Single-celled marine protists belonging to the genus Thraustochytrium (class Labyrinthulomycetes) are of biotechnological interest due to their high production of polyunsaturated fatty acids (PUFAs). They produce particularly high amounts of omega-3 PUFAs making them an attractive source of omega-3 PUFAs as opposed to oil sourced from fish. Preliminary genomic information, laboratory growth on various carbon sources, effect on diatom (Cyclotella cryptica) growth in co-culture, and ultrastructural characteristics of the marine protist Thraustochytrium sp. LLF1b is presented in this work.