Nevena Prlainović

The modification of agricultural wastes for improved phosphate removal from wastewater is an innovative approach aimed to address the growing environmental challenges posed by nutrient pollution. As agricultural runoff contributes significantly to the eutrophication of water bodies, the effective removal of phosphorus from wastewater has become a critical necessity for environmental sustainability. This field of study not only explores the repurposing of agricultural residues but also emphasizes their potential as low-cost bio-based sorbents for phosphate remediation, thereby offering a dual benefit of waste reduction and environmental protection. Research has shown that various types of agricultural wastes, when modified through physical and chemical processes, can enhance their ability to capture and retain phosphorus from wastewater. Techniques such as metal loading and biochar production have proven effective, leading to notable advancements in the efficacy of these materials as phosphate adsorbents. Studies have indicated that chemically and thermically modified agricultural wastes can achieve phosphorus removal efficiencies comparable to traditional methods, making them a promising alternative in wastewater treatment applications. Despite the potential benefits, the implementation of modified agricultural wastes also faces several challenges. Issues such as: the economic feasibility of large-scale application, the complexity of modification processes, and concerns about the long-term sustainability of these technologies present significant hurdles. Overall, the modification of agricultural wastes represents a vital intersection of waste management and environmental conservation, promoting a circular bioeconomy while providing practical solutions to the pressing problem of nutrient pollution in aquatic systems.

Over the past three decades, organic reactions catalyzed by lipase have been extensively studied. To overcome the drawbacks of free enzymes and develop new and sustainable biocatalysts, various insoluble forms of lipases were examined. Especially interesting are lipases immobilized on silica nanoparticles (SiNPs) due to their promising unique and advantageous physicochemical properties. Therefore, the present paper presents an overview of different organic functionalization methods of SiNP surfaces to create a more favorable microenvironment for lipase molecules. Given the high commercial value of lipases in biotechnological applications, the second part of this paper highlights the key industrial sectors utilizing these nanobiocatalysts. This review discusses the key industrial applications of silica-based lipase nanobiocatalysts, including biodiesel production, flavor ester synthesis, and pharmaceutical applications such as racemization. Special attention is given to emerging technologies, particularly the use of immobilized lipases in polymer biodegradation and polymerization reactions. These advances have paved the way for innovative solutions, such as self-degrading bioplastics, which hold significant promise for sustainable materials and environmental protection. This comprehensive overview underscores the transformative potential of lipase–SiNP nanobiocatalysts in both industrial and environmental contexts.

The increasing pollution from the textile industry, particularly organic azo dyes, presents a significant environmental challenge, necessitating the development of effective and sustainable treatment methods. This study investigates the adsorption potential of hazelnut shells (raw—RHSs; modified—MHSs) for the removal of organic azo dyes from aqueous solutions. As biomass, hazelnut shells are biodegradable and represent a sustainable alternative to synthetic adsorbents, thereby reducing the ecological footprint. Through a series of batch adsorption experiments, the influence of various parameters, including pH, contact time, concentration, and temperature, on adsorption capacity was examined. Characterization of the hazelnut shells was conducted using optical microscopy and ATR-FTIR, XRF, and XRD spectroscopy, confirming its suitability as a biosorbent. The analyzed isotherms showed that adsorption onto RHSs was best fitted by the Freundlich model, while adsorption onto MHSs was best fitted by the Temkin model. Kinetic studies demonstrated that the adsorption process is well described by the pseudo-second-order model, suggesting that chemical adsorption plays a significant role. The maximal adsorption capacity was 62.11 mg/g for RHSs and 80.65 mg/g for MHSs, highlighting the potential of hazelnut shells as an abundant, low-cost, and eco-friendly adsorbent. Furthermore, recycling studies indicated the feasibility of the adsorbent, underscoring its practical applicability in real scenarios.

Lipase-catalyzed organic reactions have been widely practiced in the past three decades. Especially interesting are insoluble/immobilized forms due to providing a possibility of facile use and recyclability, thus reducing process costs, and making the procedure more environmentally friendly. Carbon-based supports have been extensively exploited for this purpose, because of neutral and biodegradable nature and thermal and chemical stability. Their high specific surface area, characteristic surface morphology and lower mass transfer resistances play a vital role in the performance of the attached enzyme. This review paper presents an overview of the main aspects of lipase immobilized on multi-walled carbon nanotubes (MWCNTs). Moreover, different immobilization strategies to achieve a biocatalyst with improved performances are discussed. Furthermore, as lipases are considered to have high commercial worth for synthesis of valuable organic molecules, the second part of the paper is dedicated to the overview of the most important industrial sectors in which these nanobiocatalysts have been used. In specific, applications in biodiesel production, flavour ester synthesis and racemization are summarize

The esters of substituted 1,4-dihydropyirdines (1,4-DHP) are formed in the reaction of an appropriate aldehyde and ethyl acetoacetate in the presence of concentrated water solution of ammonia. The esters form the amides by the reaction with primary amines. The series of the amides has been synthesized with the aim to analyze their chemical characteristics, antioxidant and antimicrobial activity. The amine used in this research is 2-aminothiazole. The antioxidant activity is analysed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) methods and the antimicrobial activity screening was performed by broth microdilution method, using different microbial strains. The characterization of the obtained amides was done by melting points, FTIR, NMR and elemental analysis. The possibilities for further research was suggested, which could lead to the application of selected compounds.

The quest for sustainable biomaterials with excellent biocompatibility and tailorable properties has put polyhydroxyalkanoates (PHAs) into the research spotlight. However, high production costs and the lack of bioactivity limit their market penetration. To address this, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was combined with a bacterial pigment with strong anticancer activity, prodigiosin (PG), to obtain functionally enhanced PHBV-based biomaterials. The samples were produced in the form of films 115.6–118.8 µm in thickness using the solvent casting method. The effects of PG incorporation on the physical properties (morphology, biopolymer crystallinity and thermal stability) and functionality of the obtained biomaterials were investigated. PG has acted as a nucleating agent, in turn affecting the degree of crystallinity, thermal stability and morphology of the films. All samples with PG had a more organized internal structure and higher melting and degradation temperatures. The calculated degree of crystallinity of the PHBV copolymer was 53%, while the PG1, PG3 and PG3 films had values of 64.0%, 63.9% and 69.2%, respectively. Cytotoxicity studies have shown the excellent anticancer activity of films against HCT116 (colon cancer) cells, thus advancing PHBV biomedical application potential.

The specific objectives of the presented study were related to the optimization of the production process of N-alkyl-, N,N-dialkyl-, and N-cycloalkyl-O-isobutyl thiocarbamate; trial industrial production of N-ethyl-O-isobutyl thiocarbamate; and the evaluation of flotation efficiency of N-ethyl-O-isobutyl thiocarbamate using a real ore sample. The optimization of thiocarbamate syntheses were performed by varying the molar ratio of isobutyl alcohol, carbon disulfide, potassium hydroxide, reaction time, and reaction temperature. In the first step, one-pot reaction took place to produce alkyl xanthate and was followed with chlorination to give alkyl chloroformate (O-alkyl carbonochloridothioate); finally, thiocarbamates were obtained by the reaction with corresponding amines. N-alkyl-O-ethyl thiocarbamate was synthesized as a comparative flotation agent. The structure of the synthesized compounds was confirmed by IR, ¹H and ¹³C NMR, and MS instrumental methods, and the purity was determined by gas chromatographic method and elemental analysis. The optimized methods gave high-purity products in a significant yield that was also confirmed by semi-industrial production of N-ethyl-O-isobutyl thiocarbamate. The optimized thiocarbamate synthesis, without isolation of intermediates, is of great importance from the aspect of green technologies. Flotation efficiency test results, using real copper and zinc ores, showed the highest activity of N-ethyl-O-isobutyl thiocarbamate. The optimal one-pot thiocarbamate synthesis provides a simple procedure with a high conversion degree, and, thus, offers valuable technology applicable at the industrial scale.