Many, if not all, retinalophototrophs are photoheterotrophs: although sufficient ATP is produced by light, they cannot subsist on light and inorganic substances alone because they cannot produce needed organic materials from only . This category includes retinalophototrophs that perform anaplerotic fixation, such as a flavobacterium that can use pyruvate and CO to make malate. This ability does, however, help "stretch" limited supplies of carbon.