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Dear colleagues, we are extremely honoured to present to you the Proceedings of the international conference 19th Ružička Days, which was successfully held on September 21–23, 2022, in Vukovar, Croatia, in the hometown town of our famous Croatian scientist and first Nobel laureate, professor Leopold (Lavoslav) Ružička. The main goals of the Conference were to promote excellence, originality and innovation of interdisciplinary scientific research as well as the practical application of the obtained results through collaboration with industry, emphasizing thus the recognizable slogan of the Ružička Days conference: "Today Science – Tomorrow Industry". In addition, the Conference gave the opportunity for meetings, exchanging the ideas, opinions, experiences and cooperation among participants from different working surroundings. It is also important to point out that since 2008, within the international conference Ružička Days, Meeting of Young Chemists has also been held, where high school students, with the help of their mentors, present papers in the field of chemistry, with the aim to direct students and young people to the technical and natural sciences, especially chemistry. In its seventh issue (2011, 2013, 2015, 2017, 2019, 2021) the Proceedings publishes scientific and professional full papers of high quality in the following sections: Chemical analysis and synthesis (10), Chemical and biochemical engineering (3), Food technology and biotechnology (4), Chemistry in agriculture and forestry (1), Environmental protection (9) and 8th Meeting of Young Chemists (3). Full-length papers were subjected to an international review procedure done by eminent experts from the corresponding fields, to whom we express our gratitude, but they were not subjected to linguistic proofreading. On behalf of the Scientific and Organizing Committee of the 19th Ružička Days we cordially thank all the authors, reviewers, participants, lecturers, organizers, especially the international organizers EuCheMS and EHEDG, auspices and sponsors, and all the others who, in any way, supported the Conference and contributed to the preparation of the Proceedings, especially to our highly skilled and committed associates, who have put a lot of effort in the preparation of these Proceedings. At the very end, special thanks to our young, future scientists and their mentors who are faithful participants of the Meeting of Young Chemists of the Ružička Days conference. Enjoy the extremely interesting scientific and professional papers contained in these Proceedings, until the next 20th jubilee of Ružička Days in 2024! We are looking forward to meeting you again in Vukovar! Yours sincerely, Chief Editors Jurislav Babić Vesna Ocelić Bulatović Dajana Kučić Grgić

Uslijed antropogenog djelovanja, ksenobiotici dospijevaju u okoliš. Ksenobiotici, među koje se ubrajaju farmaceutici, antibiotici, otrovi te pesticidi, su tvari koje su biološki aktivne, a zaostaju u okolišu u visokim koncentracijama s obzirom na njihovu jaku postojanost i bioakumulaciju. Prema tome, potrebno je istraživati njihov utjecaj na organizme u okolišu. U ovome je radu istraživana ekotoksičnost dvaju ksenobiotika, diklofenaka i pantoprazola, na četiri testna organizma: morskoj bakteriji Vibrio fischeri, bakteriji Pseudomonas putida, mikroalgi roda Chlorella, te kvascu Saccharomyces cerevisiae. Ispitivan je ekotoksični utjecaj svakog pojedinog navedenog kseonobiotika, ali i njihove smjese u volumnim omjerima 1:1, 2:1 i 1:2. Za navedeno je proveden test ekotoksičnosti s V. fischeri tijekom 30 min izloženosti uz praćenje smanjenja bioluminiscencije bakterije. Ukupan broj živih stanica bakterija (CFU) P. putida te mikroalgi Chlorella sp., pratio se tijekom 3 dana provedbe pokusa u svrhu uočavanja ekotoksičnog utjecaja na rast navedenih mikroorganizama. Tijekom istog vremena izloženosti, provodio se i pokus sa S. cerevisiae u kojem se pratio volumen nastalog CO2, odnosno volumen istisnute tekućine. Rezultati promjene inhibicije u odnosu na ispitivane koncentracije diklofenaka i pantoprazola su prikazani karakterističnom krivuljom doza-odgovor, a kao najosjetljiviji testni organizmi pokazali su se S. cerevisiae te V. fischeri.

Mikrobiološka istraživanja podrazumijevaju uzgoj mikroorganizama na hranjivoj podlozi u Petrijevim zdjelicama uz primjenu u poljoprivredne, prehrambene te medicinske svrhe. Izrasle kolonije se prebrojavaju u svrhu određivanja ukupnog broja živih stanica bakterija (Colony Forming Unit, CFU). Određivanje CFU može biti dugotrajno, pogotovo u slučaju gustog uzorka, prilikom kojeg se može lako pogriješiti. U svrhu ubrzavanja provedbe ove analize te značajne uštede vremena mikrobiolozima, postojeća se analiza pokušava unaprijediti uz računalnu tehnologiju. Prvi uređaj koji se koristio za automatsko brojanje kolonija korišten je 1957. godine. Slika Petrijeve zdjelice se skenirala na CRT zaslonu pomoću fotomultiplikatora, a obrada digitalizirane slike se vršila pomoću računala. Stoga, glavni dijelovi automatskog brojača su kamera i računalo s odgovarajućim softverom za obradu slike. Novija inačica koja je ispitivana čini Sony cyber shot kamera uz Biowizard softver za analizu slike. U usporedbi s ručnim brojanjem kolonija i drugim komercijalnim softverima, dobiveni su bolji rezultati o parametrima kolonija uz kraće vrijeme analize primjenom Biowizard-a. Nekoliko automatiziranih sustava za brojanje kolonija je komercijalno dostupno (poput ProtoCOL, Whitley aCOLyte, AID BacSpot), ali nemaju široku upotrebu zbog njihove visoke cijene. Stoga je potrebno usmjeriti daljnja istraživanja u razvoj i povećanje preciznosti automatiziranog sustava uz dostupnost za laboratorijske upotrebe.

Pored životinja i biljaka, mikroorganizmi predstavljaju najraznovrsniju grupu živih bića na Zemlji. Oni su najstariji stanovnici Zemlje i predhodnici su svih živih organizama. Tom svijetu pripadaju bakterije, gljive, alge, protozoe, virusi i drugi organizmi različiti po svojoj građi i životnim aktivnostima. Većina mikroorganizama je malih dimenzija. Na površini tijela čovjeka, životinja, biljaka i drugih predmeta koji nas okružuju, mnoge vrste mikroorganizama su redovni stanovnici. Njihovo prisustvo se bilježi svuda osim u zatvorenim biološkim sistemima kao što su krvotok i fiziološki aktivna tkiva životinja i biljaka. Moglo bi se reći da su rasprostranjeni u svim životnim sredinama i klimatskim zonama, u zraku, vodi i tlu. U sklopu ove radionice promatrat ćemo mikroorganizme iz dječje perspektive. Prvi dio radionice će se bazirati na upoznavanju i razlikovanju mikroorganizama koji nas okružuju i dati će odgovore na mnoga pitanja poput, kakve su boje, gdje rastu, da li se kreću, kako ih uzgojiti, kakve su boje podloge na kojima ih uzgajamo, da li ih možemo obojiti da ih lakše prepoznamo? Da li su svi mikroorganizmi loši? Kako možemo dokazati prisutnost mikroorganizama na rukama? Kako možemo spriječiti širenje infekcija? Djeca će imati priliku mikroskopirati mikroorganizme koji rastu na pokvarenom voću, povrću, u šumi, na dlanu i dr. Upoznati će se s osnovnim priborom koji se koristi u mikrobiološkom laboratoriju. U drugom djelu radionice djeca će naučiti pravilno odvajati otpad i kako oni mogu doprinijeti zaštiti okoliša. Što više reći? Posjetite nas i upoznajte misteriozne, male i nevidljive oku bića.

Danas plastiku primjenjujemo svakodnevno i život bez nje je nezamisliv. Među najkorištenijim plastikama su polietilen (PE), polipropilen (PP), poli(vinil-klorid) (PVC) i poli(etilen-tereftalat) (PET)[1]. Posljedica široke primjene plastika je njihova akumulacija u okolišu što može izazivati negativne utjecaje po okoliš, ali i po ljudsko zdravlje. Zbog toga se traže novi načini uklanjanja plastičnog otpada iz okoliša, a jedan način je i biorazgradnja. Biorazgradnja se odvija primjenom mikroorganizama koji su sposobni enzimima razgraditi polimerni lanac plastičnih materijala[1]. U ovome se radu istraživala biorazgradnja PVC mikroplastike (MP) pomoću gram-pozitivne bakterijske kulture Bacillus subtilis. Pokus je proveden prema Full factorial dizajnu ispitujući tri čimbenika na 3 razine: pH (6, 7 i 8), broj okretaja rotacijske tresilice (100, 150 i 200 o/min) i optička gustoća (OG) bakterijske suspenzije (0, 1, 0, 3 i 0, 5). Cilj je bio odrediti optimalne uvjete biorazradnje PVC MP uz karakterizaciju tako provedenog pokusa. Pokus je trajao mjesec dana tijekom kojih se određivao ukupan broj živih stanica bakterija (CFU) te koncentracija ukupnog ugljika (TC), organskog ugljika (TOC) i anorganskog ugljika (TIC). Nakon provedenog pokusa biorazgradnje, iz vodene faze su odvojene čestice MP-a. Potom su čestice PVC MP okarakterizirane FTIR-ATR spektroskopijom, dok se LC-MS analiza primijenila za ispitivanje mogućih otpuštenih aditiva s PVC MP u vodenu fazu. Na kraju je izmjerena i ekotoksičnost vodene faze provedbom testa ekotoksičnosti primjenom morske bakterije Vibrio fischeri, kako bi se utvrdilo nastaju li štetni razgradni produkti biorazgradnjom PVC-a. Dobiveni rezultati pokusa su obrađeni pomoću Design Expert programa uz statističku analizu (ANOVA) podatka. Dakle, optimalni uvjeti biorazgradnje PVC MP primjenom Bacillus subtilis su: pH = 7, 74, broj okretaja = 200 o/min uz OG = 0, 5. Za te uvjete je dobivena EC50 vrijednost od 16, 28 %. Također, trend pada TOC vrijednosti upućuje da je došlo do razlaganje organske molekule polimernog lanca PVC-a.

Masovna proizvodnja i primjena, kao i neadekvatno zbrinjavanje plastike, doveli su do njezinog nakupljanja u okolišu. Plastika raznim procesima prelazi u mikroplastiku (MP), kojom se smatraju čestice plastike veličinom manje od 5 mm. Zbog potencijalnog toksičnog učinka, MP je postala središtem brojnih ekotoksikoloških ispitivanja. Stoga su trenutne potrebe zaustaviti njezino dospijevanje u okolišu, te pronaći najefikasnije načine za uklanjanje MP-a iz okoliša. Jedan od njih je proces biorazgradnje koji je poželjan i ekološki prihvatljiv proces no uz ograničenu učinkovitost u prirodnim uvjetima. Cilj ovog rada je bio ispitati optimalne uvjete za proces biorazgradnje MP-a primjenom bakterijske kulture Delftia acidovorans kombinirajući tri čimbenika: pH vrijednost, optičku gustoću (OG) i broj okretaja rotacijske tresilice uz konstantnu veličinu čestica i koncentraciju MP-a prema punom faktorskom planu. Korištene mikroplastične čestice polistirena (PS) izlagane su tijekom 30 dana bakteriji Delftia acidovorans, gdje je praćen broj živih stanica bakterijske kulture (CFU) i koncentracija ukupnog, organskog i anorganskog ugljika. Korištena je metoda LC-MS za praćenje potencijalno otpuštenih aditiva s površina čestica PS-a, a ATR-FTIR spektroskopija za potvrdu strukture i biorazgradnje PS-a. Ispitana je ekotoksičnost MP-e PS-a primjenom morske bakterije Vibrio fischeri uz određivanje vrijednosti EC20 i EC50. Prema rezultatima pokusa, određeni su optimalni uvjeti biorazgradnje PS primjenom Delftia acidovorans pri pH-vrijednosti 8, OG = 0, 5 i broju okretaja rotacijske tresilice 172, 12 o/min.

Mikroskopski oblici života nalaze se u velikom broju u zraku koji udišemo, u vodama i tlu, u hrani, na površini našeg tijela. Mikroorganizmi se golim okom ne vide, no njima je ispunjen svijet. Iako vidljivi samo mikroskopom, odigrali su ključnu ulogu u povijesti života na Zemlji.

Za potrebe javne ustanove, ispitani su različiti omjeri mješavine mulja iz primarnog taložnika i ostalih dostupnih supstrata za proces kompostiranja (laboratorijska razina). Na temelju dobivenih rezultata predložena je najbolja mješavina za kompostiranje u biostabilizatoru K16.

Packaging waste, especially that made from non- biodegradable polymers, has become a significant part of municipal solid waste, leading to growing environmental problems. To address this problem, much attention has been paid in recent years to the development of biodegradable polymers from renewable resources, which is also encouraged by global environmental awareness. The demand for biodegradable and renewable materials for packaging applications has increased tremendously. Degradation of biodegradable polymers disposed in landfills is often initiated by microorganisms via enzymatic catalytic processes. The end products of biodegraded polymers typically include CO2, CH4, water, biomass, and other natural materials that are important for potential greenhouse gas accounting benefits and other environmental impacts. In the food industry, food safety is of the greatest importance. However, the development of biodegradable, compostable packaging materials good for the product and the planet are becoming the ultimate goal, of the food and packaging industries. Therefore, the real challenge for the research community is how to balance these requirements. Development of an innovative, biodegradable packaging materials, need to provide good barrier properties to preserve food safety and quality within the shelf life, if not extend it. This paper provides information on the performance of biodegradable polymers, focusing on food packaging. It provides an overview of the classification of biodegradable polymers, focusing mainly on biodegradable polymers from biomass products and green-based antimicrobial packaging materials.

Dear colleagues, we are extremely honoured to present to you the Proceedings of the international conference 19 th Ružička Days, which was successfully held on September 21–23, 2022, in Vukovar, Croatia, in the hometown town of our famous Croatian scientist and first Nobel laureate, professor Leopold (Lavoslav) Ružička. The main goals of the Conference were to promote excellence, originality and innovation of interdisciplinary scientific research as well as the practical application of the obtained results through collaboration with industry, emphasizing thus the recognizable slogan of the Ružička Days conference: "Today Science – Tomorrow Industry". In addition, the Conference gave the opportunity for meetings, exchanging the ideas, opinions, experiences and cooperation among participants from different working surroundings. It is also important to point out that since 2008, within the international conference Ružička Days, Meeting of Young Chemists has also been held, where high school students, with the help of their mentors, present papers in the field of chemistry, with the aim to direct students and young people to the technical and natural sciences, especially chemistry. In its seventh issue (2011, 2013, 2015, 2017, 2019, 2021) the Proceedings publishes scientific and professional full papers of high quality in the following sections: Chemical analysis and synthesis (10), Chemical and biochemical engineering (3), Food technology and biotechnology (4), Chemistry in agriculture and forestry (1), Environmental protection (9) and 8th Meeting of Young Chemists (3). Full-length papers were subjected to an international review procedure done by eminent experts from the corresponding fields, to whom we express our gratitude, but they were not subjected to linguistic proofreading. On behalf of the Scientific and Organizing Committee of the 19th Ružička Days we cordially thank all the authors, reviewers, participants, lecturers, organizers, especially the international organizers EuCheMS and EHEDG, auspices and sponsors, and all the others who, in any way, supported the Conference and contributed to the preparation of the Proceedings, especially to our highly skilled and committed associates, who have put a lot of effort in the preparation of these Proceedings. At the very end, special thanks to our young, future scientists and their mentors who are faithful participants of the Meeting of Young Chemists of the Ružička Days conference. Enjoy the extremely interesting scientific and professional papers contained in these Proceedings, until the next 20th jubilee of Ružička Days in 2024! We are looking forward to meeting you again in Vukovar! Yours sincerely, Chief Editors Jurislav Babić Vesna Ocelić Bulatović Dajana Kučić Grgić

Tackling hazardous substances pollution in the Danube River Basin by Measuring, Modelling-based Management and Capacity building (Danube Hazard m3c) is an Interreg project co-funded by the European Union (ERDF, IPA, ENI). 14 countries of the Danube basin are involved in the project, including Croatia. The main objective of the project is to establish a coherent and comprehensive screening of the water status of the Danube basin. According to the EU Water Framework Directive, pollution by hazardous substances is an important water quality problem in the Danube River Basin that needs to be addressed. This also applies to non-EU member states, which have committed to pursue similar goals under the International Commission for the Protection of the Danube River. The project is based on three elements of water governance: measuring, modelling, and management. Part of the project involves collecting and cataloguing available data on measurements of hazardous substances in the basin and analyzing existing rules and regulations that each country participating in the project adheres to. Conclusions are presented based on analyses of the main aspects of policies related to the management of hazardous substances in water, mainly in the following areas: national legislative frameworks, monitoring of hazardous substances in surface water, management of hazardous substances in groundwater, point source emitters, diffuse polluters, fees, analytical methods, databases and registers, and inventories of emissions of priority substances.

More than eight million tons of plastic end up in the oceans every year - a serious threat to the environment and health. Whether packaging or toys, mulch films or cars, plastics based on petrochemicals are ubiquitous - demand is rising and with it the mountains of waste. The enormous negative environmental impact of disposing of so- called "single-use" plastics is driving the market to seek new solutions, and requiring initiatives that encourage science, industry and government agencies to respond more quickly to the introduction and implementation of new materials. Bioplastics, based on natural materials such as starch or synthetic biomaterials like polylactic acid, are produced partially or entirely from renewable sources and are often marketed as a 'green' alternative. However, this does not necessarily mean that they are compostable or biodegradable, as biodegradability does not depend on the initial components of a material, but rather on its chemical structure and specific environmental properties. Numerous abiotic and biotic factors influence the possibility and rate of degradation, and environmental conditions must be suitable for biodegradation to take place. Many bio-based plastic products biodegrade only in specific environments or in industrial composting facilities, but not in the natural environment. For example, a laboratory experiment showed that the mass of PLA decreased by only 2.5% after 600 days under simulated marine environmental conditions. Similarly, studies indicate that PLA bottles and bags biodegrade by only 3% and 4%, respectively, in 180 days in the marine environment. The issue of degradation time is extremely important and needs to be properly considered when setting criteria and standards for 'biodegradable' plastics. The maximum allowable degradation times for biodegradable plastics should be short enough to ensure that they do not have harmful effects on biota and/or the environment.

As part of the professional cooperation, the ecotoxicity of certain samples on the water system was determined. For this purpose, three standardized ecotoxicity tests were used.

Hazardous substances (HS) pollution is a significant water management issue in the Danube River Basin (DRB) that needs basin-wide pollution assessments and harmonized abatement measures through transboundary cooperation. Danube countries – under the auspices of the International Commission for the Protection of the Danube River – have made significant efforts to tackle HS pollution by conducting targeted monitoring campaigns, applying basin scale water quality models and implementing various control measures. Yet, chemicals are still found in the aquatic environment having ubiquitous persistent, bioaccumulative and toxic features and leading to failing good status of surface water bodies. Thus, further steps need to be taken towards a more “toxic-free” DRB, fully in line with the ambitions of the EU Green Deal. Despite the substantial progress achieved in controlling HS pollution in the DRB, further efforts are needed in the future to sustainably manage the problem. Narrowing the information gap related to HS pollution is a key aspect, the state-of-the-art knowledge regarding monitoring and chemical emissions needs to be massively improved. Moreover, the water management sector has to adapt its policies and measures to reflect to the latest EU requirements and to establish an enabling regulatory framework that can support and control the implementation of these policies. In addition, in some Danube countries, substantial lack of institutional capacity, unclear responsibilities and insufficient intersectoral dialogue hinder the establishment of an efficient management. Furthermore, the pressure of climate change impacts on water quality management is rapidly growing, both high intensity rainfall events and drought periods may cause adverse effects if they are not counteracted by adaptation measures.

Microplastics (MP) are polymer particles smaller than 5 mm and are divided into primary and secondary [1]. Primary microplastics are formed during industrial production. When it enters the environment, it breaks down through physical, chemical, and biological processes into smaller particles that form secondary microplastics. The most commonly produced and used polymer types are polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET) and polystyrene (PS). Microplastics pose a problem because they persist in the environment for long periods of time, are insoluble in water, are difficult to decompose, have a complex polymer composition, can transfer hydrophobic pollutants adsorbed to microplastics, have effects on aquatic organisms that can bioaccumulate, enter the food chain, and affect human health [2]. In this context, the biodegradation of secondary MP PS by the bacterium Bacillus subtilis which was isolated from compost was studied. The experiment was conducted according to the Full Factorial design. Three factors (size of PS particles, optical density of bacterial suspension, and speed of rotary shaker) were studied at three levels (minimum, average, and maximum). During the 30-day experiment, the number of live bacterial cells and the concentration of total carbon were monitored. At the end of the experiment, the PS particles were analyzed by FTIR spectroscopy. Optimal conditions were observed at average value of PS size (300-500 µm) and optical density (0.3), as well as maximum value of speed of rotary shaker (200 rpm). According to the obtained results, Bacillus subtilis is the suitable choice for biodegradation of PS.

Cancer is a complex, prevalent and fatal disease that notably affects almost every tissue in the human body, and many anticancer drugs are currently being used clinically for the treatment of several malignancies. [1] However, solid tumors such as breast cancer, resist most of the clinically-available anticancer agents probably due to gene mutations or epigenetic modifications during the course of therapy that affect the uptake, metabolism of efflux of drugs from cancer cells. Benzoxazoles derivatives show significant pharmacophoric behavior with diverse range of biological activities including antitumor activity. [2, 3] In this paper, we present the synthesis of novel 1, 2, 3-triazolyl benzoxazole derivatives by using click reaction in deep eutectic solvents (DES). The key precursors of Schiff bases were synthesized by ultrasound irradiation, and subsequent cyclization reaction with NaCN gave the corresponding 2-arlybenzoxazoles which are furthermore converted to O-propargylated benzoxazole derivatives by microwave assisted alkylation reactions. 1, 2, 3-triazolyl benzoxazole derivatives were prepared by click-reaction of O-propargylated benzoxazole derivatives with corresponding azides in DES (ChCl/glycerol). All synthesized compounds were evaluated against Gram-positive and Gram-negative bacterial strains as well as malignant tumor cell lines. 2-(4-(2-morpholinoethoxy)phenyl)benzoxazole showed the most pronounced activity against non-small-cell lung cancer cell lines (NCI-H460, IC50=0.4 µM).

U okviru stručne suradnje određena je ekotoksičnost i biorazgradljivost određenih uzoraka - aditiva.

Zahvat vode nalazi se u zasunskoj komori HE Zakučac i to po jedan zahvat DN 700 mm na tlačnim cjevovodima 1 i 3. U nastavku se cjevovodi DN 700 mm spajaju u čelični cjevovod DN 800 mm, kojim se voda gravitacijski dovodi do pogona obrade, na filtriranje, dezinfekciju i nakon obrade u distribuciju.U filtarskom sloju voda ostavlja preostale nečistoće, prolazeći kroz sloj fino zrnatog kvarcnog pijeska, koji svojom kapilarnom silom i velikom apsorpcijskom sposobnošću zadržava, u postojećim međuprostorijama između pojedinih zrna, preostale mehaničke i koloidne otopljene materije, veliki dio algi i bakterija. Proces filtracije odvija se uslijed toga sve sporije i poslije izvjesnog vremena više nije u stanju propustiti normalne količine vode.

U sklopu stručne suradnje za potrebe javne ustanove napravljena je detaljna fizikalno-kemijska i mikrobiološka karakterizacija mulja iz primarnog taložnika, strukturnog materijala i supstrata sličnog kompostu dobivenog procesom kompostiranja.

Plastika je nezamjenljivi materijal današnjice i ne postoji područje života bez nje. Važna je na područjima pakiranja, transporta, građevinarstva, medicine i elektronike. Iako su plastični materijali visoke kvalitete, zabrinjavajuće je može li se ovim plastičnim materijalom u našem društvu pravilno upravljati. Dok je plastika postala visoko cijenjena zbog svoje dugotrajne funkcionalne upotrebe, nedavno su se pojavila mnoga gledišta o opasnostima za okoliš povezanim s plastikom i energetskim krizama. Čestice plastike i druge onečišćujuće tvari, poput aditiva, nalaze se u našem okolišu i prehrambenom lancu te predstavljaju prijetnju ljudskom zdravlju, a i pridonose klimatskim promjenama. Razvoj biorazgradive plastike usmjeren je na stvaranje održivijeg i zelenijeg svijeta s manjim utjecajem na okoliš. Biorazgradiva plastika također može imati svojstva slična tradicionalnoj plastici, a istovremeno donosi dodatne prednosti zbog svog minimalnog utjecaja na okoliš, primjerice smanjena je emisija ugljikovog(IV) dioksida, te se može razgraditi procesom kompostiranja. Potražnja za ekonomičnim, ekološki prihvatljivim materijalima raste u cilju smanjenja otpada kroz bolje upravljanje resursima.

U sklopu stručne suradnje za potrebe javne ustanove, na temelju dobivenih rezultata dana je preporuka za vođenje procesa kompostiranja u biostabilizatoru K16.

As part of the 4th ZORH, the journal Chemistry in Industry was presented and instructions for writing papers were given.

Benzothiazole represents an important class of compounds with a wide spectrum of biological activities such as antimicrobial, antitumor and antituberculostatic activity and possesses special significance in the field of medicinal chemistry [1, 2]. Hydrazones show strong therapeutic activity due to the presence of N ̶ N i C=N bonds [3] and well-known drug with the hydrazone group is Levosimendan, which is used in the treatment of acute decompensated congestive heart failure. This paper describes the solvent-free mechanochemical synthesis of targeted hydrazone- bridged benzothiazole derivatives. 6-substituted 2-hydrazinylbenzo[d]thiazoles were prepared by reaction of 2-amino benzothiazole with hydrazine hydrate in the presence of ethylene glycol and hydrochloric acid. Mechanochemical reaction of 2- hydrazinylbenzothiazole with an appropriate aromatic aldehydes gave the target 2-substituted benzothiazole derivatives bridged by hydrazone unit. Structural characterization of all newly prepared benzothiazole derivatives was performed by 1H and 13C-NMR spectroscopy. Furthermore, using the 2D-NOESY technique, it was confirmed that the prepared compounds were obtained in the form of the E-isomer. Of all evaluated compounds against bacterial cells of Escherichia coli, Enterococcus Faecalis, Klebsiella Pneumonia, Pseudomonas aeruginosa, Staphylococcus aureus, the most pronounced antibacterial activity on bacterial strain Pseudomonas aeruginosa was shown by the 6- chloro-benzothiazole derivative with N, N-diethyl substituent (MIC = 4 mg/L).

Bioplastics are not just one single material They comprise of a whole family of materials with different properties and applications. According to European Bioplastics, a plastic material is defined as a bioplastic if it is either biobased, biodegradable, or features both properties.Biobased is the material or product (partly) derived from biomass (plants)e.g. corn, sugarcane, or cellulose. Biodegradable polymers are mostly produced from plant-based materials PLA is obtained from FERMENTED STARCH, which is itself obtained from corn, cassava, sugar cane or sugar beet. TPS is produced by HEATING STARCH from plant materials with water and mixing with plasticisers. PHAs are distinct in that they’re extracted from BACTERIA, which produce it by fermenting sugar or lipids obtained from waste or plant-based feedstocks.

Plastics have excellent application properties and therefore are used in various fields of human life. The annual production of plastics is increasing, as is the amount of plastic waste. Plastics are ubiquitous in the environment, where they break down into smaller particles called microplastics (MP) due to physical impact, UV radiation, and other environmental factors. Recently, ecotoxicological studies for MP have revealed potential adverse effects of MP on aquatic organisms. Therefore, it is necessary to investigate possible solutions to remove MP from the environment. In this context, the biodegradation of PS and PVC MP was studied using different microorganisms isolated from the environment enriched with MP. The experiments were divided into two parts: preliminary experiments and main experiments. The preliminary experiments on biodegradation of MP were performed with 5 bacteria (Bacillus cereus, Bacillus subtilis, Pseudomonas alcaligenes, Delftia acidovorans and Bacillus licheniformis) and 5 yeasts (Saccharomyces cerevisiae, Rhodotorula glutinis, Geotrichum candidum, Trichosporon sp. and Candida parapsilosis). During 30 days, the changes in the total number of bacteria and yeasts (CFU) were monitored. In addition, the particles of MP were analyzed by FTIR spectroscopy. Based on the results of the preliminary experiments, the most effective bacterium and yeast were selected for the main biodegradation experiment. Therefore, the main experiments with Delftia acidovorans and Candida parapsilosis were conducted according to a full factorial experimental design with 3 parameters at 3 levels to determine the optimal process conditions. The parameters studied were pH-value, agitation speed, and optical density of the bacteria/yeast suspension. In this case, the size of MP (25-100 μm), the concentration of MP (500 mg/L), and the temperature (25 ± 0.2 °C) were constant. In addition, the main objective of this work was to determine the most efficient bacterium and yeast for biodegradation of MP and the optimal conditions to achieve the highest efficiency of the biodegradation process.