A novel bacterial thiosulfate oxidation pathway provides a new clue about the formation of zero-valent sulfur in deep sea

Abstract

Zero-valent sulfur (ZVS) has been shown to be a major sulfur intermediate in the deep-sea cold seep of the South China Sea based on our previous work, however, the microbial contribution to the formation of ZVS in cold seep has remained unclear. Here, we describe a novel thiosulfate oxidation pathway discovered in the deep-sea cold seep bacterium Erythrobacter flavus 21–3, which provides a new clue about the formation of ZVS. Electronic microscopy, energy-dispersive, and Raman spectra were used to confirm that E. flavus 21–3 effectively converts thiosulfate to ZVS. We next used a combined proteomic and genetic method to identify thiosulfate dehydrogenase (TsdA) and thiosulfohydrolase (SoxB) playing key roles in the conversion of thiosulfate to ZVS. Stoichiometric results of different sulfur intermediates further clarify the function of TsdA in converting thiosulfate to tetrathionate ( − O 3 S–S–S–SO 3 − ), SoxB in liberating sulfone from tetrathionate to form ZVS and sulfur dioxygenases (SdoA/SdoB) in oxidizing ZVS to sulfite under some conditions. Notably, homologs of TsdA, SoxB, and SdoA/SdoB widely exist across the bacteria including in Erythrobacter species derived from different environments. This strongly indicates that this novel thiosulfate oxidation pathway might be frequently used by microbes and plays an important role in the biogeochemical sulfur cycle in nature.

Characterization of the first cultured free-living representative of Candidatus Izimaplasma uncovers its unique biology

“…Notably, thiosulfate also promotes the saccharides metabolism and thereby benefiting the bacterial growth (Fig. 3), which endows X. coldseepsis zrk13 a better adaptability to the deep-sea environment given ubiquitous existence of thiosulfate in the cold seep 21 . Therefore, we believe saccharide metabolism is crucial for maintaining the growth of X. coldseepsis zrk13 both in the laboratorial and deep-sea environments.…”

“…X. coldseepsis zrk13 was isolated from a deep-sea cold seep, and different sulfur sources were detected to ubiquitously exist in the environment in our previous study 21 .…”

“…The deep-sea samples were collected by RV KEXUE from a typical cold seep in the South China Sea (E119º 17'07.322'', N22º 06'58.598'') as described previously21 . To understand the abundance of Tenericutes in deep-sea cold (which was not certified by peer review) is the author/funder.…”

A marine bacterial community that degrades poly(ethylene terephthalate) and polyethylene

“…Ochrobactrum sp, which were further incubated and performed genomic sequencing as described previously 51 . Sequencing libraries were generated using NEBNext® Ultra™ DNA Library Prep Kit for Illumina (NEB, USA) following manufacturer's recommendations and index codes were added to attribute sequences to each sample 52 .…”

Cultivation and characterization of a novel clade of deep-sea Chloroflexi: providing a glimpse of the phylum Chloroflexi involved in sulfur cycling

“…nov.. The cycling of sulfur is a dominant metabolism pathway for the marine subsurface microorganisms [26,65], and deep-sea Chloroflexi bacteria were predicted to respire oxidized sulfur compounds [4] and metabolize multiple organosulfur compounds [28] based on metagenomics data. However, to date, no studies based on the pure culture have verified that Chloroflexi members indeed drive sulfur cycling of deep-sea environments.…”