Primjena punog faktorskog plana i metode odzivnih površina pri ispitivanju biorazgradnje polistirena bakterijskom kulturom Delftia acidovorans

master's thesis

• Title (english): Application of the Full Factorial Plan and Response Surface Methodology in the study of biodegradation of polystyrene by bacterial culture Delftia acidovorans
• Author: Katarina Zovko
• 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: 2023-09-29, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Širom svijeta na godišnjoj razini odbace se velike količine plastičnog otpada u okoliš. Jedan od velikih problema je jednokratna plastika i nerazvijeni sustavi za gospodarenje otpadom koji su doveli do gomilanja plastike. Jednom odbačena, plastika može dugi niz godina biti prisutna u okolišu. Pod utjecajem raznih vremenskih i vanjskih uvjeta razgrađuje se na manje čestice poznate kao mikroplastika. Osim toga, mikroplastika se proizvodi s namjerom dodavanja u razne kozmetičke proizvode i proizvode za osobnu njegu. Polistiren je jedna od najčešće korištenih vrsta plastike, pa shodno tome i često pronađen u okolišu. Utjecaj MP-a na organizme i ljudsko zdravlje nije još dovoljno istražen, ali činjenica da je sveprisutna i pronađena i u najudaljenijim mjestima na zemlji izazvala je veliku pozornost i zabrinutost.
K tome doprinosi velika specifična površina sposobna vezivati razne onečišćujuće tvari iz okoliša kao i razne patogene. Zbog toga se sve više provode razni testovi ekotoksičnosti na širokom broju organizama. Osim upoznavanja sa svim mogućim posljedicama izloženosti
MP-u, važno je razviti učinkovite načine njezinog uklanjanja iz okoliša. Posao je izazovan jer zbog svoje male veličine MP uspješno prolazi kroz razne sustave za filtraciju. Procesi biorazgradnje MP-a su obećavajuće zelene metode koje je potrebno razviti i prilagoditi određenim vrstama plastike i mikrobne zajednice. Kod ispitivanja MP-a za dobivanje cjelokupnih informacija važno je koristiti i prikladne metode karakterizacije. U radu je ispitana biorazgradnja MP čestica PS-a bakterijskom kulturom Delftia acidovorans prema punom faktorskom planu. Ispitani su optimalni uvjeti za proces biorazgradnje; pH–vrijednost, broj okretaja rotacijske tresilice i optička gustoća stanice bakterije. Pokus je trajao 30 dana a tijekom tog perioda određivane su vrijednosti ukupnog, organskog i anorganskog ugljika, te broj živih bakterijskih stanica. Potencijalno otpušteni aditivi analizirani su LC/MS metodom, a promjene u strukturi na FTIR_ATR. Ispitana je i ekotoksičnost filtrata primjenom morske bakterije Vibrio fischeri. Rezultati su pokazali da je došlo do određene biorazgradnje MP-a. Dobiveni optimalni uvjeti su pH–vrijednost (8), OG (0,5) i broj okretaja rotacijske tresilice od 172,12 rpm.

Abstract (english)

All over the world, large amounts of plastic waste are thrown into the environment every year. One of the problems is single-use plastic and underdeveloped waste management systems that have led to the accumulation of plastic. Once discarded, plastic can be present in the environment for many years. Under the influence of various weather and external conditions, it breaks down into smaller particles known as microplastics. In addition, microplastics are produced with the intention of being added to various cosmetic and personal care products. Polystyrene is one of the most commonly used types of plastic, and therefore often found in the environment. The influence of MP on the organism and human health has not yet been sufficiently investigated, but the fact that it is ubiquitous and found even in the most remote places on earth has caused great attention and concern. A large specific surface capable of binding various pollutants from the environment as well as various pathogens contributes to this. For this reason, various ecotoxicity tests are increasingly carried out on a wide number of organisms. In addition to becoming familiar with all the possible consequences of exposure to MP, it is important to develop effective ways of removing it from the environment. The work is challenging because due to its small size, MP successfully passes through various filtration systems. MP biodegradation processes are promising green methods that need to be developed and adapted to specific types of plastics and microbial communities. When testing MP, it is important to use appropriate characterization methods to obtain complete information. In this paper, the biodegradation of MP particles of PS by the bacterial culture Delftia acidovorans was examined according to the full factorial plan. The optimal conditions for the biodegradation process were tested; pH-value, the number of revolutions of the rotary shaker and the optical density of a bacterial cell. The experiment lasted 30 days, and during this period the values of total, organic and inorganic carbon, and the number of living bacterial cells were determined. Potentially released additives were analyzed by LC/MS method, and changes in structure by FTIR_ATR. The ecotoxicity of the filtrate was also tested using the marine bacterium Vibrio fischeri. The results showed that there was a certain biodegradation of MP. The obtained optimal conditions are pH-value (8), OG (0.5) and the number of revolutions of the rotary shaker of 172.12 rpm.

• Keywords: mikroplastika; biorazgradnja; optimalni uvjeti; polistiren; bakterijska kultura Delftia acidovorans
• Keywords (english): microplastics; biodegradation; optimal conditions; polystyrene; bacterial culture Delftia acidovorans
• Language: croatian
• URN:NBN: urn:nbn:hr:149:374593
• 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: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra inženjer/inženjerka kemijskog inženjerstva (sveučilišni/a magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2024-01-01
• Created on: 2023-11-24 12:47:29