Comparative genomic analysis ofPlanctomycetotapotential towards complex polysaccharide degradation identifies phylogenetically distinct groups of biotechnologically relevant microbes

Abstract

ABSTRACTThe outstanding hydrolytic potential of thePlanctomycetotaphylum for complex polysaccharide degradation has recently been acknowledged based on the numerous carbohydrate-active enzymes (CAZymes) encoded in their genomes. However, mainly members of thePlanctomycetiaclass have been characterised up to now, and little is known about the degrading capacities of the otherPlanctomycetota. Our in-depth characterisation of the available planctomycetotal genomic resources increased our knowledge of the carbohydrolytic capacities ofPlanctomycetota. We showed that this single phylum encompasses a wide variety of the currently known CAZyme diversity assigned to glycoside hydrolase families, and that many members are characterised by a high versatility towards complex carbohydrate degradation, including lignocellulose. We also highlighted members of theIsosphaerales, Pirellulales, SedimentisphaeralesandTepidisphaeralesorders as having the highest encoded hydrolytic potential of thePlanctomycetota. Furthermore, members of a yet uncultivated group affiliated toPhycisphaeraleswere identified as an interesting source of novel, lytic polysaccharide monooxygenases that could boost lignocellulose degradation. Surprisingly, manyPlanctomycetotafrom anaerobic digestion reactors were shown to encode CAZymes targeting algal polysaccharides – this opens new perspectives for algal biomass valorisation in biogas processes. Our study provides a new perspective on planctomycetotal carbohydrolytic potential, highlighting distinct phylogenetic groups which could provide a wealth of diverse, potentially novel CAZymes of industrial interest.