HighlightsThe individual components of the biodiesel had a lower toxicity threshold than in the complex mixture.The B20 sample proved to be the most toxic for the red algae P. purpureum.The B100 sample showed the highest level of toxicity for the microalgae A. ussuriensis, C. muelleri and H. akashiwo.The sample of petroleum diesel B0 showed less toxicity compared to B20 and B100.