Prochlorobacteria is different from Bacteria because they possess both chlorophylls a and b of higher plants. The prochlorobacteria also produce oxygen like the Cyanophyta, but unlike cyanobacteria they do not have phycobilin pigments.
Prochlorobacteria is a phylum under the Kingdom Bacteria in the six kingdom system. There are only a few known species, and it is believed that they are related to the chloroplasts in organisms. They have chlorophyll, the only bacteria to have this.