Chemistry and utilization of plankton - XV. Extractive nitrogenous components of the halotolerant alga Dunaliella bardawil.

Abstract

Extractive nitrogenous constituents in a unicellular green microscopic halotolerant alga Dunaliella bardawil were investigated for the freeze-dried preparation. Total nitrogens of the 70% and 80% ethanolic extracts were determined to be 851mg and 798mg per 100g of the dried alga. The composition of nitrogenous components showed little difference between both extracts and was characterized by being rich in free amino acids, especially in glutamic acid, leucine, alanine, lysine, phenylalanine, valine, threonine, and arginine. Considerable amounts of low molecular peptides were also present. In the nucleotides and related compounds, small amounts of AMP and UMP together with fairly high levels of the corresponding nucleosides, adenosine and uridine, and lower levels of the bases, hypoxanthine and uracil, were detected. CMP was found to be rich but cytidine and cytosine were not present. No ω-betaines were found but homarine was abundant with a small amount of trigonelline. The nitrogen of free amino acids and peptides was equivalent, accounting for approximately 90% of total nitrogen, followed by those of nucleotides and related compounds (7-8%) and betaines (1.5%). The sum total amounted to 95-103% of total nitrogen, indicating that the composition of extractive nitrogenous components of D. bardawil has almost completely been resolved.