Substrate utilization and secondary metabolite biosynthesis in the phylum Planctomycetota

The phylum Planctomycetota is changing our understanding of bacterial metabolism, driving critical biogeochemical processes through the transformation of complex polymeric substrates into valuable bioactive compounds. Sophisticated methods for cultivation, genome sequencing and genetic strain engineering developed in the last two decades have stimulated detailed studies on cell propagation, metabolic capabilities and potential applications of phylum members beyond the mere isolation and characterization of novel taxa. This review synthesizes recent advances in understanding the Planctomycetota physiology with a focus on the degradation of phototroph-derived polysaccharides, anaerobic ammonium oxidation (anammox) and biosynthesis of secondary metabolites. New data especially collected over the last 5 years justifies more intensive research of the yet uncharacterized pathways of substrate uptake and utilization, as well as genome mining-assisted bioprospection to exploit the phylum's chemical repertoire. KEY POINTS: • Planctomycetes can degrade high-molecular-weight sugars produced by algae • Anaerobic ammonium oxidation (anammox) is used in technical applications • The first secondary metabolites were discovered in the last 5 years.