Alienimonas Californiensis Gen. Nov. Sp. Nov., a Novel Planctomycete Isolated from the Kelp Forest in Monterey Bay

Planctomycetes are environmentally and biotechnologically important bacteria and are often found in association with nutrient-rich (marine) surfaces. To allow a more comprehensive understanding of planctomycetal lifestyle and physiology we aimed at expanding the collection of axenic cultures with new isolates. Here, we describe the isolation and genomic and physiological characterisation of strain CA12 obtained from giant bladder kelp (Macrocystis pyrifera) in Monterey Bay, California, USA. 16S rRNA gene sequence and whole genome-based phylogenetic analysis showed that strain CA12 clusters within the family Planctomycetaceae and that it has a high 16S rRNA sequence similarity (82.3%) to Planctomicrobium piriforme DSM 26348. The genome of strain CA12 has a length of 5,475,215 bp and a G+C content of 70.1%. The highest growth rates were observed at 27 °C and pH 7.5. Using different microscopic methods, we could show that CA12 is able to divide by consecutive polar budding, without completing a characteristic planctomycetal lifestyle switch. Based on our data, we suggest that the isolated strain represents a novel species within a novel genus. We thus propose the name Alienimonas gen. nov. with Alienimonas californiensis sp. nov. as type species of the novel genus and CA12 as type strain of the novel species.