Utjecaj izvora dušika, ugljika i svjetlosti na kinetiku rasta nesumporne ljubičaste bakterije Rhodovulum adriaticum DSM 2781

master's thesis

• Title (english): Effects of nitrogen, carbon and light sources on growth kinetics of purple non-sulfur bacteria Rhodovulum adriatucum DSM 2781
• Author: Veronika Matoković
• Mentor: Mario Novak (mentor)
• Committee member: Antonija Trontel (član povjerenstva)
• 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: 2020-07-17, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Primjena ljubičastih nesumpornih bakterija kao proizvođača komercijalno zanimljivih proizvoda prepoznata je već godinama. Međutim, u svrhu postizanja ekološki i ekonomski održivih bioprocesa, nužan je odabir odgovarajućih obnovljivih sirovina kao i uvjeta uzgoja radnog mikroorganizma. Cilj ovog rada bio je ispitati sposobnost uzgoja bakterije Rhodovulum adriaticum DSM 2781 na različitim izvorima svjetlosti (obična žarulja i bijelo LED svjetlo), uz izvore ugljika koji se dobivaju predobradom lignoceluloznih sirovina te istražiti mogućnost zamjene skupljih izvora dušika (diamonijev fosfat i kvaščev ekstrakt) s kukuruznom močevinom. Rezultati istraživanja pokazali su da ispitivani izvori svjetlosti utječu na sintezu pigmenata, ali ne i na brzinu rasta. Tijekom mikroaerofilnih uzgoja na svjetlu, prinos biomase, brzina rasta i koeficijent konverzije supstrata u biomasu povećavaju se s porastom koncentracije kukuruzne močevine u podlozi. U istim uvjetima uzgoja, koncentracije diamonijeva fosfata u podlozi nisu imale značajniji utjecaj na dobivene pokazatelje uspješnosti. Proveden je i šaržni uzgoj bakterije u aerobnim uvjetima u mraku u bioreaktoru s miješalom. Uzgoj na podlozi s glukozom i ksilozom kao izvorima ugljika te s diamonijevim fosfatom i kvaščevim ekstraktom kao izvorima dušika rezultirao je najboljim pokazateljima uspješnosti procesa (YX = 2,819 g Lˉ¹; Pr = 0,117 g Lˉ¹ hˉ¹; YX/S = 0,521 g gˉ¹; μ = 0,551 hˉ¹).

Abstract (english)

The application of purple non-sulfur bacteria as producers of commercially interesting products has been recognized for years. However, in order to achieve ecologically and economically sustainable bioprocesses, it is necessary to select appropriate renewable feedstock as well as optimal growing conditions for the working microorganism. The aim of this study was to examine the ability of bacteria Rhodovulum adriaticum DSM 2781 to grow under different light sources (incandescent light and white LED light), on carbon sources obtained after pretreatment of lignocellulosic feedstock and to explore the possibility of replacing expensive nitrogen sources (diammonium phosphate and yeast extract) with corn steep liquor. Current study found that the examined light sources affect the synthesis of pigments, but not the bacterial growth rate. Under light-micro oxygen conditions, an increase in biomass yield, growth rate and biomass-to-supstrate yield coefficient with increasing initial concentrations of corn steep liquor in the medium was observed. Under the same growing conditions, different diammonium phosphate concentrations in the medium did not have a significant effect on the obtained performance indicators. Batch cultivation under dark/aerobic conditions in a stirred tank bioreactor was also investigated. Bacterial growth on glucose and xylose as carbon sources and with diammonium phosphate and yeast extract as nitrogen sources in the medium resulted with the best performance indicators (YX = 2.819 g Lˉ¹; Pr = 0.117 g Lˉ¹ hˉ¹; YX/S = 0.521 g gˉ¹; μ = 0.551 hˉ¹).

• Keywords: ljubičaste nesumporne bakterije; Rhodovulum adriaticum DSM 2781; izvori dušika; izvori svjetlosti; bioreaktor s miješalom
• Keywords (english): purple non-sulfur bacteria; Rhodovulum adriaticum DSM 2781; nitrogen source; light source; stirred tank bioreactor
• Language: croatian
• URN:NBN: urn:nbn:hr:159:574427
• 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: 2020-07-20 12:33:29