Melainabacteria have been found to potentially play a role in digesting fiber in the human gut, and are more commonly in herbivorous mammals and those with plant-rich diets. Because plant diets require more fiber break-down, Melainabacteria may aid in this digestive function. However, scientists are unsure of why these microbes are in the gut and how they got there. Ongoing studies such as, "The human gut and groundwater harbor non-photosynthetic bacteria belonging to a new candidate phylum sibling to Cyanobacteria," funded by various organizations such as the National Institutes of Health, the David and Lucile Packard Foundation, The Hartwell Foundation, the Arnold and Mabel Beckman Foundation, the U.S. Department of Energy, the European Molecular Biology Organization and the Wellcome Trust.