Biomass derived from green marine macroalgae Ulva sp. is considered a rich source of bioactive compounds. In the present study, we demonstrate the increased bioactivity of a phenolic-rich extract derived from green marine macroalgae Ulva intestinalis after its treatment with fungal laccases from Trametes versicolor and Agaricus bisporus. The phenolic composition of the extract, before and after its enzymatic treatment, was determined through several analytical methods. Furthermore, the antioxidant, enzyme-inhibitory, antimicrobial and cytotoxic activity of enzymatically modified and non-modified extracts was comparatively investigated. Depending on the laccase used, the enzyme-modified extracts exhibited different phenolic content and enhanced bioactivities compared to the non-treated ones. The enzymatically modified extracts presented enhanced antimicrobial, anti-lipoxygenase and anti-collagenase activities, and mild cytotoxicity. These results indicate that the proposed biocatalytic process could be applied to produce green macroalgal natural extracts with enhanced bioactivities paving the way for their implementation in the food, pharmaceutical, and cosmeceutical industries.

In the present work, methanolic extracts from thyme and dittany plants were prepared and characterized in terms of their polyphenolic content through analytical and spectrophotometric techniques. Rosmarinic acid, thymol and carvacrol were found to be the main components of the extracts, which were further biologically assessed for their antioxidant, anti-tyrosinase, anti-lipase and antibacterial activity against Gram-negative and Gram-positive bacteria. As found, thyme extracts exhibited superior antioxidant activity (SC₅₀ at 33.9 μg mL⁻¹), while dittany extracts inhibited the microbial growth to a great extent against Bacillus subtilis strain (MIC at 0.5 mg mL⁻¹) and E. coli strain (MIC at 2 mg mL⁻¹). Furthermore, the thyme extract was proven to strongly inhibit the activity of lipase from Candida rugosa (IC₅₀ at 63.9 μg mL⁻¹), comparable to the standard inhibitor orlistat, while its inhibitory effect against mushroom tyrosinase was weak. On the other hand, the dittany extract presented an inhibitory effect against the tested lipase (IC₅₀ over 500 μg mL⁻¹) and an activation effect against tyrosinase (at concentrations > 500 μg mL⁻¹). Additionally, molecular docking studies of the main compounds of the extracts showed that rosmarinic acid plays a crucial role on the inhibitory activity of the extracts against lipase, while thymol has a stronger effect on inhibiting tyrosinase. Furthermore, both extracts were employed in the preparation of gelatin-deep eutectic solvent (DES) hydrogels that were further studied for their antioxidant and antibacterial activity. The results showed that the incorporation of the extracts offered antibacterial properties to the biopolymer-based hydrogels and enhanced the antioxidant activity of gelatin up to 85%.

3D printed PLA has already been demonstrated for several biotechnological applications, including enzymes immobilization. The prerequisites for an efficient screening assay include using small volumes of reagents, low cost, and rapid screening of large numbers of compounds and extracts. Hence, assays based on microtiter plates are predominant. Thus, designing and fabricating scaffolds on a similar scale, which could serve as immobilization carriers, and their recruitment in inhibitors screening studies is of great significance, adding both enzyme stability and reuse potentiality of the biocatalytic system in assay merits. In this work, pancreatic lipase was immobilized on 3D-printed PLA microwells for enzyme inhibitor screening. XPS analysis demonstrated the successful modification of the PLA scaffolds. The immobilized enzyme displayed high levels of operational, thermal, and storage stability under the tested conditions. The IC50 values for PPL inhibition were calculated for Orlistat, a model lipase inhibitor, and olive leaf extract, a promising natural compound. This is the first study reporting the use of 3D-printed PLA wells with an immobilized enzyme for inhibitor screening assay.

3D printed PLA has already been demonstrated for several biotechnological applications, including enzymes immobilization. The prerequisites for an efficient screening assay include using small volumes of reagents, low cost, and rapid screening of large numbers of compounds and extracts. Hence, assays based on microtiter plates are predominant. Thus, designing and fabricating scaffolds on a similar scale, which could serve as immobilization carriers, and their recruitment in inhibitors screening studies is of great significance, adding both enzyme stability and reuse potentiality of the biocatalytic system in assay merits. In this work, pancreatic lipase was immobilized on 3D-printed PLA microwells for enzyme inhibitor screening. XPS analysis demonstrated the successful modification of the PLA scaffolds. The immobilized enzyme displayed high levels of operational, thermal, and storage stability under the tested conditions. The IC50 values for PPL inhibition were calculated for Orlistat, a model lipase inhibitor, and olive leaf extract, a promising natural compound. This is the first study reporting the use of 3D-printed PLA wells with an immobilized enzyme for inhibitor screening assay.

Poly(lactic acid) (PLA)/germanane (GeH) nanocomposites with antioxidant and antibacterial properties with low GeH content.