Starch in prasinophycean algae

Reserve products isolated from three species of prasinophycean algae: Pyramimonas parkeae Norris and Pearson, Pyramimonas amylifera Conrad and Platymonas tetrathele West were compared. Three pieces of experimental evidence indicate that the reserve product of each of the species analyzed is a true starch. (I) There is no essential difference between the light absorption curve for the complex formed between corn starch and iodine and the corresponding curves for the algal products. (2) The β-amylase breakdown limit of these compounds is very close to that of corn starch. (3) The X-ray diffraction diagrams produced by the reserve material from Pyramimonas parkeae and Platymonas tetrathele is a so-called A-spectrum characteristic of cereal starches while the diagram produced by grains from Pyramimonas amylifera corresponds to the B-spectrum typical for tuber starches. The dissimilarity between the X-ray diagrams produced by the starches from the Pyramimonas species suggests that a re-examination of the taxonomy of these species is warranted.