Assessment of the Biodegradability and Compostability of Finished Leathers: Analysis Using Spectroscopy and Thermal Methods.

In this study, the biodegradation properties of leather treated with various finishing chemicals were evaluated in order to enhance the sustainability of leather processing. We applied advanced analytical techniques, including FT-IR, thermogravimetric analysis (TGA), and solid-state NMR spectroscopy. Leather samples treated with different polymers, resins, bio-based materials, and traditional finishing agents were subjected to a composting process under controlled conditions to measure their biodegradability. The findings revealed that bio-based polyurethane finishes and acrylic wax exhibited biodegradability, while traditional chemical finishes like isocyanate and nitrocellulose lacquer showed moderate biodegradation levels. The results indicated significant differences in the biodegradation rates and the impact on plant germination and growth. Some materials, such as black pigment, nitrocellulose lacquer and wax, were beneficial for plant growth, while others, such as polyurethane materials, had adverse effects. These results support the use of eco-friendly finishes to reduce the environmental footprint of leather production. Overall, this study underscores the importance of selecting sustainable finishing chemicals to promote eco-friendly leather-manufacturing practices.

Selective Isolation and Identification of Microorganisms with Dual Capabilities: Leather Biodegradation and Heavy Metal Resistance for Industrial Applications.

Tanning, crucial for leather production, relies heavily on chromium yet poses risks due to chromium's oxidative conversion, leading to significant wastewater and solid waste generation. Physico-chemical methods are typically used for heavy metal removal, but they have drawbacks, prompting interest in eco-friendly biological remediation techniques like biosorption, bioaccumulation, and biotransformation. The EU Directive (2018/850) mandates alternatives to landfilling or incineration for industrial textile waste management, highlighting the importance of environmentally conscious practices for leather products' end-of-life management, with composting being the most researched and viable option. This study aimed to isolate microorganisms from tannery wastewater and identify those responsible for different types of tanned leather biodegradation. Bacterial shifts during leather biodegradation were observed using a leather biodegradation assay (ISO 20136) with tannery and municipal wastewater as the inoculum. Over 10,000 bacterial species were identified in all analysed samples, with 7 bacterial strains isolated from tannery wastewaters. Identification of bacterial genera like Acinetobacter, Brevundimonas, and Mycolicibacterium provides insights into potential microbial candidates for enhancing leather biodegradability, wastewater treatment, and heavy metal bioremediation in industrial applications.

Geodermatophilus brasiliensis sp. nov., isolated from Brazilian soil.

A Gram-reaction-positive bacterial isolate, designated Tü 6233(T), with rudimentary, coral-pink vegetative mycelium that formed neither aerial mycelium nor spores, was isolated from a Brazilian soil sample. Chemotaxonomic and molecular characteristics of the isolate matched those described for members of the genus Geodermatophilus. Cell-wall hydrolysates contained meso-diaminopimelic acid as the diagnostic diamino acid and galactose as the diagnostic sugar. The major fatty acids were iso-C(16 : 0), iso-C(15 : 0) and C(17 : 1)ω8c and the predominant menaquinone was MK-9(H4). The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol, an unknown glycophospholipid and an unknown phospholipid. The DNA G+C content of the strain was 75.4 mol%. The 16S rRNA gene sequence identity with members of the genus Geodermatophilus was 94.2-98.7%. Based on phenotypic, chemotaxonomic and phylogenetic data, strain Tü 6233(T) is proposed to represent a novel species, Geodermatophilus brasiliensis sp. nov., with the type strain Tü 6233(T) ( = DSM 44526(T) = CECT 8402(T)).

The macromolecule with antimicrobial activity synthesized by Pseudoalteromonas luteoviolacea strains is an L-amino acid oxidase.

Two purple pigmented bacterial strains, CPMOR-1 and CPMOR-2, have been newly isolated from the Mediterranean Sea. 16S RNA sequencing and phenotypic characteristics indicate that they belong to the species Pseudoalteromonas luteoviolacea. The synthesis of macromolecules with antimicrobial activity is a capacity described in many strains of this species although the nature of those macromolecules has not been reported up to now. The search for antimicrobial compounds in the two new strains described in this work shows that they synthesize a macromolecule with antimicrobial activity that can be inhibited by catalase, as it had been described in the type strain P. luteoviolacea NCIMB 1893(T). This work elucidates the nature of such macromolecule as a novel L-amino acid oxidase (LAO) with broad substrate specificity. The enzyme is most active with Met, Gln, Leu, Phe, Glu, and Trp. In growth media containing those amino acids, the hydrogen peroxide generated by the reaction catalyzed by the LAO mediates its antimicrobial activity.

A genomic screening approach to the structure-guided identification of drug candidates from natural sources.

The potential of actinomycetes to produce natural products has been exploited for decades. Recent genomic sequence analyses have revealed a previously unrecognized biosynthetic potential and diversity. In order to rationally exploit this potential, we have developed a sequence-guided genetic screening strategy. In this "genome mining" approach, genes that encode tailoring enzymes from natural product biosyntheses pathways serve as indicator genes for the identification of strains that have the genetic potential to produce natural products of interest. We chose halogenases, which are known to be involved in the synthesis of halometabolites as representative examples. From PCR screening of 550 randomly selected actinomycetes strains, we identified 103 novel putative halogenase genes. A phylogenetic analysis of the corresponding putative halogenases, and the determination of their sequential context with mass spectrometric analysis of cultures filtrates revealed a distinct correlation between the sequence and secondary metabolite class of the halometabolite. The described screening strategy allows rapid access to novel natural products with predetermined structural properties.

Highlighting the role of the chlorine substituents in the glycopeptide antibiotic balhimycin for chiral recognition in capillary electrophoresis.

The vancomycin-type glycopeptide antibiotic balhimycin (I) and its dehaloanalogue dechlorobalhimycin (III), which is characterized by the total substitution of the two chlorine atoms of I by hydrogen, were employed as chiral selectors for the enantioresolution of 11 racemic dansyl amino acids and six 2-arylpropionic acid nonsteroidal anti-inflammatory racemic drugs by CE. The observed enantioresolution capability of I for all test analytes is clearly higher than that observed for III. This result suggests that chlorine substituents of I played a major role in the enantioresolution of these test analytes. A dimerization-based mechanism is proposed in order to explain this phenomenon. The two chlorine substituents of each monomer, which mutually penetrate into the cavity of the adjacent molecule of the dimer, are assumed to promote dimerization and as a consequence also enantioresolution.