Utjecaj kisika i ugljikovog dioksida na rast i aktivnost bakterije mliječne kiseline Lactobacillus coryniformis subsp. torquens DSM 20004T

master's thesis

• Title (english): Effect of oxygen and carbon dioxide on the growth and activity of lactic acid bacterium Lactobacillus coryniformis subsp. torquens 20004T
• Author: Katarina Hviezd
• 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: 2014-09-17, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Visoka koncentracija kisika, koji je otopljen u suspenziji, pospješuje iscrpljivanje glukoze iz hranjive MRS podloge s pomoću soja Lactobacillus coryniformis subsp. torquens DSM 20004T. Smanjena koncentracija kisika i dobava ugljikovog dioksida pogoduju sintezi biomase ovog bakterijskog soja i proizvodnji D-(-)-laktata (P1) (YP1/S = 0,94 g/g), jednog od dva krajnja proizvoda metabolizma glukoze. Fakultativno heterofermentativni soj L. coryniformis subsp. torquens DSM 20004T tijekom rasta u hranjivoj MRS podlozi, koja sadrži relativno visoku koncentraciju acetata (c0 = 60,5 mmol/L), proizvodi i acetat kao krajnji proizvod metabolizma (P2). Na proizvodnju acetata utječu koncentracija glukoze kao i koncentracija kisika i ugljikovog dioksida u podlozi. Kao načini regulacije metabolizma glukoze i proizvodnje D-(-)-laktata i acetata kod ove Gram-pozitivne bakterije identificirani su i okarakterizirani (1) „acetatni prekidač“ i (2) limitacija glukozom (cS < 42,0 – 50,0 mmol/L).

Abstract (english)

Depletion of glucose from MRS medium by Lactobacillus coryniformis subsp. torquens DSM 20004T was enhanced at relatively high concentration of dissolved oxygen. Synthesis of bacterial biomass and production of D-(-)-lactate (P1) (YP1/S = 0,94 g/g), one of two end-products of glucose metabolism, were favored at decreased concentration of dissolved oxygen and increased concentration of carbon dioxide. During growth in the MRS medium, which contains relatively high concentration of acetate (c0 = 60,5 mmol/L), species L. coryniformis subsp. torquens DSM 20004T produced second end-product - acetate (P2). Production of acetate was affected by concentration of glucose and concentration of dissolved oxygen and carbon dioxyde. „Acetate switch“ and glucose limitation (cS < 42,0 – 50,0 mmol/L) were identified and characterized as mechanisms of regulation of glucose metabolism and production of D-(-)-lactate and acetate by this Gram-positive bacterium.

• Keywords: Lactobacillus coryniformis subsp. torquens; fermentacija glukoze; limitacija glukozom; koncentracija kisika i ugljikovog dioksida u podlozi; proizvodnja D-(-)-laktata i acetata
• Keywords (english): Lactobacillus coryniformis subsp. torquens; glucose fermentation; glucose limitation; concentration of dissolved oxygen and carbon dioxyde; production of D-(-)-lactate and acetate
• Language: croatian
• URN:NBN: urn:nbn:hr:159:318898
• 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: 2017-05-02 08:25:00