Identifikacija i karakterizacija bakterija mliječne kiseline izoliranih iz brašna ekološki uzgojenih žitarica

master's thesis

• Title (english): Identification and characterization of lactic acid bacteria isolated from organic flours
• Author: Ines Ivanuša
• Mentor: Jasna Mrvčić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Fermentation and Yeast Technology); Zagreb
• Defense date and country: 2013-09-26, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Izolirane, identificirane i okarakterizirane su bakterije mliječne kiseline (BMK) prirodno prisutne u brašnu ekološki uzgojenih žitarica. Identifikacija je provedena na osnovu spektrometrije masa pomoću Microflex LT™ MALDI-TOF instrumenta. Identificiranim vrstama određena je fermentativna i antimikrobna aktivnost. Produkti fermentacije određeni su visoko učinkovitom tekućinskom kromatografijom dok je antimikrobna aktivnost određivana metodom s dvostrukim slojem agara te turbidimetrijski. Rezultati su pokazali da su korišteni uzorci brašna imali bogatu mikrofloru. Izolirano je ukupno 16 BMK i 1 kvasac pri čemu nije uočena značajna razlika u broju i vrstama kultura izoliranih iz ekoloških i konvencionalnih uzoraka brašna. Kod pšeničnog brašna uočena je manja biološka raznolikost u odnosu na raženo brašno i brašno pira. Rodovi Lactobacillus i Enterococcus bili su najzastupljeniji rodovi u ispitivanim uzorcima brašna. Od izoliranih bakterijskih vrsta, vrste Lactobacillus farciminis, Pediococcus pentosaceus, Leuconostoc citreum i Lactobacillus brevis pokazale su veću fermentativnu aktivnost. Vrste Lactobacillus brevis, Pediococcus pentosaceus, Weissella cibaria i Lactobacillus farciminis izolirane iz ekološki uzgojenih žitarica pokazale su značajnu antimikrobnu aktivnost prema A. niger i Penicillium sp. Međutim, inhibicija nije bila značajnija u odnosu na sojeve bakterija uzetih iz zbirke Laboratorija za tehnologiju vrenja i kvasca.

Abstract (english)

In this thesis naturally occurring lactic acid bacteria (LAB) in organic flour were isolated. Identification was based on mass spectrometry using a Microflex LT ™ MALDI-TOF instrument. Fermetative and antimicrobial activity of indentified spieces was determined. Fermentation products were determined by high pressure liquid chromatography while the antimicrobial activity was determined using a overlay agar method and turbitimer. The results showed that the used samples of flour had a rich flora. There were total of 16 LAB and 1 yeast isolated with no significant difference in the number and types of cultures isolated from organic and conventional flour.Wheat flour showed less bidiversity than the rye and spelled flour. The most common genera in the tested flour were Lactobacillus and Enterococcus. Isolated Lactobacillus farciminis, Pediococcus pentosaceus, Leuconostoc citreum and Lactobacillus brevis showed the best fermentation activity. Lactobacillus brevis, Pediococcus pentosaceus, Weissella cibaria and Lactobacillus farciminis isolated from organic grains showed significant antimicrobial activity against A. niger and Penicillium sp. However, the inhibition was not significant compared to laboratory strains of these bacterial species.

• Keywords: ekološka proizvodnja; izolacija i identifikacija; bakterije mliječne kiseline; kiselo tijesto; antimikrobna aktivnost
• Keywords (english): organic production; isolation and identification; lactic acid bacteria; sourdough; antifungal activity
• Language: croatian
• URN:NBN: urn:nbn:hr:159:474131
• 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: Access restricted to students and staff of home institution
• Created on: 2017-05-04 11:47:16