show Abstracthide AbstractIn a previous BioProject (PRJNA640240), we included metagenome data for enrichment cultures of a highly novel bacterial phototroph, "Candidatus Chlorohelix allophototropha" strain L227-S17. This current BioProject is a companion / follow-up project to that work. Here, we combine newly generated long read (Nanopore) sequencing data with previous short read sequencing data (from PRJNA640240) to obtain a closed circular genome bin of Geothrix strain L227-G1, a co-enriched strain in the enrichment culture. After multiple rounds of enrichment cultivation, Geothrix strain L227-G1 came to be the dominant partner strain in the enrichment culture to "Ca. Chx. allophototropha". The high relative abundance of strain L227-G1 in the culture motivated us to characterize this strain's genome in more detail, because such detailed characterization could allow us to better understand the overall properties of the culture.