Interactions between Marinobacter atlanticus and heavy metals.

Marine bacteria have evolved mechanisms for the regulation of essential heavy metal ions (e.g., copper, zinc, and cobalt). Understanding the interplay between these ions and marine bacteria is relevant to a variety of applications, including the development of antifouling coatings and materials and the capture and sensing of metal ions in seawater. Here, we investigate the interactions between Marinobacter atlanticus and heavy metals commonly found in natural environments at trace levels. Furthermore, M. atlanticus can produce small amounts of electricity and this ability is affected by labile metal ion concentration and can influence mineral cycling. We hypothesized that M. atlanticus may be a promising candidate for applications in heavy metal remediation or as a biosensor for heavy metal contamination. We utilized broth microdilution assays to expose M. atlanticus to a concentration range of essential and nonessential metal ions. M. atlanticus demonstrated a profound ability to grow in the presence of metal concentrations that significantly exceed those found in native environments. In metal depletion assays, where the ability of M. atlanticus to remove metal ions from solution was assessed, we found that this bacterium exhibited a marginal ability to reduce metal concentrations, with cadmium being the only heavy metal whose uptake significantly increased throughout a 72 h evaluation period. Our results suggest M. atlanticus has limited use for bioremediation but could potentially be used for biosensing.