Laccase from Trametes versicolor was applied to produce phenolic polymeric compounds with enhanced properties, using a wine lees extract as the phenolic source. The influence of the incubation time on the progress of the enzymatic oxidation and the yield of the formed polymers was examined. The polymerization process and the properties of the polymeric products were evaluated with a variety of techniques, such as high-pressure liquid chromatography (HPLC) and gel permeation chromatography (GPC), Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The enzymatic polymerization reaction resulted in an 82% reduction in the free phenolic compounds of the extract. The polymeric product recovery (up to 25.7%) and the molecular weight of the polymer depended on the incubation time of the reaction. The produced phenolic polymers exhibited high antioxidant activity, depending on the enzymatic oxidation reaction time, with the phenolic polymer formed after one hour of enzymatic reaction exhibiting the highest antioxidant activity (133.75 and 164.77 μg TE mg⁻¹ polymer) towards the ABTS and DPPH free radicals, respectively. The higher thermal stability of the polymeric products compared to the wine lees phenolic extract was confirmed with TGA and DSC analyses. Finally, the formed phenolic polymeric products were incorporated into chitosan films, providing them with increased antioxidant activity without affecting the films’ cohesion.

Large quantities of wine lees are produced annually by the wine industry. The high phenolic content makes them unsuitable for disposal in the environment or animal feed without a suitable treatment. In this study, wine lees were treated by Pleurotus ostreatus in submerged cultivation, producing a high-value biomass and elevated levels of laccase, an important industrial enzyme. Biomass and laccase production reached 21 g/L and 74,000 Units/L, respectively, at the optimal conditions of initial pH 6.0, 20% v/v wine lees, 30 g/L glucose, and 20 g/L yeast extract, while decolorization and dephenolization rates of the waste were over 90%. The mycelial biomass was rich in proteins and essential amino acids reaching up to 43% and 16% per dry weight, respectively. Carbohydrates and lipids were the second richest bioactive compound in biomass, with values of 29.4 ± 2.7% and 29.5 ± 2.7%, respectively. The crude laccase in the culture supernatant was purified via a simple two-step purification procedure by 4.4-fold with a recovery of 44%. The molecular weight of the enzyme was determined to be 62 kDa via SDS electrophoresis. Enzyme activity was optimal at pH 5.0 and 70 °C. The activation energy of the enzyme was calculated at a value of 20.0 ± 0.2 kJ/mol. The pH stability and thermostability of the purified laccase were studied. The enzyme was remarkably stable at pH 8.0 and at temperatures up to 40 °C. The thermal inactivation energy of the enzyme was determined to be 76.0 ± 1.2 kJ/mol. The thermodynamic parameters (ΔH*, ΔG*, and ΔS*) for the thermal deactivation of the purified laccase at a temperature range of 20–60 °C were: 73.8 ≤ ΔH* ≤ 74.3 kJ·mol⁻¹, 98.7 ≤ ΔG* ≤ 101.9 kJ·mol⁻¹, and −90.5 ≤ ΔS* ≤ −84.3 J·mol⁻¹·K⁻¹. Wine lees could be ideal substrates of fungal cultivation for laccase production and biomass with a high protein content in an eco-friendlier way.

In the present work, hybrid super-structured nanomaterials were synthesized by the combination of smectite nanoclays with various carbon-based nanomaterials (graphene oxide, carbon nanotubes and adamantylamine) and were used as nanosupports for the covalent and non-covalent immobilization of laccase from Trametes versicolor (TvL). TvL was successfully immobilized on these hybrid nanomaterials, achieving high immobilization yields (up to 85%), while its conformation remained unaltered upon immobilization. The apparent kinetic constants V_max and K_m of the immobilized enzymes strongly depended on the immobilization procedure and the composition of hybrid nanomaterials. Immobilized TvL preserved up to 50% of its initial activity after 24 h of incubation at 60 °C, while free enzyme was totally deactivated. The TvL-hybrid nanomaterials bioconjugates were efficiently applied for the degradation of various synthetic dyes, exhibiting excellent decolorization capacity, as well as high reusability (up to 11 successive catalytic cycles), providing insights into the use of these bionanoconjugates on applications with environmental, and industrial interest.

Wine lees, as one of the main by-products of winery wastes, is considered a rich source of bioactive compounds such as polyphenols. Recovery of such bioactive compounds would amplify the valorization of winery by-products, as well as promote their use in cosmetics and health applications. Towards this aim, the objective of this work is the recovery of phenolic compounds from wine lees by ultrasound-assisted extraction. The effect of extraction time, and ethanol content on the extraction yield of total phenolics was investigated, while the phenolic profile of the extract was monitored by GC-MS. Under the optimized conditions, the total phenolic content was calculated at 302.6 mg gallic acid equivalents g^− 1 dry extract; the dry extract was investigated for its biological activities, exhibiting excellent antioxidant and antimicrobial activity. Moreover, the extract was found to be a potent inhibitor of tyrosinase, elastase, collagenase, α-glucosidase, and α-amylase with IC₅₀ values of 53.3, 83.5, 82.7, 19.0, and 31.3 µg mL^− 1, respectively. Finally, the wine lees dry extract was incorporated into chitosan films, reinforcing the properties of the films, and providing them with excellent antioxidant activity. The results support that wine lees extract exhibits high antioxidant activity and can be used as a highly efficient inhibitor of enzymes with pharmaceutical and health interest. Moreover, the chitosan film enriched with wine lees extract is a promising material with high antioxidant potential and can lead to the development of novel food packaging films in the food industry. Graphical Abstract

Due to the prevalence of plastic-packaged foods, as well as the need for real-time food monitoring by consumers, reducing plastic pollution is essential for a healthier environment and nutrition. For these reasons, in this work, biodegradable pH-responsive chitosan films enriched with wine lees-derived anthocyanins were produced, and their pH sensitivity was thoroughly evaluated. Optimization of ultrasound-assisted extraction using ethanol/water mixtures as conventional solvents was conducted and the optimal conditions (regarding total anthocyanin content, total phenolic content, and antioxidant activity) were used to perform a screening of extraction with 16 different Natural Deep Eutectic Solvents. Among them, choline chloride: butylene glycol (1:4), at a concentration of 50% v/v in water, demonstrated the highest anthocyanin recovery and was selected for the preparation of the films. The resulting films exhibited an excellent colorimetric response to pH changes, with a color difference (ΔE) exceeding 6.8 at all tested pH values, improved mechanical properties, nearly zero UV permeability, and their antioxidant activity increased by up to 6.1-fold compared to pure chitosan film. Finally, the film was applied in detecting the freshness of pork meat, exhibiting a ΔE of 15.3. The results demonstrate that the developed film is a promising alternative for intelligent, bioactive, and biodegradable food packaging for food applications.