[1] In 1897, he began teaching physiology at the University of Berlin, where he also became the editor of the Archiv für Anatomie und Physiologie.

[2] Engelmann's major contribution to the field of physiology emerged from a study lasting from 1873 to 1897, in which he observed the contractions of striated muscles.

Engelmann performed three significant experiments involving photosynthesis: In 1881, he observed the movement of bacteria towards the chloroplasts in a strand of Spirogyra algae.

Engelmann hypothesized that the bacteria were moving in response to oxygen generated by the photosynthetically active chloroplasts in the algae.

[5] Moreover, he was among the first scientists who traced a relationship between the availability of wavelengths in underwater light (which are changing/decreasing with depth) and the occurrence of those phototrophs which can efficiently absorb and use them.