Microalgae are a renewable and sustainable source of bioactive compounds, such as essential amino acids, polyunsaturated fatty acids, and antioxidant compounds, that have been documented to have beneficial effects on nutrition and health. Among these natural products, the demand for natural antioxidants, as an alternative to synthetic antioxidants, has increased. The antioxidant activity of microalgae significantly varies between species and depends on growth conditions. In the last decade, microalgae have been explored in livestock animals as feed additives with the aim of improving both animals’ health and performance as well as product quality and the environmental impact of livestock. These findings are highly dependent on the composition of microalgae strain and their amount in the diet. The use of carbohydrate-active enzymes can increase nutrient bioavailability as a consequence of recalcitrant microalgae cell wall degradation, making it a promising strategy for monogastric nutrition for improving livestock productivity. The use of microalgae as an alternative to conventional feedstuffs is becoming increasingly important due to food–feed competition, land degradation, water deprivation, and climate change. However, the cost-effective production and use of microalgae is a major challenge in the near future, and their cultivation technology should be improved by reducing production costs, thus increasing profitability.

In the present study, selected cosmeceutical properties of aqueous extracts from the microalgae strain Trachydiscus minutus were assessed and compared with those obtained using three widely used Chlorella strains (C. vulgaris, C. sorokiniana, and C. minutissima). Among all extracts, T. minutus extracts showed the highest total antioxidant capacity (TAC) and inhibitory potency towards elastase, suggesting potential activity in controlling skin aging. Furthermore, the cytotoxicity, anti-inflammatory activity and UVA protection of T. minutus extract were evaluated employing normal human dermal fibroblasts (NHDF) and human keratinocyte HaCaT cells. The results showed that the T. minutus extract was able to significantly inhibit the transcription of selected marker genes involved in inflammation [interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor alpha (TNFα)]. In addition, treatment of NHDF and HaCaT cells with T. minutus extract ameliorate the UVA-induced cell damage by decreasing the accumulation of reactive oxygen species (ROS). Extracts from T. minutus were formulated into a skin care cream and an aqueous gel. Both formulas exhibited excellent compatibility and stability. Comprehensively, all these results suggest that T. minutus extract displays promising cosmeceutical properties by providing antioxidant, anti-aging, and anti-inflammatory activities, and therefore has potential for cosmeceutical use.

Glutathione transferases (GSTs; EC 2.5.1.18) form a group of multifunctional enzymes that are involved in phase II of the cellular detoxification mechanism and are associated with increased susceptibility to cancer development and resistance to anticancer drugs. The present study aims to evaluate the ligandability of the human GSTM1-1 isoenzyme (hGSTM1-1) using a broad range of structurally diverse pesticides as probes. The results revealed that hGSTM1-1, compared to other classes of GSTs, displays limited ligandability and ligand-binding promiscuity, as revealed by kinetic inhibition studies. Among all tested pesticides, the carbamate insecticide pirimicarb was identified as the strongest inhibitor towards hGSTM1-1. Kinetic inhibition analysis showed that pirimicarb behaved as a mixed-type inhibitor toward glutathione (GSH) and 1-chloro-2,4-dinitrobenzene (CDNB). To shine a light on the restricted hGSTM1-1 ligand-binding promiscuity, the ligand-free crystal structure of hGSTM1-1 was determined by X-ray crystallography at 1.59 Å-resolution. Comparative analysis of ligand-free structure with the available ligand-bound structures allowed for the study of the enzyme’s plasticity and the induced-fit mechanism operated by hGSTM1-1. The results revealed important structural features of the H-site that contribute to xenobiotic-ligand binding and specificity. It was concluded that hGSTM1-1 interacts preferentially with one-ring aromatic compounds that bind at a discrete site which partially overlaps with the xenobiotic substrate binding site (H-site). The results of the study form a basis for the rational design of new drugs targeting hGSTM1-1.

Polyhydroxybutyrate (PHB) depolymerases (PHBds) enable bioplastic degradation into reusable monomers, making them essential for sustainable waste management and circular bioeconomy solutions. In this study, we computationally identified and characterized two new PHBds from Cupriavidus malaysiensis (CmaPHBd) and from Pseudomonas guguanensis (PguPHBd). Sequence analysis revealed that both enzymes are classified as extracellular type I depolymerases, containing a conserved N-terminal catalytic domain (CD) and a C-terminal substrate-binding domain (SBD). Recombinant expression in E. coli enabled purification and biochemical characterization of CmaPHBd and PguPHBd. The results demonstrated that CmaPHBd was most active in acidic conditions (pH 5.0-6.0), while PguPHBd exhibited optimum activity in alkaline conditions (pH 9.5). Differential scanning fluorimetry (DSF) analysis indicated a melting temperature (T_m) of 49.6 °C for CmaPHBd, while PguPHBd exhibited two unfolding transitions at 45.7 °C and 57.1 °C. Initial rate kinetics analysis indicated an allosteric regulation in both enzymes and significant substrate inhibition at high PHB concentrations. Among the two enzymes, CmaPHBd exhibited superior degradation efficiency towards solid PHB films. Furthermore, CmaPHBd displayed promiscuous activity against other solid polyhydroxyalkanoate (PHA) films. A domain-shuffling strategy was employed, to enhance the activity PguPHBd towards solid plastic films, by fusing the SBD of CmaPHBd to the CD of PguPHBd. The engineered variant, showed improved degradation efficiency on PHB and related biopolymers, confirming the critical role of SBD in overcoming the rate-limiting adsorption step towards solid plastic films. These findings provide valuable insights into the structural and functional properties of CmaPHBd and PguPHBd, highlighting their potential application in bioplastic degradation, reusability and biocatalysis.

Background/Objectives: Cryptosporidiosis, caused by Cryptosporidium parvum, is a significant cause of diarrheal disease, particularly affecting young children and immunocompromised individuals. With current treatments offering limited efficacy, there is an urgent need for novel therapeutic targets. Methods: In this study, we report the cloning, expression, and functional characterization of a glutathione transferase (GST) from C. parvum (CpGST). Results: Biocomputing analysis revealed a single gene encoding a cytosolic enzyme with distinct structural features, compared to human cytosolic homologs. Structural modeling indicated a non-canonical thioredoxin fold and a truncated C-terminal domain, suggesting functional divergence. CpGST was expressed in Escherichia coli, and its enzymatic properties were characterized. Although the enzyme displayed a narrow substrate spectrum, it showed a distinct substrate preference, retaining catalytic activity toward the standard GST substrates 1-chloro-2,4-dinitrobenzene (CDNB) and cumene hydroperoxide (CuOOH). Steady-state kinetic analysis revealed limited affinity for both reduced glutathione (GSH) and CDNB. Inhibition analysis identified several polyphenols and synthetic curcumin analogues as potent inhibitors, with IC₅₀ values in the low micromolar range. Kinetic analysis with the most potent inhibitor revealed a mixed-type inhibition mechanism. Conclusions: These findings support the classification of CpGST as a structurally and functionally distinct member of the GST family, likely adapted to the parasite’s physiology and metabolism. The enzyme’s divergence from human GSTs, along with its favorable druggability profile, underscores its potential as a target for anti-cryptosporidial drug development, particularly in strategies aimed at disrupting stress response and detoxification pathways.