Primjena kvasca u biorazgradnji mikročestica polistirena i poli(vinil-klorida)

master's thesis

• Title (english): Biodegradation of polystyrene and poly(vinyl chloride) microparticles by yeast
• Author: Petra Krajnik
• Mentor: Šime Ukić (mentor)
• Committee member: Šime Ukić (predsjednik povjerenstva)
• Committee member: Matija Cvetnić (član povjerenstva)
• Committee member: Dajana Kučić Grgić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2023-09-18, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Interdisciplinary Technical Sciences

Abstract

Masovna proizvodnja, stalna uporaba i nepropisno zbrinjavanje plastičnih proizvoda rezultiraju sve znatnijim onečišćenjem okoliša. Veće plastične čestice postupno se razgrađuju u okolišu na manje čestice od kojih se one sitnije od 5 mm nazivaju mikroplastikom (MP). Iako glavnina komercijalne plastike još uvijek otpada na polimere koji su postojani u okolišu i nisu skloni biorazgradnji, identificiran je niz mikrobnih sojeva s potencijalom biorazgradnje MP-a u prirodnom okolišu. Mikroorganizmi, kao što su bakterije, gljivice ili alge, nalaze se posvuda u prirodi i sposobni su prilagoditi se različitim uvjetima okoliša, pa nije čudno što neki od njih mogu razgrađivati i plastične polimere. U ovom radu ispitala se biorazgradnja predtretiranih mikročestica polistirena i poli(vinil-klorida) primjenom okolišno prisutnog kvasca Candida parapsilosis s ciljem određivanja optimalnih uvjeta procesa biorazgradnje. MP se karakterizirala FTIR-ATR spektroskopijom, a tijekom eksperimenta određivao se broj živih stanica kvasca (CFU) koji se zatim koristio kao odziv pri određivanju optimalnih uvjeta biorazgradnje. Eksperimenti su provedeni prema potpunom faktorskom dizajnu pri čemu se ispitao utjecaj pH, optičke gustoće i broj okretaja tresilice; svaki od ovih faktora ispitan je na tri razine. Uz određivanje CFU, provedene su i TOC i HPLC/MS analize. Na kraju, ispitana je toksičnost profiltrirane otopine nakon procesa biorazgradnje primjenom bakterije
Vibrio fischeri.

Abstract (english)

Mass production, constant use, and improper disposal of plastic products are leading to ever-increasing environmental pollution. Larger plastic particles gradually break down in the environment into smaller particles, of which those smaller than 5 mm are called microplastics (MP). The main commercial plastics are stable in the environment and cannot be biodegraded, but a number of microbial strains have been identified that have the potential to biodegrade MP in the natural environment. Microorganisms such as bacteria, fungi or algae are found everywhere in nature and are able to adapt to different environmental conditions, so it is not surprising that some of them can also degrade plastic polymers. In this work, the biodegradation of pretreated microparticles of polystyrene and poly(vinyl chloride) was investigated using the environmentally occurring yeast Candida parapsilosis to determine the optimal conditions for the biodegradation process. MP was characterized by FTIR-ATR spectroscopy, and the number of live yeast cells (CFU) was determined during the experiment, which was then used as a response in determining the optimal biodegradation conditions. The experiments were performed according to a full factorial experimental design in which the influence of pH, optical density, and the rpm of the shaker were studied; each of these factors was investigated in three stages. In addition to the determination of CFU, TOC and HPLC/MS analyzes were also performed. Finally, the toxicity of the filtered solution after the biodegradation process was tested with the bacterium Vibrio fischeri.

• Keywords: mikroplastika; polistiren; poli(vinil-klorid); biorazgradnja; Candida parapsilosis
• Keywords (english): microplastics; polystyrene; poly(vinyl-chloride); biodegradation; Candida parapsilosis
• Language: croatian
• URN:NBN: urn:nbn:hr:149:999538
• 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: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-09-22 08:46:34