Ispitivanje značajnih čimbenika za biorazgradnju polistirena i poli(vinil-klorida) bakterijom Delftia acidovorans

master's thesis

• Title (english): Determination of significant factors for biodegradation of polystyrene and polyvinyl chloride by Delftia acidovorans
• Author: Lucija Ružaj
• Mentor: Dajana Kučić Grgić (mentor)
• Committee member: Dajana Kučić Grgić (predsjednik povjerenstva)
• Committee member: Šime Ukić (član povjerenstva)
• Committee member: Matija Cvetnić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2021-09-20, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Čestice MP-a jedan su od najvećih onečišćivala okoliša današnjice. Brojna istraživanja dokazala su MP-e ima negativan utjecaj na biljni i životinjski svijet, a posljedično i na čovjeka. Odlikuje ih velika čvrstoća, primjenjivost i izdržljivost te unatoč otkriću različitih načina uklanjanja, još uvijek nije otkriven učinkovit način za njihovo potpuno uklanjanje. Jedan od njih je biorazgradnja, to jest, cijepanje polimera na monomore pomoću mikroorganizama. Istraživanja su pokazala da sposobnost biorazgradnje PS-a i PVC-a imaju različite bakterije te se u ovom radu provelo ispitivanje značajnih čimbenika za biorazgradnju PS-a i PVC-a bakterijskim kulturama Bacillus subtilis i Delftia acidovorans. U pokusu je predviđeno 7 čimbenika – pH vrijednost, temperatura, broj okretaja, veličina MP-a, koncentracija MP-a, optička gustoća (OG) i dodatak glukoze, na 2 razine – minimalna i maksimalna vrijednost. Rezultati statističke analize eksperimentalnih podataka pokazuju da biorazgradnji čestica PS-a primjenom bakterije Bacillus subtilis najviše doprinosi optička gustoća (81,72 %) i pH-vrijednost (3,82 %). Značajni čimbenici u biorazgradnji čestica PVC-a bakterijom Bacillus subtilis su optička gustoća koja doprinosi 94,33 % i pH-vrijednost s doprinosom od 3,14 %. Biorazgradnji primjenom bakterije Delftia acidovorans najviše doprinosi temperatura za razgradnju PS-a (41,67 %) i PVC-a (74,31 %) dok ostali faktori doprinose u puno manjem postotku. Dokazano je da korištene bakterijske kulture imaju sposobnost biorazgradnje čestica PS-a i PVC-a, međutim, vrlo je važno primjeniti uvjete u kojima je biorazgradnja najuspješnija.

Abstract (english)

Nowadays, microplastic particles are one of the biggest pollutions and threats to the environment. It has been proven by many scientists that MP particles have negative effects on plants and animals, and therefore on humans. The particles of MP are characterized by exceptional strength, high durability and resistance to external conditions and biodegradation. Although there are numerous studies showing different ways of their degradation, it is almost impossible to degrade them completely. One of the ways is biodegradation, which is the breakdown of polymers into monomers by microorganisms. It has been shown that particles of PS and PVC can be degraded by various bacteria. In this study, Bacillus subtilis and Delftia acidovorans were used for the degradation of PS and PVC particles. Biodegradation was tested on the basis of 7 factors - pH, temperature, number of revolutions per minute, size of MP particles, concentration of MP, optical density (OD) and addition of glucose, at two levels - minimum and maximum. The results of statistical analysis of the experimental results show that OD (81.72%) and pH (3.82%) contribute the most to the degradation of PS particles by Bacillus subtilis. The highest contribution to the degradation of PVC particles by Bacillus subtilis is also made by OD (94.33 %) and pH (3.14 %). On the other hand, the highest factor contributing to the degradation of PS and PVC particles by Delftia acidovorans is temperature with a percentage of 41.67% for PS and 74.31% for PVC. In this study, it was proved that the bacterial strains Bacillus subtilis and Delftia acidovorans have the ability to degrade PS and PVC particles, but it is of great importance to choose the right conditions for the highest efficiency.

• Keywords: mikroplastika; biorazgradnja; PS; PVC; Bacillus subtilis; Delftia acidovorans
• Keywords (english): microplastic; biodegradation; PS; PVC; Bacillus subtilis; Delftia acidovorans
• Language: croatian
• URN:NBN: urn:nbn:hr:149:056799
• 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: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Applied organic chemistry; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra primijenjene kemije (magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-04-14 11:00:04