Pseudodesulfovibrio cashewsp. nov., a novel deep-sea sulfate-reducing bacterium, linking heavy metal resistance and sulfur cycle

Sulfur cycling is primarily driven by sulfate reduction mediated by sulfate-reducing bacteria (SRB) in marine sediments. The dissimilatory sulfate reduction drives the production of enormous quantities of reduced sulfide and thereby the formation of highly insoluble metal sulfides in marine sediments. Here, a novel sulfate-reducing bacterium designated Pseudodesulfovibrio cashew SRB007 was isolated and purified from the deep-sea cold seep and proposed to represent a novel species in the genus of Pseudodesulfovibrio.

A detailed description of the phenotypic traits, phylogenetic status and central metabolisms of strain SRB007, allowing the reconstruction of the metabolic potential and lifestyle of a novel member of deep-sea SRB. Notably, P. cashew SRB007 showed a strong ability to resist and remove different heavy metal ions including Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Cd²⁺ and Hg²⁺. And the dissimilatory sulfite reduction was demonstrated to contribute to the prominent removal capability of P. cashew SRB007 against different heavy metals via forming insoluble metal sulfides.

IMPORTANCE The dissimilatory sulfate reduction driven by sulfate-reducing bacteria (SRB) was ubiquitous in marine sediments, and was proposed to couple with heavy metal ions removal through forming insoluble metal sulfides. The deep-sea cold seep is a very special environment where is rich in sulfate and novel species of SRB that possessing many unknown mechanisms toward sulfur cycle.

Here, a novel sulfate-reduction bacterium Pseudodesulfovibrio cashew SRB007 was isolated from the deep-sea cold seep and proposed as the type strain for a novel species. The taxonomy and typical physiological properties closely related to sulfur cycle, heavy metal resistance and their co-relationship were disclosed through a combination of genomic and biochemical methods.

Given the absence of pure cultures of typical SRB isolated from the deep-sea cold seep, our work provides a good model to study the sulfur cycle which coupling with other elements and a potential candidate to develop bioremediation product in the future.