Isolation of highly copper-resistant bacteria from deep-sea hydrothermal fields and description of a novel species sp. nov.

INTRODUCTION

Hydrothermal vents, rich in heavy metals, provided a unique niche for heavy metal resistant microbes. However, knowledge about copper resistant microbes in deep sea hydrothermal vents is still limited.

METHODS

The copper-resistant bacteria were isolated from deep-sea hydrothermal vent samples and conducted thorough physical, phylogenetic, and genomic analyses to elucidate their copper resistance capability and related genes.

RESULTS

Twelve highly copper-resistant bacteria (up to 6-10 mM) were isolated from deep sea hydrothermal fields They were affiliated with the (4), (3), (2), (1), and (1) genus in the α-Proteobacteria, and the (1) genus in the β-Proteobacteria. The presence of copper in the medium obviously induced the amount of polysaccharides and proteins in the crude extracellular polymeric substances (EPS) produced by sp. CuT 3-1, sp. CuT 4-3 and CuT 6, which could absorb 40 to 50 mg•g copper. We further described a novel species, sp. nov. CuT 6, which exhibited a higher copper resistance and encoded more heavy metal resistance-related genes than other Marinobacter species.

DISCUSSION

It revealed that the copper resistance capability exhibited by these strains in hydrothermal fields is likely attributed to the production of exopolymeric substances, such as polysaccharides and proteins, as well as active transport or efflux mechanisms for heavy metals.