Clostridium manihotivorumsp. nov., a novel mesophilic anaerobic bacterium that produces cassava pulp-degrading enzymes

Abstract

BackgroundCassava pulp is a promising starch-based biomasses, which consists of residual starch granules entrapped in plant cell wall containing non-starch polysaccharides, cellulose and hemicellulose. Strain CT4T, a novel mesophilic anaerobic bacterium isolated from soil collected from a cassava pulp landfill, has a strong ability to degrade polysaccharides in cassava pulp. This study explored a rarely described species within the genusClostridiumthat possessed a group of cassava pulp-degrading enzymes.MethodsA novel mesophilic anaerobic bacterium, the strain CT4T, was identified based on phylogenetic, genomic, phenotypic and chemotaxonomic analysis. The complete genome of the strain CT4Twas obtained following whole-genome sequencing, assembly and annotation using both Illumina and Oxford Nanopore Technology (ONT) platforms.ResultsAnalysis based on the 16S rRNA gene sequence indicated that strain CT4Tis a species of genusClostridium. Analysis of the whole-genome average amino acid identity (AAI) of strain CT4Tand the other 665 closely related species of the genusClostridiumrevealed a separated strain CT4Tfrom the others. The results revealed that the genome consisted of a 6.3 Mb circular chromosome with 5,664 protein-coding sequences. Genome analysis result of strain CT4Trevealed that it contained a set of genes encoding amylolytic-, hemicellulolytic-, cellulolytic- and pectinolytic enzymes. A comparative genomic analysis of strain CT4Twith closely related species with available genomic information,C. amylolyticumSW408T, showed that strain CT4Tcontained more genes encoding cassava pulp-degrading enzymes, which comprised a complex mixture of amylolytic-, hemicellulolytic-, cellulolytic- and pectinolytic enzymes. This work presents the potential for saccharification of strain CT4Tin the utilization of cassava pulp. Based on phylogenetic, genomic, phenotypic and chemotaxonomic data, we propose a novel species for which the nameClostridium manihotivorumsp. nov. is suggested, with the type strain CT4T(= TBRC 11758T= NBRC 114534T).