Utjecaj temperature uzgoja na proizvodnju mliječne kiseline s pomoću bakterije Lactobacillus amylovorus DSM 20531T

master's thesis

• Title (english): Effect of cultivation temperature on production of lactic acid by bacterium Lactobacillus amylovorus DSM 20531T
• Author: Vanda Baršić
• 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: 2008-12-18, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

U ovom je radu istraživan utjecaj različitih temperatura uzgoja na rast amilolitičke bakterije Lactobacillus amylovorus DSM 20531T i proizvodnju mliječne kiseline. Uzgoj bakterijske kulture proveden je u modificiranoj MRS podlozi u koju je umjesto glukoze (20 g L-1) dodan topljivi škrob (10 g L-1). Odabrane su četiri različite temperature (30°C, 35°C, 45°C i 50°C) za uzgoj ove bakterije i proizvodnju mliječne kiseline u laboratorijskom bioreaktoru s miješalom šaržnim postupkom. L. amylovorus DSM 20531T istovremeno provodi hidrolizu škroba i fermentira nastale saharide do mliječne kiseline. U opisanim uvjetima ova bakterija može rasti i provoditi homolaktičnu fermentaciju pri temperaturama od 30°C, 35°C i 45°C, dok su pri 50°C rast i aktivnost ove bakterije zanemarivi. Maksimalna brzina potrošnje topljivog škroba (0.89 h-1) i maksimalna specifična brzina rasta L. amylovorus DSM 20531T (0.87 h-1) postignute su pri 45°C. Maksimalna brzina proizvodnje mliječne kiseline s pomoću ove amilolitičke bakterije postignuta je pri temperaturi od 45°C i iznosila je 2.01 h-1. Pri ovoj je temperaturi procijenjena i najveća produktivnost proizvodnje mliječne kiseline (PrP = 1.45 g L-1 h-1).

Abstract (english)

In this work effect of different cultivation temperatures on growth of amylolytic bacterium Lactobacillus amylovorus DSM 20531T and production of lactic acid was investigated. The growth of bacterial culture was carried out in modified MRS medium with soluble starch (10 g L-1) instead of glucose (20 g L-1). Four different temperatures (30°C, 35°C, 45°C and 50°C) were chosen for the production of lactic acid by the bacterium during batch cultivation in a stirred-tank lab bioreactor. L. amylovorus DSM 20531T simulatneously hydrolizes starch and ferments saccharides therefrom to lactic acid. Under described conditions the bacterium grows and conducts homolactic fermentation at temperatures of 30°C, 35°C and 45°C, while at 50°C the growth and activity of the bacterium are negligible. Maximal soluble starch uptake rate (0.89 h-1) and maksimal specific growth rate of L. amylovorus DSM 20531T (0.87 h-1) were obtained at 45°C. Maximal lactic acid production rate of 2.01 h-1 was attained at 45°C. Also, at this temperature maximal productivity of lactic acid production was estimated (PrP = 1.45 g L-1 h-1).

• Keywords: mliječna kiselina; šaržni uzgoj; temperatura uzgoja; Lactobacillus amylovorus; HPLC
• Keywords (english): lactic acid; batch cultivation; temperature of cultivation; Lactobacillus amylovorus; HPLC
• Language: croatian
• URN:NBN: urn:nbn:hr:159:257926
• 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: 2017-08-31 10:03:09