The estimation of micro-algal protein content and its meaning to the evaluation of algal biomass I. Comparison of methods for extracting protein

The spectrophotometric evaluation of micro-algal protein needs a prior extraction from cells in order to liberate protein for measurement. The conditions of extraction (temperature, duration, normality of sodium hydroxide, pretreatment) which yield optimal protein content are tested with three algal cultures (Scenedesmus, Synechococcus, Asterionella). A standard method of extraction is presented. Comparison of this method with nine published methods reveals markedly lower protein yields for easy extractable (43–100%) and hard extractable (5–75%) algal species, relative to this method, depending on ease of cell wall breakage. The application of this standard method to field investigations is demonstrated and compared to other biochemical parameters. The advantages of this method over other protein extraction methods, with respect to field material, are discussed.