Zixibacteria is a bacterial phylum with candidate status, meaning it had no cultured representatives. It is a member of the FCB group Zixibacteria was proposed as a bacterial phylum following the recovery of a genome from representative RBG-1. This genome was recovered using genome-resolved metagenomics from sediment samples of an aquifer adjacent to the Colorado River (CO, USA) and was suggestive of metabolically versatility, which is presumably requisite for life in a rapidly changing environment such as aquifer sediments