Karakterizacija amilolitičke aktivnosti bakterije Lactobacillus amylovorus DSM 20531T određivanjem koncentracije jednostavnijih ugljikohidrata tekućinskom kromatografijom visoke učinkovitosti

master's thesis

• Title (english): Characterization of amylolytic activity of bacterium Lactobacillus amylovorus DSM 20531T by determining concentration of simpler carbohydrates using high-pressure liquid chromatography
• Author: Vedrana Tadić
• 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: 2010-06, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

U ovom radu istraživana je mogućnost određivanja koncentracije jednostavnijih ugljikohidrata: glukoze (G1), maltoze (G2), maltotrioze (G3), maltotetraoze (G4), maltopentaoze (G5), maltoheksaoze (G6) i maltoheptaoze (G7) u supernatantima uzoraka koji su izuzeti tijekom uzgoja amilolitičke bakterije mliječne kiseline Lactobacillus amylovorus DSM 20531T u gustoj suspenziji kukuruzne krupice u laboratorijskom bioreaktoru s miješalom šaržnim postupkom. Za analizu ovih uzoraka kompleksnog sastava odabrana je ion-izmjenjivačka kromatografija visoke učinkovitosti (kolona SupelcogelTM C-610H s predkolonom SupelcogelTM H; RID-10A; V = 20 μL, θ = 30°C, F = 0,1 mL min-1) pomoću koje su određene koncentracije nekih jednostavnijih ugljikohidrata (G1 - G4) kao i ukupna koncentracija maltopentaoze, maltoheptaoze i maltoheksaoze (G5 + G6 + G7). Amilolitička aktivnost bakterije L. amylovorus DSM 20531T obuhvaća hidrolizu škroba iz kukuruzne krupice do homopolimera s višim (GN, N > 7) i nižim stupnjem polimerizacije (GN, N ≤ 7) do maltoze (G2), dok glukoza (G1) nije detektirana ni u jednom analiziranom uzorku. U odabranim uvjetima ova je amilolitička bakterija potpuno hidrolizirala i homolaktički fermentirala 36 % škroba iz kukuruzne krupice do mliječne kiseline. Preostali dio od 64 % škroba hidroliziran je do G2 - G7, od čega 41 % čini maltoza (G2). Kinetika hidrolize škroba do detektiranih jednostavnijih ugljikohidrata upućuje da amilolitička aktivnost L. amylovorus DSM 20531T obuhvaća minimalno enzim α-amilazu čija je aktivnost konstitutivna i može se inducirati.

Abstract (english)

In this work the possibility for determining concentrations of simpler carbohydrates: glucose (G1), maltose (G2), maltotriose (G3), maltotetraose (G4), maltopentaose (G5), maltohexaose (G6) and maltoheptaose (G7) was investigated. These concentrations have been determined in supernatants of samples whithdrawn during batch cultivation of amylolytic lactic acid bacterium Lactobacillus amylovorus DSM 20531T in the dense corn grits suspension in a lab-scale stirred tank bioreactor. Ion-exchange high-pressure liquid chromatography (analitical column SupelcogelTM C- 610H with pre-column SupelcogelTM H; RID-10A; V = 20 μL, θ = 30°C, F = 0,1 mL min-1) was chosen for analysis of those complex samples and the concentrations of some simpler carbohydrates (G1 - G4) as well as total concentration of maltopentaose, maltohexaose and maltoheptaose (G5 + G6 + G7) were determined in them. Amylolytic activity of bacterium L. amylovorus DSM 20531T comprises hydrolysis of corn grits - starch to homopolymers with higher (GN, N > 7) and lower degree of polymerisation (GN, N ≤ 7) to maltose (G2), while glucose (G1) has not been detected in the analysed samples. Under chosed conditions this amylolytic bacterium hidrolyses completely and during homolactic fermentation converts 36 % of corn grits - starch to lactic acid. Remaining 64 % of starch have been hydrolysed to G2 - G7, and 41 % of it is maltose (G2). Kinetic of starch hydrolysis to detected simpler carbohydrates suggests that amylolytic activity of L. amylovorus DSM 20531T comprises minimaly enzyme α-amylase, activity of the enzyme is constitutive and it can be induced.

• Keywords: amilolitička aktivnost; Lactobacillus amylovorus; škrobne sirovine; α-amilaza; jednostavniji ugljikohidrati; tekućinska kromatografija visoke djelotvornosti (HPLC)
• Keywords (english): amylolytic activity; Lactobacillus amylovorus; starch-containing substrates; α-amylase; simpler carbohydrates; high-pressure liquid chromatography (HPLC)
• Language: croatian
• URN:NBN: urn:nbn:hr:159:052575
• 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: 2017-08-28 11:18:58