magistrsko delo
Žiga Nolde Drev (Author), Miha Humar (Reviewer), Romana Marinšek-Logar (Mentor)

Abstract

Odpadna ovčja volna zaradi počasne in energijsko zahtevne razgradnje v Evropi in po svetu postaja vedno večji okoljevarstven problem. Počasna razgradnja je posledica visoke vsebnosti keratina v ovčji volni, ki ga stabilizira velika količina disulfidnih vezi. Keratin je energetsko bogata beljakovina, ki je zaradi težavne razgradnje redko izkoriščena kot substrat za proizvodnjo bioplina. V nalogi smo raziskovali vpliv mikrobne in encimske razgradnje ovčje volne, ki smo jo nato uporabili kot substrat v testih biometanskega potenciala. Ovčjo volno smo izpostavili različnim mešanicam šestih keratinolitičnih mikroorganizmov (A. reticulisporus, S. coelicoflavus, B. mycoides, B. weidmanii, B. subtilis in B. altitunidis) oziroma njihovih grobih encimskih ekstraktov. Teste BMP smo izvedli v litrskih serumskih steklenicah pri anaerobnih in mezofilnih pogojih (37 °C), trajali so različno dolgo, glede na proizvodnjo bioplina. Spremljali smo volumen nastalega bioplina in njegovo sestavo, pH, vsebnost in sestavo kratkoverižnih maščobnih kislin. Rezultati poskusov so pokazali, da je imelo največji pozitiven vpliv na proizvodnjo bioplina avtoklaviranje, predobdelava je izplen nekoliko zmanjšala. Specifična proizvodnja bioplina je bila v primerjavi z encimsko nekoliko večja pri mikrobni predobdelavi. Največjo specifično proizvodnjo bioplina in metana smo izmerili pri poskusu BMP 3, v katerem smo kot substrat uporabili dvakrat avtoklavirano ovčjo volno. Pri vzorcih, kjer je bila ovčja volna predobdelana z mešanico vseh šestih mikroorganizmov oziroma encimskih ekstraktov, je bil izplen bioplina in metana večji kot pri tistih, kjer je bila ovčja volna predobdelana z mešanicami manjšega števila mikroorganizmov.

Keywords

bioplin;ovčja volna;mikroorganizmi;predobdelava;razgradnja keratina;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [Ž. Nolde Drev]
UDC: 606:62:677.31:628.336.6(043.2)
COBISS: 210584579 Link will open in a new window
Views: 41
Downloads: 8
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Other data

Secondary language: English
Secondary title: Pretreatment of sheep wool with keratinolytic microorganisms for biogas production
Secondary abstract: Due to its slow and energy-demanding decomposition, waste sheep wool is becoming an ever-increasing environmental problem in Europe and around the world. The slow degradation is due to the high content of keratin in sheep wool, which is stabilized by a large amount of disulfide bonds. Keratin is an energy-rich protein that, due to its difficult breakdown, is rarely exploited as substrate for biogas production. In the assignment, we investigated the influence of microbial and enzymatic degradation of sheep's wool, which was then used as a substrate in biomethane potential tests. Sheep wool was exposed to different mixtures of six keratinolytic microorganisms (A. reticulisporus, S. coelicoflavus, B. mycoides, B. weidmanii, B. subtilis and B. altitunidis) or their rough enzyme extracts. The BMP tests were carried out in liter serum bottles under anaerobic and mesophilic conditions (37 °C), and they lasted for different lengths of time, depending on the biogas production. We monitored the volume of biogas produced and its composition, pH, content and composition of volatile fatty acids. The results of the experiments showed that autoclaving had the greatest positive impact on biogas production, while pretreatment slightly reduced the yield. The specific production of biogas was slightly higher in microbial pretreatment compared to enzymatic. The highest specific production of biogas and methane was measured in experiment BMP 3, in which twice autoclaved sheep's wool was used as substrate. In samples where sheep wool was pre-treated with a mixture of all six microorganisms or enzyme extracts, the production of biogas and methane was greater than in those where sheep wool was pre-treated with mixtures of a smaller number of microorganisms.
Secondary keywords: biogas;sheep wool;microorganisms;pretreatment;keratin degradation;
Type (COBISS): Master's thesis/paper
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Študij biotehnologije
Pages: 1 spletni vir (1 datoteka PDF (IX, 61 str.))
ID: 25186366