Bioremedijacija vode onečišćene mikroplastičnim česticama polistirena primjenom bakterijske kulture Pseudomonas alcaligenes

master's thesis

• Title (english): Bioremediation of water polluted with polystyrene microplastic particles using bacterial culture Pseudomonas alcaligenes
• Author: Marika Puškarić
• Mentor: Dajana Kučić Grgić (mentor)
• Committee member: Dajana Kučić Grgić (predsjednik povjerenstva)
• Committee member: Vesna Ocelić Bulatović (član povjerenstva)
• Committee member: Lidija Furač (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2022-09-26, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Razgradnja pogrešno zbrinutog ili nezbrinutog polimernog otpada u okolišu dugotrajan je proces s neželjenim i zabrinjavajućim produktima. Na taj način, uslijed klimatskih utjecaja, dolazi do slabljenja fizikalnih i kemijskih svojstava plastičnog materijala, ali i njegova propadanja što pak otvara mogućnost migracije zrakom ili vodom do živih organizama. Takve čestice, kojima se još uvijek ne zna točan rizik, a predstavljaju veliku zabrinutost, nazivamo mikroplastika (MP). MP kategoriziramo kao polimerne čestice veličine manje od 5 mm. Glavni fokus do sada bio je na ekotoksikološkim istraživanjima, a sada i na pokušaj dizajna alternativnog sustava za bioremedijaciju glavnih sastavnica okoliša u svrhu zaštite od potencijalnih štetnih učinaka na ekosustave. Cilj ovog rada bio je razgradnja MP-a polistirena (PS) i poli(vinil-klorida) (PVC) pomoću bakterijske kulture Pseudomonas alcaligenes u vodenom okolišu i evidentiranje potencijalnih štetnih učinaka nepoznatih metabolita koji pritom mogu nastati. Primijenjen je puni faktorski plan (eng. Full factorial design) za postavljanje pokusa s tri čimbenika na tri razine. Glavni ispitivani čimbenici u pokusu s PS-om bili su veličina čestica, broj okretaja i optička gustoća (OG), a s PVC-om pH-vrijednost, koncentracija MP-e i OG. Pokus se provodio tijekom 30 dana, a uzorci za analizu izuzimani su u 0., 3., 7., 14., 21. i 30. danu. U navedenim danima pratila se koncentracija organskog i anorganskog ugljika, OG, CFU i nastajanje nusprodukata procesa HPLC-MS analizom. Analiza promjena u strukturi čestica PS-a i PVC-a nakon pokusa provedena je FTIR-ATR spektroskopijom, a toksičnost filtrata određena je bakterijom V. fischeri. Svim navedenim analizama potvrđeno je da u procesu uistinu dolazi do promjena u strukturi plastike što indicira da se ona biorazgrađuje. Analizom varijance (ANOVA) potvrđeno je da je model značajan u oba pokusa, a da su optimalni uvjeti za provođenje pokusa s PS-om: broj okretaja od 180 o/min, veličina MP-a 203 μm i OG 0,27. U pokusu s PVC-om idealni su uvjeti pH 7, γMP 50 mg/L i OG 0,3.

Abstract (english)

Decomposition of incorrectly disposed or unmanaged polymer waste in the environment is a long-term process with unwanted and worrying products. In this way, climatic influences enable weakening of physical and chemical properties of plastic material but also its decay, which in turn opens the possibility of migration by air or water to living organisms. Such particles, whose exact risk is still unknown and of great concern, are called microplastics (MP). They are categorized as polymer particles smaller than 5 mm in size. The main focus so far has been on ecotoxicological research, but now also on trying to design an alternative system for bioremediation of the main components of the environment in order to protect the ecosystems against potential adverse effects. The aim of this study was to biodegrade polystyrene and polyvinyl chloride MP by use of Pseudomonas alcaligenes bacterial culture in an aquatic environment and to record the potential adverse effects of unknown metabolites that may occur. A Full factorial design was applied to set up a three-factor experiment on three levels. The main factors in the PS experiment were particle size, number of revolutions, and optical density (OG) and with PVC there were pH value, MP concentration and optical density (OG). The experiment was conducted for 30 days and samples were taken on the 0., 3., 7., 14., 21. and 30. day. In aformentioned days we monitored the concentration of organic and inorganic carbon, OG, CFU and by-products formation with HPLC-MS analysis. Analysis of changes in the PS and PVC particle structure after the experiment was carried out by FTIR-ATR spectroscopy and the toxicity of the filtrate was determined by use of bacteria V. fischeri. All the aforementioned analyzes confirmed that the process actually causes changes in the structure of the plastic, which indicates that it biodegrades. Analysis of variance (ANOVA) confirmed that the model is significant in both experiments and that the optimal conditions for conducting experiments with PS are: number of revolutions of 180 rpm, MP size 203 μm and OG 0,27. In the experiment with PVC, the ideal conditions are pH 7, γMP 50 mg/L and OG 0,3.

• Keywords: mikroplastika; Pseudomonas alcaligenes; bioremedijacija; puni faktorski plan; polistiren; poli(vinil-klorid)
• Keywords (english): microplastics; Pseudomonas alcaligenes; bioremediation; Full factorial design; polystyrene; polyvinyl chloride
• Language: croatian
• URN:NBN: urn:nbn:hr:149:182833
• Project: Number: IP-2019-04-9661; Title: Primjena naprednih tehnologija obrade voda za uklanjanje mikroplastike; Title: Advanced Water Treatment Technologies for Microplastics Removal; Acronym: AdWaTMiR; Leader: Tomislav Bolanča; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Environmental Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka ekoinženjerstva (magistar/magistra inženjer/inženjerka ekoinženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2024-06-01
• Created on: 2023-03-23 13:09:04