Rapid chemotaxonomic profiling for the identification of high-value carotenoids in microalgae

Microalgae hold considerable promise as biofactories for the mass production of high-value metabolites. In this study, 110 strains isolated from waterbodies of the West of Ireland were successfully brought into culture. Chemotaxonomic pigment profiles were obtained in under 7 min using a C₁₈ monolithic HPLC column. This method provided good reproducibility and baseline resolution for 30 of the 54 pigments detected in the culture collection and mixed pigment extracts. Twelve of the isolated strains exhibiting promising carotenoid profiles were selected to further investigate carotenoid cell contents in a batch culture mode, which typically showed higher yields during the exponential phase. Candidates for future carotenoid biorefinery include Brachiomonas submarina (6.1 mg g⁻¹ DW lutein), Rhodella sp. (0.80 mg g⁻¹ DW zeaxanthin) and cf. Amphora sp. (3.3 mg g⁻¹ DW fucoxanthin). This study demonstrates the monolithic HPLC column as a useful screening tool for the rapid chemotaxonomic characterisation and selection of promising strains from culture collections warranting further investigation for physiological optimisation and up-scaling in photobioreactors.