Utjecaj iona cinka na metabolički aktivnost bakterija mliječne kiseline

master's thesis

• Title (english): Influence of Zn 2+ ions on metabolic activity of lactic acid bacteria
• Author: Jelena Marinković
• Mentor: Vesna Stehlik-Tomas (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: 2007-10-05, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

U ovom radu ispitan je utjecaj dodatka iona cinka u MRS podlogu na fermentacijsku aktivnost bakterija mliječne kiseline (BMK) te njihovu ugradnju u bakterije: Leuconostoc mesenteroides L3, Lactobacillus brevis L62 i Lactobacillus plantarum L73. Fermentacije su provedene pri 32 ºC u semiaerobnim uvjetima uz dodatak 0 - 300 mg/L iona cinka dodanog u obliku ZnSO4. Dobiveni rezultati su pokazali da dodatak iona cinka u navedenim koncentracijama nema značajan utjecaj na fermentacijsku aktivnost navedenih bakterija. S druge strane, zabilježeno je proporcionalno povećanje mase ugrađenih iona cinka u biomase bakterija dodatkom navedenih koncentracija iona cinka. Ugradnja je bila najveća u prva tri sata fermentacije. Rezultati su pokazali da je koncentracija od 300 mg/L iona cinka dodanih u podlogu optimalna za ugradnju u BMK. Pri ovoj koncentraciji masa ugrađenih iona cinka iznosila je 1,7 mg/g s.tv., 0,9 mg/g s.tv., 0,3 mg/g s.tv., za Leuconostoc mesenteroides L3, Lactobacillus brevis L62 i Lactobacillus plantarum L73. Rezultati su također pokazali da ioni cinka vezani na bakterijsku biomasu nemaju značajan utjecaj na preživljavanje ispitivanih bakterijskih vrsta u simuliranim uvjetima gastrointestinalnog trakta.

Abstract (english)

The aim of this work was to study the influence of Zn+2 ions added in MRS media on fermentation activity of some lactic acid bacteria (LAB) and their incorporation in LAB. For that purposes the accumulation of zinc ions by Leuconostoc mesenteroides L3, Lactobacillus brevis L62, Lactobacillus plantarum L73 was demonstrated. During fermentations the concentration of 0 - 300 mg/L zinc ions added as ZnSO4 in media was used. The fermentations were performed at 32 °C in semi-aerobic conditions. The obtained results have shown that the addition of zinc ions in presented concentrations have no significant effect on fermentation activity and growth of examined LAB. On the other hand, the accumulation of zinc ions by all used bacteria depended on the concentration of Zn+2 ions, and showed linear increase due to the Zn+2 concentration in media. The rate of accumulations was the highest during first three hours of cultivation. Results have shown that the optimal concentration of Zn+2 ions in media for accumulation in LAB was 300 mg/L. At optimal concentration accumulated zinc ions were as follows: 1,7 mg/g d.w., 0,9 mg/g d.w., 0,3 mg/g d.w. for Leuconostoc mesenteroides L3, Lactobacillus brevis L62 and Lactobacillus plantarum L73, respectively. Results have also shown that the Zn+2 ions incorporated in LAB have no significant effect on survival of examined LAB in the simulated gastrointestinal conditions.

• Keywords: bakterije mliječne kiseline; cink; mikroelementi
• Keywords (english): lactic acid bacteria; microelements; zinc
• Language: croatian
• URN:NBN: urn:nbn:hr:159:597540
• Study programme: Title: Biotechnology; specializations in: Biochemical Engineering; Course: Biochemical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo (diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-09-06 08:04:14