Reološka analiza izbranih morskih bakterijskih izolatov

Tramšek, Kaja (author), Stopar, David (mentor), Tinta, Tinkara (co-mentor)

Biopolimeri, ki jih proizvajajo morski mikroorganizmi, nam ponujajo številne nove materiale, ki jih uporabljamo v komercialne namene. Morsko okolje se je v zadnjih letih izkazalo kot zelo obetajoče za odkrivanje novih naravnih produktov. Namen naloge je bil preveriti mehanske lastnosti bakterijskih suspenzij iz zbirke morskih bakterijskih izolatov na Morski biološki postaji v Piranu ter na osnovi reologije najti seve, ki imajo znatno povečano produkcijo zunajceličnih polimerov, ki povečajo viskoznost medija. Izmed pregledanih 76 bakterijskih izolatov smo izbrali dva najobetavnejša, katerih suspenziji sta imeli povečano viskoznost (Loktanella sp. BF5_0537 in Halomonas sp. BF5_0027). Preverili smo vpliv vira ogljika, temperature in slanosti na viskoznost bakterijske suspenzije preučevanih izolatov. Pri obeh izolatih je na zvišanje viskoznosti bakterijske suspenzije kot vir ogljika najbolj vplival dodatek peptona in kvasnega ekstrakta, med enostavnimi viri ogljika pa glicerol. Izolat Loktanella sp. BF5_0537 je imel najvišjo viskoznost pri sobni temperaturi 21 °C in 0,5 M koncentraciji NaCl, izolat Halomonas sp. BF5_0027 pa pri 8 °C in 2 M koncentraciji NaCl. Izolacija bakterijskega izolata glede na letni čas ni korelirala z viskoznostjo izolatov Halomonas sp. in Loktanella sp. Z namenom ugotavljanja pogojev, ki bi v morskem ekosistemu potencialno lahko privedli do povečane viskoznosti, smo pri kontroliranih laboratorijskih pogojih poskušali inducirati cvetenje fitoplanktona, vendar neuspešno.

• Language: Slovenian
• Keywords: biologija, morske bakterije, biopolimeri, eksopolisaharidi, reološka analiza, viskoznost, Halomonas sp., Loktanella sp.
• Work type: Master's thesis/paper
• Organization: BF - Biotechnical Faculty
• Year: 2019
• PID: 20.500.12556/RUL-107796
• COBISS.SI-ID: 5079375
• Publication date in RUL: 26.05.2019

Secondary language

• Language: English
• Title: Rheological analysis of the selected marine bacteria isolates

Abstract

Biopolymers from marine microorganisms offer numerous new materials, which can be used in commercial applications. Marine enviroment proved to be a promising field to discover new natural products. The aim of this thesis was to check mechanical characteristics of selected bacterial suspensions based on their production of extracellular polymers that increase viscosity of the medium. Among 76 examinated bacterial isolates we chose two most promising ones (Loktanella sp. BF5_0537 and Halomonas sp. BF5_0027). In further studies we checked the effect of added carbon, temperature and salinity on viscosity. Peptone and yeast extract had the strongest effect on viscosity of bacterial suspensions, among simple carbon sources glycerol increased viscosity the most. The isolate Loktanella sp. BF5_0537 had the highest viscosity at the room temperature 21 °C and 0,5 M NaCl concentration, isolate Halomonas sp. BF5_0027 had the highest viscosity at 8 °C and 2 M NaCl concentration. There was no correlation between the month of isolation of Halomonas sp. or Loktanella sp. and viscosity. In order to determine the conditions that could potentially lead to increased viscosity in marine ecosystem, we tried to induce blooming of phytoplankton under controlled laboratory conditions, but we were unsuccessful.

• Keywords: biology, marine bacteria, biopolymers, exopolysaccharide, rheology, viscosity, Halomonas sp., Loktanella sp.