Metabolite Profiling of a Robust Cyanobacterium for Industrial biotechnology

Cyanobacteria produce a variety of metabolites with diverse functions and bioactive properties that have potential uses in industrial biotechnology. Metabolomic profiles closely relate to the physiology of an organism and can be used to investigate any alteration in metabolism and production of industrially relevant metabolites. Little work has been conducted on metabolomic time-course profiles within cyanobacteria with the majority of research on targeted metabolite level changes during abiotic stress such as ultraviolet (UV) radiation. In this thesis the metabolite profile analysis of the less well investigated cyanobacterium; Chlorogloeopsis fritschii (C. fritschii) PCC 6912 was undertaken. The main aim was to evaluate changes in low molecular weight metabolite levels during standard growth and UV exposure using gas chromatography-mass spectrometry (GC-MS). The focus was on identifying biologically relevant metabolites with roles in cyanobacterial metabolism associated with growth phases and adaptation to UV stress. Extracts were assessed using in vitro assays for extraction of potential anti-inflammatory and antibacterial activity from the cyanobacteria with complementary metabolomic analysis utilised for identification of potential active metabolites. Results demonstrated a significant reduction in intracellular metabolites involved in carbon and nitrogen metabolism during UV-B exposure with a higher proportion of metabolites increasing in levels during UV-A exposure. Pre-treatment of C. fritschii to low dose UV prior to high dose UV had a lesser effect on metabolism indicating stress tolerance and adaptation to UV stress. Metabolite levels were seen to reflect the changing growth phases over 120 days during standard conditions with overall similarity in metabolite levels between axenic and xenic cultures over 28 days. Finally, extracts showed promising anti-inflammatory and antibacterial activity with identification of potential active metabolites with relevance to personal care products. This is the first GC-MS based metabolite profiling of C. fritschii during standard growth and UV exposure. This builds on the experimental data and knowledge-base already available for cyanobacteria, including C. fritschii, for their potential use in industrial biotechnology.