Bacterial diversity and metabolism in microbial consortium of non-axenic culture Tychonema sp. BBK16

Abstract

We performed high-throughput sequencing of microbial community with cyanobacterium Tychonema sp. BBK16 and heterotrophic bacteria in vitro. Representatives of the phylum Pseudomonadota/Proteobacteria, the bacteria Hydrogenophaga, Sphingomonas, Paucibacter, Aminobacter, Devosia, Tahibacter, and Bosea dominate and coexist with the cyanobacterium for a long period of cultivation. It was found that this cyanobacterium is an edificator of this community providing the microbiome with organic matter. Metabolic features of heterotrophic bacteria based on reconstructed genomes are presented. The main processes of carbon and nitrogen metabolism in the biofilm are carbohydrate and amino acid metabolism, as well as processes regulating the relationships between members of this consortium. Hydrogenophaga sp. and Tychonema sp. BBK16 show carbon autotrophy due to the Calvin–Benson–Bassham (СВВ) cycle, while Sphingomonas sp. due to the glyoxylate pathway of metabolism. The biofilm also contains the anoxygenic photoheterotroph Bosea sp. using light energy to transform organic matter. Aminobacter sp. is an active degrader of complex organics, which possesses methylotrophy and supplies hydrogen for oxidation by Hydrogenophaga sp., Paucibacter sp., also supplies hydrogen for this community. Sphingomonas, Tychonema and Paucibacter release phosphate from organic compounds providing phosphorus to this consortium.