Anton Bruckner has published five different versions of Tantum Ergo whose general structures are similar (homophony of voices, identical breathing of the text ...).
The first four are with 4 mixed voices and the fifth (in D) is with five mixed voices. Bruckner offers organ accompaniment that doubles the voices. This music with an assertive romantic expression is powerful and harmonically very fine. It is to be discovered.
A four-voices version (in Eb) is available here too: Mef 840