Mass Spectrometry Based Metabolomic and Lipidomic Analyses of Algal Biomass.

Abstract

Background: In a project at UiT - the Arctic University of Norway, the lipid profile of the microalgal biomass from the specie Porosira glacialis is mapped using HRMS lipidomic analyses to evaluate the potential for the biomass to be used as fish feed. At the same time, it is desired to screen the same biomass for bioactivities using bioassays in combination with HRMS metabolomic analyses. The two processes use two different extraction methods. To evaluate the differences between the extraction methods, a comparison between one of each extract was done in this thesis. Fractions from extracts are also tested for bioactivity and analysed on HRMS to initiate the mapping of bioactivity.

Method: Microalgal biomass of P. glacialis was extracted using two different extraction methods, yielding an aqueous, an organic and a lipid extract. The metabolic and lipidomic profile of the organic and the lipid extract was compared using HRMS metabolomic and lipidomic analyses. The aqueous and the organic extracts were fractionated using flash chromatography, before being tested for various bioactivities and analysed using HRMS. Observed activity was investigated and a potential bioactive compound was isolated and tested for anti-cancer activity.

Results: There were no obvious differences in the metabolomic and lipidomic profiles between the organic and the lipid extracts, but some trends could be observed. The lipidomic analyses showed low lipid detection not consistent with previous research, which needs further investigation. In fractions obtained from the microalgal biomass from P. glacialis, anticancer activity against human melanoma A2058 cancer cells and growth inhibition against the bacteria Streptococcus agalactiae were observed, as well as anti-inflammatory activity in an ELISA immunoassay. An isolated potential bioactive compound showed no activity against human melanoma A2058 cancer cells at five different test concentrations.

Conclusion: None of the extraction methods can be considered favourable over the other based on the comparison in this thesis. Various bioactivities were observed for fractions derived from the microalgal biomass of P. glacialis, but more investigation must be done to identify the compounds responsible for the activity.