Alkenones are unique lipids produced by certain species
of microalgae,
well-known for use in paleoclimatology, and more recently pursued
to advance sustainability across multiple industries. Beginning in
2018, the biosynthesis of alkenones by commercially grown Tisochrysis lutea (T-Iso) microalgae from one of the world’s most established producers,
Necton S.A., changed dramatically from structures containing 37 and
38 carbons, to unusual shorter-chain C35 and C36 diunsaturated alkenones
(C35:2 and C36:2 alkenones). While the exact reasons for this change
remain unknown, analysis of alkenones isolated from T-Iso grown in 2021 and 2023 revealed that this change has persisted.
The structure of these rare shorter-chain alkenones, including double
bond position, produced by Necton T-Iso remained
the same over the last five years, which was determined using a new
and optimized cross-metathesis derivatization approach with analysis
by comprehensive two-dimensional gas chromatography and NMR. However,
noticeable differences in the alkenone profiles among the different
batches were observed. Combined with fatty acid compositional analysis,
the data suggest a connection between these lipid classes (e.g., increased DHA corresponds to lower amounts of shorter-chain
alkenones) and the ability to manipulate their biosynthesis in T-Iso with changes to cultivation conditions.