Rhodoluna is a Gram-positive, non-spore-forming and non-motile genus of bacteria from the family of Microbacteriaceae.[1] The type strain of the only species Rhodoluna lacicola encodes an actinorhodopsin, which is a light-diven proton pump enabling light energy conversion,[2] potentially resulting in a mixotrophic physiology. The type strain of R. lacicola was isolated from Lake Tai (Lake Taihu) in China. The type strain MWH-Ta8 is remarkable for its very small cell size ultramicrobacterium and its small genome size of only 1.4 Mbp. The type strain has a planktonic lifestyle, that is freely floating the water column of aquatic systems.Currently, the genus Rhodoluna contains two described species (R. lacicola and R. limnophila[3]).