Photosynthesis, in general, is accompained by the release of oxygen. Prokaryotes are exception to it as a typical bacterial photosynthesis is anoxygenic (oxygen is not released). However, cyanobacteria is an exception to the bacterial photosynthesis as it is oxygenic.
Source of oxygen in photosynthesis is photolysis of water. Photolysis is associated with PSII. ...
Bacterial photosynthesis except cyanobacteria is anoxygenic. Oxygenic photosynthesis is linked to PSII which is absent in a typical bacteria.