Leviathan: A fast, memory-efficient, and scalable taxonomic and pathway profiler for next generation sequencing (pan)genome-resolved metagenomics and metatranscriptomics

Metagenomic and metatranscriptomic functional profiling is crucial for understanding microbial community capabilities, yet current tools often face challenges in computational efficiency, scalability, and integrated genome-resolved references. Here, I introduce Leviathan, an open-source software package designed to address these limitations. Leviathan implements taxonomic profiling via Sylph and a novel highly optimized functional profiling workflow. The functional profiling workflow uniquely combines the speed of PyHMMER for feature annotation, the accuracy of Salmon for read quantification against genome-resolved reference gene catalogs, and graph-based pathway completeness assessment. I demonstrate Leviathans capabilities using the CAMI low, medium, and high complexity datasets. Compared to the widely used tool HUMAnN, Leviathan exhibits significantly reduced runtimes (up to ~72-fold faster) and memory usage (up to ~14-fold lower), while achieving competitive or superior accuracy gains (up to 12%) in identifying functional features at both individual genome and pangenome levels. Notably, Leviathan natively supports and streamlines pangenome-level analysis, a critical aspect for understanding functional redundancy and diversity within microbial communities. Leviathan is available as an open-source software package offering a powerful and accessible solution for comprehensive genome-resolved metagenomic profiling.