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Research article2025Peer reviewed

Identifying Bacteria Responsible for Non-Sulphate-Based Hydrogen Sulphide Production in Aquaculture

Nguyen-tiet, Alexandre; Puente-Sanchez, Fernando; Bertilsson, Stefan; Aalto, Sanni L.

Abstract

The unintended microbiological production of hydrogen sulphide (H2S) poses a significant challenge in engineered systems, including sewage treatment plants, landfills and aquaculture systems. Although sulphur-rich amino acids and other substrates conducive to non-sulphate-based H2S production are frequently present, the capacity and potential of various microorganisms to perform sulphate-free H2S production remain unclear. In this study, we identify the identity, activity and genomic characteristics of bacteria that degrade cysteine to produce H2S in anaerobic enrichment bioreactors seeded with material from aquaculture systems. Our comparison with canonical sulphate-reducing bacteria reveals that both sulphur sources contribute to microbial H2S production, with cysteine facilitating a more rapid process compared to sulphate. 16S rRNA amplicon sequencing and metagenomic analysis identified four bacterial families-Dethiosulfatibacteraceae, Fusobacteriaceae, Vibrionaceae and Desulfovibrionaceae-as central to non-sulphate H2S production. Metagenome- and metatranscriptome-assembled genomes elucidated the primary cysteine degradation pathway mediated by cysteine desulphidase cyuA and indicated that some bacteria may also utilise cysteine as a carbon source in sulphate-based H2S production.

Keywords

amino acid fermentation; cysteine desulphidase; cyuA; hydrogen sulphide; yhaM

Published in

Environmental Microbiology
2025, volume: 27, number: 1, article number: e70024
Publisher: WILEY

SLU Authors

UKÄ Subject classification

Microbiology

Publication identifier

  • DOI: https://doi.org/10.1111/1462-2920.70024

Permanent link to this page (URI)

https://res.slu.se/id/publ/140202