Comparison of suitable protein measurement forThalassiosira weissflogii(Bacillariophyta) andTetraselmis chuii(Chlorophyta)

SUMMARY To perform effective measurement of the protein contents, it is necessary to apply the most suitable extraction technique. We compared protein extraction techniques for two microalgal species with entirely different cell wall structures, such as diatom Thalassiosira weissflogii and green flagellate Tetraselmis chuii, using mechanical, physical, and chemical extraction methods. Our results showed that in Th. weissflogii, the control treatment without extraction and mechanical disruption using ultrasonication was sufficient to disrupt its brittle cell wall, resulting in the protein yield of 19.03 and 19.46% of dry weight (DW), respectively. In case of Te. chuii, the chemical extraction using 6% trichloroacetic acid at 95°C was the most suitable extraction method, resulting in the protein yield of 23.78% of DW. Therefore, the most suitable extraction technique must be individually selected for each species depending on their cell wall properties.