Detekcija kvasaca iz roda Brettanomyces i njihov utjecaj u biotehnološkoj industrijskoj proizvodnji alkoholnih pića i bioetanola

undergraduate thesis

• Title (english): Detection of yeasts from genus Brettanomyces and their influence in biotechnological industrial production of alcoholic beverages and bioethanol
• Author: Isabela Pehar
• Mentor: Anita Slavica (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for Biochemical Engineering, Industrial Microbiology and Malting and Brewing Technology); Zagreb
• Defense date and country: 2018-06, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Kvasci vrste Bretanomyces bruxellensis mogu se izolirati iz različitih staništa. Detekcija ove vrste kvasaca, njezin rast i druge fiziološke karakteristike slabo su okarakterizirane zbog nedostataka raspoloživih analitičkih i molekularnih metoda. Ova vrsta može koristiti određene monosaharide (i pentoze), di- i polisaharide i neke druge neobične susptrate. Prisutnost kisika utječe na regulaciju metabolizma različitih supstrata u stanicama ove vrste, koja pokazuje Crabtree-jev i Custer-ov učinak. Specifični krajnji proizvodi metabolizma B. bruxellensis su 4-etilfenol i 4-etilgvajakol, koji pri niskim koncentracijama doprinose kompleksnosti organoleptičkih svojstava vina i piva, dok visoke koncentracije ovih krajnjih proizvoda formiraju tzv. „brett“ aromu ovih alkoholnih pića i tako ih čine neprihvatljivima krajnjem potrošaču. Primjena različitih starter-kultura i tretiranje podloga u kojima rastu ovi kvasci električnom strujom niske jakosti mogu spriječiti kontaminacije i/ili smanjiti broj stanica kvasaca iz roda Bretanomyces u različitim biotehnološkim proizvodima.
Eksperimentalni podaci ukazuju da je vrsta Bretanomyces bruxellensis robustan
biokatalizator, koji zadržava svoju metabolički aktivnost pri relativno visokim koncentracijama
supstrata i proizvoda (etanola), zatim niskim pH vrijednostima i visokom osmotskom tlaku,
pa je industrijska primjena ove vrste u proizvodnji bioetanola vrlo izgledna.

Abstract (english)

Yeasts from species Bretanomyces bruxellensis can be isolated from different habitants. Detection of this species, its growth and other physiological characteristics have been poorly known due to absence of available analytical and molecular methods. The species can use specific monosaccharides (and pentoses), di- and polisaccharides as well as some unusual substrates. Presence of oxygen affects regulation of metabolism of different substrates in the cells and Crabtree and Custer effects have been detected in the yeast species. Specific end products manufactured by B. bruxellensis are 4-ethylphenol and 4-ethylguaiacol. These products at lower concentrations contribute to complexity of organoleptic properties of wine and beer, while the two products at higher concentrations form so called brett aroma of those alcoholic beverages and thus make them unacceptable to consumer. Implementation of different starter cultures and treatment of media in which the yeast species grows by low electric current can prevent contamination and/or reduce number of the yeast cells in different biotechnological products. Experimental data show that species Bretanomyces bruxellensis is robust biocatalyst which retains its metabolic activity under relatively high concentration of substrate and product (ethanol), low pH values, and high osmotic pressure. Therefore, application of the species in bioethanol production seems very promising.

• Keywords: kvasci iz roda Brettanomyces; vrsta Brettanomyces bruxellensis; analitičke i molekularne metode; alkoholna pića; bioetanol
• Keywords (english): yeasts from genus Brettanomyces; species Brettanomyces bruxellensis; analytical and molecular methods; alcoholic beverages; bioethanol
• Language: croatian
• URN:NBN: urn:nbn:hr:159:604923
• Study programme: Title: Biotechnology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-06-24 10:40:19