Proteogenomic analysis of Georgfuchsia toluolica revealed unexpected concurrent aerobic and anaerobic toluene degradation

Siavash Atashgahi (1, 2, 3) , Margreet J Oosterkamp (1, 4) , Peng Peng (1, 5) , Jeroen Frank (2, 3) , Beate Kraft (6) , Bastian Hornung (7, 1) , David Schleheck (8) , Sebastian Lücker (2) , Mike S M Jetten (2, 3) , Alfons J M Stams (1, 3) , Hauke Smidt (1)

1 WUR - Wageningen University and Research [Wageningen]
2 Radboud University [Nijmegen]
3 Soehngen Institute of Anaerobic Microbiology
4 Sub-department of Environmental Technology
5 CEE - Department of Civil and Environmental Engineering [Ann Arbor]
6 NORDCEE - Nordic Centre of Earth Evolution
7 AFMB - Architecture et fonction des macromolécules biologiques
8 University of Konstanz

Denitrifying Betaproteobacteria play a key role in the anaerobic degradation of monoaromatic hydrocarbons. We performed a multi‐omics study to better understand the metabolism of the representative organism Georgfuchsia toluolica strain G5G6 known as a strict anaerobe coupling toluene oxidation with dissimilatory nitrate and Fe(III) reduction. Despite the genomic potential for degradation of different carbon sources, we did not find sugar or organic acid transporters, in line with the inability of strain G5G6 to use these substrates. Using a proteomics analysis, we detected proteins of fumarate‐dependent toluene activation, membrane‐bound nitrate reductase, and key components of the metal‐reducing (Mtr) pathway under both nitrate‐ and Fe(III)‐reducing conditions. High abundance of the multiheme cytochrome MtrC implied that a porin–cytochrome complex was used for respiratory Fe(III) reduction. Remarkably, strain G5G6 contains a full set of genes for aerobic toluene degradation, and we detected enzymes of aerobic toluene degradation under both nitrate‐ and Fe(III)‐reducing conditions. We further detected an ATP‐dependent benzoyl‐CoA reductase, reactive oxygen species detoxification proteins, and cytochrome c oxidase indicating a facultative anaerobic lifestyle of strain G5G6. Correspondingly, we found diffusion through the septa a substantial source of oxygen in the cultures enabling concurrent aerobic and anaerobic toluene degradation by strain G5G6.

Domains: Life Sciences [q-bio]; Environmental Sciences; Microbiology and Parasitology

Siavash Atashgahi, Margreet J Oosterkamp, Peng Peng, Jeroen Frank, Beate Kraft, et al.. Proteogenomic analysis of Georgfuchsia toluolica revealed unexpected concurrent aerobic and anaerobic toluene degradation. Environmental Microbiology Reports, 2021, 13 (6), pp.841-851. ⟨10.1111/1758-2229.12996⟩. ⟨hal-04543783⟩