Izolacija keratina iz odpadne biomase z alkalno hidrolizo

magistrsko delo

Klemen Gradišnik (Avtor), Mojca Škerget (Mentor), Maja Čolnik (Komentor), Mojca Poberžnik (Komentor)

Povzetek

Keratin je fibrilarna strukturna beljakovina, ki jo najdemo v različnih telesnih tkivih živali in ljudi. Ta tkiva vključujejo volno, perje, lase, nohte, kljun, luske itd. V zadnjih nekaj letih je keratin zaradi svojih ugodnih kemijsko-fizikalnih lastnosti vzbudil veliko zanimanja na področju biomedicine, farmacije (npr. tkivno inženirstvo) in kozmetike. Nekatere vire keratina je mogoče pridobiti praktično brezplačno, saj mnogi predstavljajo odpadno biomaso ali ostanke v različnih vrstah industrije. Dober primer sta mesna in perutninska industrija, kjer se po vsem svetu proizvedejo velike količine volne in odpadnega perja. Po statističnih podatkih ameriške organizacije za prehrano in kmetijstvo (FAO) je svetovna proizvodnja mesa leta 2018 dosegla kar 342 milijonov ton. To pomeni, da je bila proizvedena tudi zelo velika količina odpadne biomase, bogate s keratinom. Ob prikladnosti nizke cene teh s keratinom bogatih virov z njihovo ponovno uporabo koristimo tudi okolju, saj bi sicer te odpadne proizvode sežgali (kar bi povečalo vsebnost ekvivalentov CO2 v ozračju), zakopali ali odložili na odlagališčih. V okviru magistrske naloge smo izvedli izolacijo keratina z alkalno hidrolizo iz odpadne ovčje volne in perutninskega perja. Kot alkalni medij smo uporabili vodno raztopino NaOH različnih koncentracij (30 mg/ml, 40 mg/ml in 50 mg/ml). Poskusi so bili izvedeni pri različnih reakcijskih časih (1 h, 2 h in 3 h) in obratovalnih temperaturah (50 °C, 65 °C in 80 °C). Nadalje smo raziskali vpliv teh treh vhodnih spremenljivk na molekulsko maso keratina in izkoristek izolacije z metodo odzivnih površin (Box-Behnken). Po alkalni hidrolizi je bil reakcijski produkt bistra in oranžna kapljevina. V mešanici po reakciji je bila še zmeraj prisotna majhna količina nerazgrajenega začetnega materiala, zlasti pri nizkih temperaturah (50 °C) in nizkih koncentracijah NaOH (aq) (30 mg/ml). Izkoristek izolacije je bil relativno nizek in se je gibal med 41,68 % in 66,69 % v primeru volne ter med 38,94 % in 55,20 % v primeru perja. Najvišji izkoristek izolacije iz volne (66,69 %) je bil dosežen pri 50 °C, 3 h in 40 mg/ml, najvišji izkoristek izolacije iz perja (55,20 %) pa pri 50 °C, 2 h in 50 mg/ml. Molekulske mase produktov (keratina) smo določili s pomočjo SDS-PAGE elektroforeze. V večini primerov so bile molekulske mase enakomerno porazdeljene po celotnem pasu od 4,6 kDa do 315 kDa, vendar je bila prevladujoča od 8 kDa do 40 kDa. Ugotovili smo, da višja temperatura (80 °C) in višja koncentracija NaOH (aq) (50 mg/ml) zmanjšata molekulsko maso keratina v vzorcih. Vsi vzorci iz volne in perja so pokazali relativno nizko antioksidativno aktivnost (največ 22,19 %) in negativen zeta-potencial. Opravili smo tudi meritve velikosti delcev in konduktance vzorcev kot tudi analizo s FTIR spektrofotometrom. Rezultati tega dela kažejo, da sta volna in perje odličen vir keratinskih izolatov ter da alkalna hidroliza preučevane odpadne biomase predstavlja dober način prispevanja k čistemu okolju in krožnemu gospodarstvu.

Ključne besede

keratin;odpadna biomasa;alkalna hidroliza;volna;perje;beljakovine;magistrske naloge;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2023
Tipologija:	2.09 - Magistrsko delo
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[K. Gradišnik]
UDK:	66.094.941.094.7:675.08(043.2)
COBISS:	171955715
Št. ogledov:	87
Št. prenosov:	8
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Isolation of keratin from waste biomass using alkaline hydrolysis
Sekundarni povzetek:	Keratin is a fibrillar structural protein found in various body tissues of animals and humans. These tissues include wool, feathers, hair, nails, beak, scales, etc. Due to its favourable chemical and physical properties, keratin has attracted great interest in recent years in the field of biomedicine, pharmaceuticals (e. g. tissue engineering), and cosmetics. Some of the sources of keratin can be obtained practically for free, as many represent waste biomass or residue in different types of industry. A good example is the meat and poultry industry, where large amounts of wool and feather waste are produced worldwide. According to statistics from the US Food and Agriculture Organisation (FAO), global meat production reached 342 million tonnes in 2018. This indicates that a very large amount of keratin-rich waste biomass was also produced. While the low price of these keratin-rich resources is convenient, by repurposing and reusing them, we are also benefiting the environment, as these waste products would otherwise be burned (increasing content of CO2 equivalents in the atmosphere), buried or dumped in landfills. In this master’s thesis, the isolation of keratin from waste sheep wool and poultry feathers by alkaline hydrolysis was performed. Aqueous solution of NaOH of different concentrations was used as an alkaline medium (30 mg/ml, 40 mg/ml, and 50 mg/ml). Experiments were carried out at different reaction times (1 h, 2 h and 3 h) and operating temperatures (50 °C, 65 °C and 80 °C). The influence of these three input variables on keratin molecular weight and isolation yield was then investigated by response surface methodology (Box-Behnken). After the alkaline hydrolysis, the reaction product was a clear, orange liquid. Small quantities of undegraded starting material were still present in the post-reaction mixture, especially at low temperatures (50 °C) and low NaOH (aq) concentrations (30 mg/ml). The isolation yield was relatively low and ranged from 41.68%–66.69% for wool, and from 38.94%–55.20% for feathers. The highest isolation yield from wool (66.69%) was achieved at 50 °C, 3 h, and 40 mg/ml, while the highest isolation yield from feathers (55.20%) was obtained at 50 °C, 2 h, and 50 mg/ml. The molecular weights of the isolated products (keratin) were determined by SDS-PAGE electrophoresis. They were in most cases homogeneously distributed throughout the band, ranging from 4.6 kDa to 315 kDa, but the predominant molecular weight of keratins ranged from 8 kDa to 40 kDa. It was found that higher temperature (80 °C) and concentration of NaOH (aq) (50 mg/ml) decreased the molecular weight of keratin in the samples. All samples from wool and feathers showed relatively low antioxidant activity (maximum 22.19%) and negative zeta potential. Particle size and conductance measurements of the isolates were also performed as well as FTIR analysis. Results of this thesis show that wool and feathers present an excellent source of keratin isolates, and that alkaline hydrolysis of studied waste biomass presents a good possible way of contributing to a clean environment and circular economy.
Sekundarne ključne besede:	keratin;waste biomass;alkaline hydrolysis;wool;feathers;proteins.;
Vrsta dela (COBISS):	Magistrsko delo/naloga
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	1 spletni vir (1 datoteka PDF (XI, 48 f.))
ID:	19874092