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Melanins are pigments widely distributed in microbial, plant, and animal kingdoms. Their UV–visible light shielding capacity, metal chelation ability, antioxidant, and antimicrobial properties make these pigments suitable for different industrial applications like in cosmetic and bioremediation fields. The actual manufacturing process relies on the extraction from animal tissues like the ink of Sepia officinalis and/or on synthetic chemical procedures. Streptomycetes might be the ideal candidates for the development of biotechnological processes of melanin production due to their ability to produce pigments as secondary metabolites, extracellularly released. Here, a new strain of Streptomyces nigra, capable of efficiently producing eumelanin, was isolated from soil samples in Messina, Sicily, Italy, and characterized first by 16S rRNA analysis and then by whole genome sequencing, with a complete gene clusters analysis. The strain ability of growing and producing melanin was tested on four media, including newly formulated ones, and by also optimizing temperature and pH conditions of growth, a melanin production of 2.45 ± 0.01 g/L was reached. The pigment, once produced under the optimal conditions, was purified and characterized by UV–visible, FT-IR, NMR, and EPR spectroscopy, revealing an eumelanin-like structure. Key points • A new Streptomyces nigra strain, MT6, was isolated and identified • A new formulated medium boosted melanin production up to 2.45 g/L • The extracellular pigment was characterized as eumelanin

Biosurfactants, amphiphilic metabolites produced by bacteria and yeasts, fulfill a variety of functions in microbial life. They exhibit a well-recognized multifunctionality, spanning from the reduction in surface tension to specific biological activities, including antimicrobial, antiviral, anti-inflammatory, and anticancer effects. These compounds have the potential to serve as environmentally friendly alternatives to synthetic surfactants in industrial formulations, where they could act as emulsifiers and wetting agents. The exploitation of their full potentiality could be a significant added value. Biosurfactants are often cited as effective antioxidants. However, experimental evidence for their antioxidant activity/capacity is sparse. To shed light on the subject, in this review we collect and critically examine all the available literature data for each of the major classes of microbial biosurfactants: rhamnolipids, mannosylerythritol lipids, sophorolipids, and lipopeptides. Despite the variability arising from the diverse composition and polydispersity of the samples analyzed, along with the variety of testing methodologies, the findings consistently indicate a moderate-to-strong antioxidant capacity. Several hypotheses are advanced about the molecular mechanisms behind this action; however, further studies are needed to gain a molecular understanding. This knowledge would fully define the biological roles of biosurfactants and is a prerequisite for the development of innovative formulations based on the valorization of their antioxidant properties.

Increasing biodiesel production poses a significant challenge in managing its primary byproduct, bioglycerol. Advancements in production techniques have markedly enhanced bioglycerol potential applications across various sectors, including as cosolvent in industrial formulations. In the context of eco-sustainable formulation design, this study addresses the self-aggregation of rhamnolipids, biosurfactants with a wide range of physico-chemical and biological activities, in bioglycerol aqueous mixtures, studied by integrating surface tension and NMR self-diffusion measurements. Preliminary analysis of the properties of water-bioglycerol mixtures indicates that bioglycerol impurities (mainly potassium acetate) have only a small effect on surface tension and no discernible effect on bulk properties such as density, viscosity and refractive index. The aggregation of rhamnolipids is unaffected by bioglycerol at concentrations up to 40-50 wt%. At higher cosolvent levels, the cmc increases and the micelle dimension micellar size decreases, an indirect effect of the decreasing polarity of the medium. These results provide the basic knowledge to promote the exploration of rhamnolipids and bioglycerol as valuable ingredients in formulations for various applications.Increasing biodiesel production poses a significant challenge in managing its primary byproduct, bioglycerol. Advancements in production techniques have markedly enhanced bioglycerol potential applications across various sectors, including as cosolvent in industrial formulations. In the context of eco-sustainable formulation design, this study addresses the self-aggregation of rhamnolipids, biosurfactants with a wide range of physico-chemical and biological activities, in bioglycerol aqueous mixtures, studied by integrating surface tension and NMR self-diffusion measurements. Preliminary analysis of the properties of water-bioglycerol mixtures indicates that bioglycerol impurities (mainly potassium acetate) have only a small effect on surface tension and no discernible effect on bulk properties such as density, viscosity and refractive index. The aggregation of rhamnolipids is unaffected by bioglycerol at concentrations up to 40-50 wt%. At higher cosolvent levels, the cmc increases and the micelle dimension micellar size decreases, an indirect effect of the decreasing polarity of the medium. These results provide the basic knowledge to promote the exploration of rhamnolipids and bioglycerol as valuable ingredients in formulations for various applications.

Increasing biodiesel production poses a significant challenge in managing its primary byproduct, bioglycerol. Advancements in production techniques have markedly enhanced bioglycerol potential applications across various sectors, including as cosolvent in industrial formulations. In the context of ecosustainable formulation design, this study addresses the self‐aggregation of rhamnolipids, biosurfactants with a wide range of physicochemical and biological activities, in bioglycerol aqueous mixtures, studied by integrating surface tension and NMR self‐diffusion measurements. Preliminary analysis of the properties of water–bioglycerol mixtures indicates that bioglycerol impurities (mainly potassium acetate) have only a small effect on surface tension and no discernible effect on bulk properties such as density, viscosity, and refractive index. The aggregation of rhamnolipids is unaffected by bioglycerol at concentrations up to 40–50 wt%. At higher cosolvent levels, the cmc increases and the micellar size decreases, an indirect effect of the decreasing polarity of the medium. These results provide the basic knowledge to promote the exploration of rhamnolipids and bioglycerol as valuable ingredients in formulations for various applications. Bioglycerol, the primary byproduct of biodiesel production, has the potential to be valorized as a cosolvent in industrial formulations. Surface tension and self‐diffusion data reveal that rhamnolipid self‐aggregation in water is poorly affected by the addition of bioglycerol up to very high concentrations. These results demonstrate that biosurfactants and bioglycerol are suitable ingredients in ecofriendly product design.

Pericardial patches are currently used as reconstructive material in cardiac surgery for surgical treatment of cardiac septal defects. Autologous pericardial patches, either treated with glutaraldehyde or not, can be used as an alternative to synthetic materials or xenograft in congenital septal defects repair. The availability of an allogenic decellularized pericardium could reduce complication during and after surgery and could be a valid alternative. Decellularization of allogenic tissues aims at reducing the immunogenic reaction that might trigger inflammation and tissue calcification over time. The ideal graft for congenital heart disease repair should be biocompatible, mechanically resistant, non-immunogenic, and should have the ability to growth with the patients. The aim of the present study is the evaluation of the efficacy of a new decellularization protocol of homologous pericardium, even after cryopreservation. The technique has proven to be suitable as a tissue bank procedure and highly successful in the removal of cells and nucleic acids content, but also in the preservation of collagen and biomechanical properties of the human pericardium.