This study explores the interaction of saponification products with microbial communities in aerobic and anaerobic sewage sludge from wastewater treatment plants (WWTPs). It focuses on the reutilisation of waste cooking oils into soap and evaluates the biodegradation of these products using microbial respiration activity and biological oxygen demand (BOD) as indicators. Results demonstrate that soaps degrade effectively under both aerobic and anaerobic conditions, with anaerobic degradation contributing to methane production-a valuable biofuel. Importantly, no toxic effects on sludge microorganisms were observed. The research highlights that these saponification products can be fully integrated into the wastewater treatment process without adverse effects on microbial dynamics. Moreover, the economic analysis reveals that biosurfactants derived from used oils can be produced at a cost of approximately 0.12-3.0 EUR/kg, significantly lower than the 1-20 EUR/kg typically spent on chemical coagulants or synthetic surfactants used in WWTPs. These findings support the feasibility of repurposing waste oils into environmentally friendly, cost-effective treatment additives, enhancing microbial performance and promoting circular economy practices in wastewater management.

• Klíčová slova
• edible oil waste, microorganism respiration, sustainability, wastewater treatment efficiency,
• MeSH
• aerobióza MeSH
• anaerobióza MeSH
• Bacteria metabolismus   MeSH
• biodegradace MeSH
• čištění vody * metody   MeSH
• měření biologické spotřeby kyslíku MeSH
• mýdla metabolismus   MeSH
• odpad tekutý - odstraňování * metody   MeSH
• odpadní voda * mikrobiologie   chemie   MeSH
• odpadní vody * mikrobiologie   MeSH
• povrchově aktivní látky metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• mýdla MeSH
• odpadní voda * MeSH
• odpadní vody * MeSH
• povrchově aktivní látky MeSH

For the development of functional edible packaging that will not lead to rejection by the consumer, it is needed to analyze the interactions between ingredients in the packaging matrix. The aim of this study was to develop edible chitosan-based coatings that have been enriched with red grape extracts, zinc, silver, and titanium nanoparticles. The organoleptic properties of the produced edible packaging were described by quantitative descriptive analysis and consumer acceptability was verified by hedonic analysis. By image analysis, color parameters in the CIELab system, opacity, Whiteness and Yellowness Index were described. The microstructure was described by scanning electron microscopy. The hedonic evaluation revealed that the addition of nanometals and their increasing concentration caused a deterioration in sample acceptability. The overall evaluation was higher than 5 in 50% of the samples containing nanometals. The addition of nanometals also caused statistically significant changes in L*, a*, and b* values. The sample transparency generally decreased with the increasing concentration of nanoparticle addition. Scanning electron microscopy showed, that the addition of nanometals does not disrupt the protective function of the packaging. From a sensory point of view, the addition of ZnO nanoparticles in concentrations of 0.05 and 0.2% appeared to be the most favorable of all nanometals.

• Klíčová slova
• CIELab, nanoparticles, packaging, plant extract, scanning electron microscopy, sensory properties,
• Publikační typ
• časopisecké články MeSH

The aim of the research was to produce edible packaging based on chitosan with the addition of various concentrations of extracts of blueberry, red grape and parsley marcs. Packaging was made from extrudate extracts, which were subsequently analyzed by physicochemical methods: zeta-potential, gas barrier properties, thickness, water content, solubility, swelling degree, textural properties, total polyphenol content (TPC), polyphenols by high pressure liquid chromatography (HPLC), antioxidant activity, attenuated total reflectance Fourier-Transform spectroscopy (FTIR), antimicrobial activity and determination of migration of bioactive substances. The results indicate that a higher content of plant extracts have a statistically significant (p < 0.05) influence on properties of experimentally produced edible films. Edible films produced with the highest concentrations of red grapes marc extracts showed the most advantageous properties since antimicrobial activity against E. coli were the highest in this kind of produced film. The physical properties of edible films were also improved by the addition of extracts; gas permeability toward oxygen can be defined as advantageous, as can swelling degree, which decreased with higher concentrations of extracts. The research emphasized the possibility to use plant foodstuffs by-products in the production of edible/biodegradable films, helping in the overall sustainability and eco-friendliness of food/package production.

• Klíčová slova
• FTIR, antimicrobial properties, antioxidant activity, barrier properties,
• Publikační typ
• časopisecké články MeSH