In this research, antimicrobial polysaccharide chitosan was used as a surface coating for packaging material. The aim of our research was to establish an additive formulation of chitosan and antioxidative plant extracts as dispersion of nanoparticles. Chitosan nanoparticles with embedded thyme, rosemary and cinnamon extracts were synthesized, and characterized for this purpose. Two representative, commercially used foils, polypropylene (PP) and polyethylene (PE), previously activated by UV/ozone to improve coating adhesion, were functionalized using chitosan-extracts nanoparticle dispersions. The foils were coated by two layers. A solution of macromolecular chitosan was applied onto foils as a first layer, followed by the deposition of various extracts embedded into chitosan nanoparticles that were attached as an upper layer. Since active packaging must assure bioactive efficiency at the interface with food, it is extremely important to understand the surface characteristics and phenomena of functionalized foils. The physico-chemical analyses of functionalized foils were thus comprised of surface elemental composition, surface charge, wettability, as well as surface morphology. It has been shown that coatings were applied successfully with an elemental composition, surface charge and morphology that should enable coating stability, homogeneity and consequently provide an active concept of the packaging surface in contact with food. Moreover, the wettability of foils was improved in order to minimize the anti-fogging behavior.

Two-layer functional coatings for polyethylene (PE) and polypropylene (PP) films were developed for the active packaging concept. Prior to coating, the polymer films were activated by O₂ and NH₃ plasma to increase their surface free energy and to improve the binding capacity and stability of the coatings. The first layer was prepared from a macromolecular chitosan solution, while the second (upper) layer contained chitosan particles with embedded catechin or pomegranate extract. Functionalized films were analyzed physico-chemically to elemental composition using ATR-FTIR spectroscopy and XPS. Further, oxygen permeability and wettability (Contact Angle) were examined. The antimicrobial properties were analyzed by the standard ISO 22196 method, while the antioxidative properties were determined with an ABTS assay. Functionalized films show excellent antioxidative and antimicrobial efficacy. A huge decrease in oxygen permeability was achieved in addition. Moreover, a desorption experiment was also performed, confirming that the migration profile of a compound from the surfaces was in accordance with the required overall migration limit. All these properties indicate the great potential of the developed active films/foils for end-uses in food packaging.

In this research, antimicrobial polysaccharide chitosan and natural extracts were used as surface coating of a plastic laminate with an integrated whey layer on the inside. The aim was to establish the biodegradable and active concept of packaging laminates. For this purpose, chitosan nanoparticles (CSNPs) with embedded rosemary or cinnamon extracts were synthesised and characterised. Additionally, a whey-based laminate was functionalised: i) chitosan macromolecular solution was applied as first layer and ii) cinnamon or rosemary extracts encapsulated in CSNPs were applied as upper layer (layer wise deposition). Such functionalised whey-based laminate was physicochemically characterized in terms of elemental surface composition, wettability, morphology and oxygen permeability. The antimicrobial activity was tested against Staphylococcus aureus, Escherichia coli, Aspergillus flavus and Penicillium verrucosum. The antioxidant properties were determined using the ABTS assay. It could be shown that after functionalization of the films with the above-mentioned strategy, the wettability was improved. Furthermore, such whey-based laminates still show excellent barrier properties, good antimicrobial activity and a remarkable antioxidative activity. In addition to the improved biodegradability, this type of lamination could also have a positive effect on the shelf-life of products packaged in such structured films.

Polypropylene (PP) and polyethylene (PE) foils, previously activated by ultraviolet (UV)/ozone, were functionalized using chitosan-extract nanoparticle dispersions. A solution of macromolecular chitosan was applied onto foils as a first layer, followed by the deposition of various extracts encapsulated into chitosan nanoparticles, which were attached as an upper layer. Functionalized foils were analyzed from a bioactive point of view, i.e., regarding antimicrobial and antioxidant activity. Desorption kinetics were also studied. Moreover, barrier properties were examined, as the most important parameter influencing antimicrobial and antioxidant activity. Finally, all these properties were correlated with different surface parameters, determined previously, in order to understand if there is any direct correlation between surface elemental composition, surface charge, contact angle, or morphology and a specific bioactive property. It was shown that great bioactive properties were introduced due to the additive effect of antimicrobial chitosan and antioxidative plant extracts. Moreover, oxygen permeability decreased significantly, and the migration of polyphenols and chitosan from the foil surface was below the OML (overall migration limit), which is very important for food industry applications. Furthermore, surface properties of foils influence to some extent the desired bioactivity.

Increasing the use of renewable energy sources is one of the most important goals of energy policies in several countries to build a sustainable energy future. This contribution proposes the synthesis of a biorefinery supply network for a case study of the European Union (EU-27) under several scenarios based on a mathematical programming approach. Several biomass and waste sources, such as grains, waste oils, and lignocellulosics, are proposed to be utilized, and various biofuels including first, second, and third generations are produced such as bioethanol, green gasoline, biodiesel, Fischer Tropsch (FT) diesel, and hydrogen. The aim of this study is to evaluate the capabilities of EU-27 countries to be able to meet the Renewable Energy Directive (RED II) target regarding the share of renewable energy in the transport sector by 2030 in each Member State while not compromising the current production of food. A generic mathematical model has been developed for the multi-period optimization of a biorefinery supply network with the objective of maximizing sustainability profit. The solutions obtained show that biomass and waste are promising raw materials to reach and go beyond the EU’s renewable energy target in the transport sector for the year 2030. However, some countries would need to provide additional subsidies for their companies to achieve at least a non-negative economic performance of biofuel production.

The 5th International Conference on Technologies & Business Models for Circular Economy (TBMCE) was organized by the Faculty of Chemistry and Chemical Engineering, University of Maribor in collaboration with the Strategic Research and Innovation Partnership - Networks for the Transition into Circular Economy (SRIP- Circular Economy) and Chamber of Commerce and Industry of Štajerska. The conference was held in Portorož, Slovenia, at the Grand Hotel Portorož from September 12th to September 14th, 2022. TBMCE 2022 was devoted to presentations of circular economy concepts, technologies and methodologies that contribute to the shift of business entities and society as a whole to a more responsible, circular management of resources. The conference program included panel discussions, plenary and keynote sessions, oral and poster presentations on the following topics: Sustainable energy, Biomass and alternative raw materials, Circular business models, Secondary raw materials and functional materials, ICT in Circular Economy, Processes and technologies. The event was under the patronage of Ministry of Economic Development and Technology. 5. mednarodna konferenca Tehnologije in poslovni modeli za krožno gospodarstvo: Zbornik povzetkov. Fakulteta za kemijo in kemijsko tehnologijo Univerze v Mariboru je v sodelovanju s Strateško razvojno-inovacijskim partnerstvom – Mreže za prehod v krožno gospodarstvo (SRIP – Krožno gospodarstvo) in Štajersko gospodarsko zbornico organizirala 5. mednarodno znanstvenoraziskovalno, strokovno in razvojno konferenco Tehnologije in poslovni modeli za krožno gospodarstvo (Technologies & Business Models for Circular Economy; TBMCE), ki je potekala od 12. do 14. septembra 2022 v Grand hotelu Portorož. TBMCE 2022 je namenjena predstavitvi konceptov krožnega gospodarstva in tehnologij ter metodologij, ki prispevajo k preusmeritvi gospodarskih subjektov in družbe kot celote k bolj odgovornemu, tj. krožnemu ravnanju z viri. Konferenčni program je vključeval panelne diskusije, plenarno in uvodna predavanja, ustna predavanja in predstavitve v obliki posterjev z naslednjih področij: trajnostna energija, biomasa in alternativne surovine, krožni poslovni modeli, sekundarne surovine in funkcionalni materiali, IKT v krožnem gospodarstvu, procesi in tehnologije. Dogodek je potekal pod pokroviteljstvom Ministrstva za gospodarski razvoj in tehnologijo.