Abstract

Marine microalgae, as primary producers, are a significant source of diverse bioactive compounds. To explore this, the endogenous small molecules (metabolites) of four species Chaetoceros curvisetus, Thalassiosira lundiana, Thalassiosira andamanica, and Graesiella emersonii were profiled using Gas Chromatography-Triple Quadrupole Mass Spectrometry (GC-TQMS). Crude aqueous and organic algal extracts were vacuum-dried and subjected to chemical derivatization using silylating agents such as N,O-Bis(trymethylsilyl)trifluroacetamide (BSTFA) and N-Methyl-N-trimethylsilytrifluoroacetamide (MSTFA) to improve GC-MS detection of polar compounds before molecular mass profiling. The results showed no significant difference in essential amino acid production (Isoleucine, Leucine, Phenylalanine, and Threonine) among G. emersonii, C. curvisetus, and T. lundiana (p<0.05, n=3). However, T. andamanica displayed greater concentrations of ergosterol, lactic acid, palmitic acid, and oleic acid, Conversely, T. lundiana showed elevated concentrations of the omega-3 PUFAs DHA and EPA. Whereas G. emersonii contained greater amounts of α-linolenic and stearic acids. This study highlights that the diatom Thalassiosira species are a major source of omega-3 PUFAs, underscoring their considerable value for nutraceutical and pharmaceutical applications.