using chemicals that worsen the situation, and the fact that each antibiotic class can be transformed differently with each of these treatments and generate new compounds that could be more toxic than the original ones; also, we discuss the use of enzymes for antibiotic degradation, with emphasis on laccases.

Laccases (E.C. 1.10.3.2) are multicopper oxidases of great importance in the industry due to their non-specificity and high oxidative potential. Laccases are useful to bleach synthetic dyes, oxidize phenolic compounds and degrade pesticides, among others. Hence, the objective of this work was to optimize low cost culture media for recombinant (rPOXA 1B) laccase production from Pleurotus ostreatus in Pichia pastoris. To this end, low cost nitrogen sources were studied, such as malt extract, isolated soy protein and milk serum. Following, two central composite designs (CCD) were performed. In CCD-1 different concentrations of glucose USP (0-13.35 gL^-1), protein isolated soy protein (5-25 gL^-1), malt extract (3.5-17.5 gL^-1) and (NH₄)₂SO₄ (1.3-6.5 gL^-1) were evaluated. In CCD-2 only different concentrations of glucose USP (7.9-22 gL^-1) and isolated soy protein (15.9-44.9 gL^-1) were evaluated. CCD-2 results led to a One Factor Experimental design (OFED) to evaluate higher isolated soy protein (20-80 gL^-1) concentrations. In all designs, (CCD-1, CCD-2 and OFED) CuSO₄ (0.16 gL^-1) and chloramphenicol (0.1 gL^-1) concentrations remained unchanged. For the OFED after sequential statistical optimization, an enzyme activity of 12,877.3 ± 481.2 UL^-1 at 168 h was observed. rPOXA 1B activity increased 30.54 % in comparison with CCD-2 results. Final composition of optimized media was: 20 gL^-1 glucose USP, 50 gL^-1 isolated soy protein 90 % (w/w), 11.74 gL^-1 malt extract, and 4.91 gL^-1 (NH₄)₂SO₄. With this culture media, it was possible to reduce culture media costs by 89.84 % in comparison with improved culture media previously described by our group.

Antibiotics present a pressing environmental challenge as emerging pollutants due to their persistence and role in promoting antibiotic-resistant bacteria. To model the utilization of Ganoderma lucidum GlLCC1 laccase in degrading antibiotics, a 3D homology model of GILCC1, based on Lentinus tigrinus mushroom laccase, was utilized. Five broad-spectrum WHO-designated antibiotics with molecular weights between 100 and 500 Da were selected. Molecular dynamics simulations were conducted at pH 3.0 and 7.0 to evaluate the interactions between GILCC1 and antibiotics in a TIP3P water box, with system behaviour assessed at 300 °K using an NPT assembly. ABTS (2,2ʹ-Azino-bis (3-ethylbenzthiazoline-6-sulfonic Acid)) served as the comparison molecule. The binding free energy indicated a strong affinity between 3D GILCC1 and various ligands. At pH 3.0, GILCC1 exhibited significant Gibbs free energy (ΔG), indicating a high affinity for Levofloxacin (LVX; −8.2 kcal mol⁻¹), Sulfisoxazole (SFX; −7.8 kcal mol⁻¹), Cefuroxime (CXM; −7.5 kcal mol⁻¹), Cephradine (CFD; −7. 5 kcal mol⁻¹), ABTS (−7.6 kcal mol⁻¹), and Tetracycline (TE; −7.5 kcal mol⁻¹), attributed to pocket topology and interactions such as hydrogen bonds and van der Waals forces. Electron transfer in GILCC1 involved a chain of residues, including His³⁹⁵ and Phe²³⁹. Although the affinity decreased at pH 7.0, the potential of GILCC1 to degrade antibiotics remained plausible. This study accurately predicted the behaviour of the laccase-antibiotic system, providing atomic-level insights into molecular interactions and emphasizing the importance of experimental assays and assessments of antibiotic degradation in wastewater, considering various chemical compounds. The use of ABTS as a mediator was suggested to enhance molecule affinity. Graphical abstract

Laccases (E.C. 1.10.3.2) are glycoproteins widely distributed in nature. Their structural conformation includes three copper sites in their catalytic center, which are responsible for facilitating substrate oxidation, leading to the generation of H₂O instead of H₂O₂. The measurement of laccase activity (UL⁻¹) results may vary depending on the type of laccase, buffer, redox mediators, and substrates employed. The aim was to select the best conditions for rGILCC 1 and rPOXA 1B laccases activity assay. After sequential statistical assays, the molecular dynamics proved to support this process, and we aimed to accumulate valuable insights into the potential application of these enzymes for the degradation of novel substrates with negative environmental implications. Citrate buffer treatment T2 (CB T2) (pH 3.0 ± 0.2; λ_420nm, 2 mM ABTS) had the most favorable results, with 7.315 ± 0.131 UL⁻¹ for rGILCC 1 and 5291.665 ± 45.83 UL⁻¹ for rPOXA 1B. The use of citrate buffer increased the enzyme affinity for ABTS since lower K_m values occurred for both enzymes (1.49 × 10⁻² mM for rGILCC 1 and 3.72 × 10⁻² mM for rPOXA 1B) compared to those obtained in acetate buffer (5.36 × 10⁻² mM for rGILCC 1 and 1.72 mM for rPOXA 1B). The molecular dynamics of GILCC 1–ABTS and POXA 1B–ABTS showed stable behavior, with root mean square deviation (RMSD) values not exceeding 2.0 Å. Enzyme activities (rGILCC 1 and rPOXA 1B) and 3D model–ABTS interactions (GILCC 1–ABTS and POXA 1B–ABTS) were under the strong influence of pH, wavelength, ions, and ABTS concentration, supported by computational studies identifying the stabilizing residues and interactions. Integration of the experimental and computational approaches yielded a comprehensive understanding of enzyme–substrate interactions, offering potential applications in environmental substrate treatments.