Različite tehnike proizvodnje medovine uz pomoć kvasca Saccharomyces cerevisiae ZIM 3418

master's thesis

• Title (english): Different tecnhiques of mead production with yeast Saccharomyces cerevisiae ZIM 3418
• Author: Petra Akalović
• Mentor: Mladen Pavlečić (mentor)
• Committee member: Mario Novak (predsjednik povjerenstva)
• Committee member: Jasna Mrvčić (član povjerenstva)
• Committee member: Damir Stanzer (član povjerenstva)
• 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: 2024-09-20, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Medovina je alkoholno piće nastalo dugotrajnom fermentacijom medne sladovine, dobivene razrjeđivanjem meda s vodom, najčešće pomoću selekcioniranih vinskih kvasaca. Budući da med ne sadrži dovoljno hranjivih tvari potrebnih za kvaščevu aktivnost, preporuča se dodatak nutrijenata u sladovinu za poboljšanje i ubrzanje fermentacije. U preliminarnom dijelu ovog rada, provedenog u tikvicama, proučavana je mogućnost proizvodnje medovine od lipinog meda pomoću kvasca Saccharomyces cerevisiae ZIM 3418 iz sladovine s različitom početnom koncentracijom kvaščevog ekstrakta kao izvora dušika (0 g/L, 0,5 g/L i 2 g/L) s ciljem proučavanja njegovog utjecaja na dinamiku fermentacije. Ostvareni prinosi etanola u eksperimentima u tikvicama redom su iznosili 21,07 g/L, 33,76 g/L i 43,95 g/L što ukazuje na pozitivan utjecaj veće količine dodanog kvaščevog ekstrakta na koncentraciju proizvedenog alkohola. Nakon određivanja optimalne koncentracije kvaščevog ekstrakta, provedene su dvije fermentacije u bioreaktoru s miješalom koristeći dva različita postupka proizvodnje; šaržni i polukontinuirani, s ciljem usporedbe pokazatelja uspješnosti između ta dva postupka. U ovom slučaju zabilježeni su slični prinosi etanola tijekom oba postupka proizvodnje, a iznosili su 44,23 g/L za šaržni postupak i 47,86 g/L za polukontinuirani postupak. Koeficijent konverzije fermentabilnih šećera u etanol za šaržni postupak iznosio je 0,3709 g/g, a za polukontinuirani postupak 0,3579 g/g te je ostvarena produktivnost od 0,6884 g/Lh tijekom šaržnog i 0,6789 g/Lh tijekom polukontinuiranog postupka proizvodnje. Na temelju rezultata ovog diplomskog rada može se zaključiti kako dodatak odgovarajuće koncentracije kvaščevog ekstrakta u sladovinu od lipinog meda bitno utječe na konačni prinos etanola te da se za proizvodnju medovine mogu koristiti i šaržni i polukontinuirani postupak.

Abstract (english)

Mead is an alcoholic drink created by long-term fermentation of honey wort, obtained by diluting honey with water, usually using selected wine yeasts. Since honey does not contain enough nutrients necessary for yeast activity, it is recommended to add nutrients to the wort to improve and accelerate fermentation. In the preliminary part of this thesis, carried out in flasks, the possibility of producing linden honey mead using the yeast Saccharomyces cerevisiae ZIM 3418 from wort with different initial concentrations of yeast extract as a nitrogen source (0 g/L, 0.5 g/L and 2 g) was studied with the aim of studying its influence on fermentation dynamics. The achieved yields of ethanol in these experiments were 21,07 g/L, 33,76 g/L and 43,95 g/L, respectively, which indicates a positive influence of a larger amount of added yeast extract on the concentration of produced alcohol. After determination of optimal concentration of yeast extract, two fermentations were carried out in a stirred tank bioreactor by using two different production techniques namely batch and semi-continuous, with the aim of comparing bioprocess efficiency parameters between them. Similar results were achieved by using both techniques, where ethanol yield of 44,23 g/L for the batch and 47,86 g/L for the semi-continuous process was obtained. The conversion coefficient of fermentable sugars into ethanol for the batch process was 0,3709 g/g, and for the semi-continuous process 0,3579 g/g while the productivity in case of batch process was 0,6884 g/Lh, and that of the semi-continuous process was 0,6789 g/Lh respectively. Based on the results of this thesis, it can be concluded that the addition of a suitable concentration of yeast extract to linden honey mead significantly affects the final yield of ethanol and that both production techniques can be used for mead production in stirred tank bioreactor.

• Keywords: medovina; Saccharomyces cerevisiae ZIM 3418; kvaščev ekstrakt; bioreaktor s miješalom
• Keywords (english): mead; Saccharomyces cerevisiae ZIM 3418; yeast extract; stirred tank bioreactor
• Language: croatian
• URN:NBN: urn:nbn:hr:159:700912
• Study programme: Title: Bioprocess Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka bioprocesnog inženjerstva (magistar/magistra inženjer/inženjerka bioprocesnog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-10-21 10:47:42