ecmtool: fast and memory-efficient enumeration of elementary conversion modes

21.03.2023

An update to ecmtool that uses mplrs for parallelized ECM enumeration: Bianca Buchner, Tom J. Clement, Daan H. de Groot, and Jürgen Zanghellini

Published in Bioinformatics, 39, 3. March 2023, btad095.

doi.org/10.1093/bioinformatics/btad095

Motivation: Characterizing all steady-state flux distributions in metabolic models remains limited to small models due to the explosion of possibilities. Often it is sufficient to look only at all possible overall conversions a cell can catalyze ignoring the details of intracellular metabolism. Such a characterization is achieved by elementary conversion modes (ECMs), which can be conveniently computed with ecmtool. However, currently, ecmtool is memory intensive, and it cannot be aided appreciably by parallelization.

Results: We integrate mplrs - a scalable parallel vertex enumeration method - into ecmtool. This speeds up computation, drastically reduces memory requirements and enables ecmtool's use in standard and high-performance computing environments. We show the new capabilities by enumerating all feasible ECMs of the near-complete metabolic model of the minimal cell JCVI-syn3.0. Despite the cell's minimal character, the model gives rise to 4.2×109 ECMs and still contains several redundant sub-networks.

Run time of ecmtool.

(a) Run time and (b) memory consumption of ecmtool using mplrs (squares) or polco (circles) as a function of the number of excess nutrients in the minimal medium of JCVI-syn3A. Empty and full symbols indicate VE1 and VE2. (c) Structogram of ecmtool.