Fiziologija heterofermentativnog soja Leuconostoc mesenteroides LMG 7954 pri različitim uvjetima uzgoja šaržnim postupkom u laboratorijskom mjerilu

master's thesis

• Title (english): Physiology of heterofermentative strain Leuconostoc mesenteroides LMG 7954 under different conditions of batch cultivation in the laboratory scale
• Author: Ana-Marija Gruičić
• 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: 2019-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

U istraţivanjima u ovom radu utvrĎen je utjecaj koncentracije otopljenog kisika na rast soja Leuconostoc mesenteroides LMG 7954 u kemijski djelomično definiranoj podlozi (Vandamme i sur., 1987.) pri 28±1,0°C i opadajućoj pH vrijednosti suspenzije tijekom uzgoja šarţnim postupkom u laboratorijskom mjerilu. Razvijena je i optimirana ionsko-izmjenjivačka HPLC metoda, kojom je popraćena aktivnost ovog soja u različitim uvjetima uzgoja šarţnim postupkom. L. mesenteroides LMG 7954 uspješno raste u hranjivoj MRS podlozi, kemijski djelomično definiranoj hranjivoj podlozi kao i u smjesi visokog osmotskog tlaka saharoza:glicerol. Ovaj soj moţe transportirati i metabolizirati glukozu, saharozu (glukozu i fruktozu) i glicerol. Glavni proizvodi metabolizma ovih ugljikohidrata i alkohola su bakterijska biomasa i laktat te znatno manje koncentracije acetata i etanola. U smjesi saharoza:glicerol ova Gram-pozitivna bakterija raste slijedeći eksponencijalni trend, a zatim linearni trend. Ova vaţna fiziološka karakteristika kvalificira ovaj soj za industrijsku primjenu u podlogama s visokim početnim koncentracijama supstrata. Primjenom ultrazvuka i dodatkom Tween-a-80 permeabilizirane su stanice ovog soja i to tijekom njihova rasta u smjesi saharoza:glicerol. Obje metode utječu na metabolizam supstrata u stanicama ove (navodno) mikroaerofilne heterofermentativne bakterije mliječne kiseline, kako je to utvrĎeno HPLC metodom. Nadalje, identificiran je dodatni pik u kromatogramima, koji ukazuje na mogućnost proizvodnje -glukozilglicerola s pomoću ovog soja.

Abstract (english)

In investigation described in this work effect of dissolved oxygen on the growth of strain Leuconostoc mesenteroides LMG 7954 in chemically semi-defined broth (Vandamme et al., 1987) was determined at 281.0°C and decreasing pH value of suspension during batch cultivation in the laboratory scale. Ion-exchange HPLC method was developed and optimized in order to follow activity of the strain under different conditions of the batch cultivation. L. mesenteroides LMG 7954 grew in MRS broth, the chemically semi-defined broth and sucrose:glycerol mixture with high osmotic pressure. The strain is able to transport and metabolize glucose, sucrose (glucose and fructose) and glycerol. The main end-products of metabolism of those carbohydrates and alcohol are bacterial biomass and lactate, while significantly lower concentration of acetate and ethanol were detected. In the sucrose:glycerol mixture this Gram-positive bacterium grew first exponentially and then followed linear trend. This physiological characteristic can be very useful in industrial application of the strain, especially in the cultivations with high initial concentration of substrate(s). Cells of this strain were permeabilized when growing in the sucrose:glycerol mixture by using ultrasound treatment and addition of Tween-80. Metabolism of the substrates in the cells of these (apparently) microaerophilic heterofermenative lactic acid bacterium was affected by both methods, as determined by HPLC method. Furthermore, additional peak was identified within HPLC chromatograms which indicates possibility for production of -glucosyglycerol by the strain.

• Keywords: fiziologija; α-glukozilglicerol; HPLC; Leuconostoc mesenteroides LMG 7954; permeabilizacija stanica
• Keywords (english): cell permeabilization; α-glucosyglycerol; HPLC; Leuconostoc mesenteroides LMG 7954; physiology
• Language: croatian
• URN:NBN: urn:nbn:hr:159:615416
• 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: 2019-12-16 13:22:00