Production of amino acids by the N2-fixing blue-green alga Anabaena variabilis var. kashiensis

Abstract

Summary The production of extracellular, free and combined amino acids by a locally isolated Anabaena variabilis var. kashiensis was investigated. Under conditions of autotrophic nutrition of growth and in absence of combined nitrogen the organism could synthesize fifteen amino acids. Glutamic acid, hydroxyproline, and serine in the combined form were detected in high amounts, while leucine and alanine as well as ornithine, threonine, tryptophane, and proline were found in moderate or in relatively low concentrations. The most predominating free amino acids were lysine, histidine, and glycine. Seven extracellular amino acids could be recovered in the culture filtrate, but in relatively low concentrations. The effect of addition of glucose or sodium nitrate to the culture medium as well as the effect of different levels of hydrogen ion concentration on the synthesis of amino acids was also studied.