“…Mean NPN concentrations were 70, 86, 47 and 110 g/kg DM, which equals 10%, 16%, 11% and 25% of CP for Arthrospira , Chlorella , Nannochloropsis and Phaeodactylum respectively. Among others, NPN compounds in microalgae can be free AA (Al‐Amoudi & Flynn, ; Dortch, Clayton, Thoresen, & Ahmed, ; Flynn, Garrido, Zapata, Öpik, & Hipkin, ), nucleic acids (Dortch et al., ; Lourenço, Barbarino, Marquez, & Aidar, ; Lourenço et al., ) and nitrogenous pigments, such as chlorophylls (Lourenço et al., , ). Furthermore, NPN compounds can originate from intracellular inorganic nitrogenous compounds, such as nitrate, nitrite and ammonium (Dortch, ; Dortch et al., ; Lourenço et al., , ).…”