Izolacija i karakterizacija ksilana iz otpadne poljoprivredne liganocelulozne mase

undergraduate thesis

• Title (english): Isolation and characterisation of xylan from lignocellulosic agriculture waste
• Author: Ines Ćosić
• Mentor: Anita Šalić (mentor)
• Committee member: Anita Šalić (predsjednik povjerenstva)
• Committee member: Bruno Zelić (član povjerenstva)
• Committee member: Dajana Kučić Grgić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2022-09-12, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Lignocelulozna biomasa predstavlja jeftin i obnovljiv izvor sirovine za dobivanje različitih visokovrijednih spojeva. Jedan od tih spojeva je ksilan koji se koristi u proizvodnji alkohola, ksiloze, ksilitola i ksilooligosaharida. Kako bi se omogućila ekstrakcija željenih komponenti prisutnih u lignoceluloznoj biomasi, biomasu je potrebno podvrgnuti različitim postupcima pripreme koji se u pravilu sastoje od nekoliko stupnjeva. Svrha ovoga rada je ekstrakcija i karakterizacija ksilana iz sječke bukve kako bi se ispitao potencijal ove sirovine za daljnju proizvodnju ksilana. Sječka bukve prvo je podvrgnuta ekstrakciji etanolom kako bi se uklonili svi spojevi koje je moguće otopiti u etanolu kao što su nestrukturni ugljikohidrati poput polilola, glukoze, fruktoze, saharoze i škroba. U sljedećem stupnju provedena je delignifikacija u svrhu uklanjanja lignina. Nakon delignifikacije provedena je alkalna ekstrakcija kalijevim hidroksidom koncentracije 2 mol/L i 4 mol/L u trajanju 2 h i 4 h kako bi se izdvojila hemiceluloza iz holoceluloze. Nakon alkalne ekstrakcije, izdvojena je topljiva i netopljiva frakcija hemiceluloze koja je nakon dijalize, u zadnjem stupnju podvrgnuta kiselinskoj hidrolizi. U svrhu određivanja monomernog sastava dobivenih hidrolizata, uzorci su analizirani primjenom kapljevinske kromatografije visoke djelotvornosti (HPLC). Analizom je pokazano da su u uzorcima prisutni šećeri: celobioza, glukoza, ksiloza, arabinoza te kiseline: glukuronska, octena, mravlja i levulinska. Od navedenih komponentni, glavne komponente hemicelulozne frakcije su glukoza i ksiloza, a najveći prinos ksilana odnosno ksiloze dobiven je u uzorku topljive hemicelulozne frakcije koja je podvrgnuta alkalnoj ekstrakciji s 4 mol/L KOH u trajanju od 4 h.

Abstract (english)

Lignocellulosic biomass is a cheap and renewable raw material for the extraction of various high-value compounds. One of those compounds is xylan, which is used to produce alcohol, xylose, xylitol, and xylooligosaccharides. In order to extract the desired components from the lignocellulosic biomass, the biomass has to be subjected to various pretreatment methods in several stages. The purpose of this work is to extract and characterize of xylan from beechwood chips to investigate the potential of this feedstock for further xylan production. Beechwood chips were first subjected to ethanol extraction to remove ethanol soluble substances such as non-structural carbohydrates (polyols, glucose, fructose, sucrose and starch). In the next step, delignification was performed to remove lignin. After delignification, alkaline extraction was performed with potassium hydroxide at concentrations of 2 mol/L and 4 mol/L for 2 h and 4 h, respectively, to separate the hemicellulose from the holocellulose. After alkaline extraction, the soluble and insoluble fractions of hemicellulose were separated and finally subjected to acid hydrolysis followed by dialysis. To determine the monomer composition of the hydrolysate, the samples were analyzed by high-performance liquid chromatography (HPLC). Analysis of the samples revealed that the following sugars were present: cellobiose, glucose, xylose, arabinose, and the following acids: glucuronic acid, acetic acid, formic and levulinic acid. Of the listed components, the main constituents of the hemicellulose fraction are glucose and xylose. The highest yields of xylan or xylose were obtained in the soluble hemicellulose fraction that was subjected to alkaline extraction with 4 mol/L KOH for 4 h.

• Keywords: lignocelulozna biomasa; hemiceluloza; ksilan; sječka bukve; kiselinska hidroliza
• Keywords (english): lignocellulosic biomass; hemicellulose; xylan; beechwood chips; acid hydrolysis
• Language: croatian
• URN:NBN: urn:nbn:hr:149:399203
• Project: Number: KK.01.1.1.04.0107; Title: Biokonverzija lignoceluloznog materijala u visokovrijednu hranu za životinje; Title: Bioconversion of lignocellulosic material into high-value animal feed; Acronym: Bio4Feed; Leader: Mirela Planinić; Jurisdiction: Croatia; Funder: EC; Funding stream: EFRR
• Study programme: Title: Environmental Engineering - Undergraduate study; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka ekoinženjerstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka ekoinženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2023-02-22 12:22:18