Shotgun proteomic analysis of nanoparticle-synthesizing Desulfovibrio alaskensis in response to platinum and palladium

Michael J Capeness,Louise E Horsfall,Lukas F Mühlbauer,Lisa Imrie,Thierry Le Bihan

doi:10.1099/mic.0.000840

Michael J Capeness, Louise E Horsfall + Show 3 more

Open Access

https://doi.org/10.1099/mic.0.000840

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Abstract

Platinum and palladium are much sought-after metals of critical global importance in terms of abundance and availability. At the nano-scale these metals are of even higher value due to their catalytic abilities for industrial applications. Desulfovibrio alaskensis is able to capture ionic forms of both of these metals, reduce them and synthesize elemental nanoparticles. Despite this ability, very little is known about the biological pathways involved in the formation of these nanoparticles. Proteomic analysis of D. alaskensis in response to platinum and palladium has highlighted those proteins involved in both the reductive pathways and the wider stress-response system. A core set of 13 proteins was found in both treatments and consisted of proteins involved in metal transport and reduction. There were also seven proteins that were specific to either platinum or palladium. Overexpression of one of these platinum-specific genes, a NiFe hydrogenase small subunit (Dde_2137), resulted in the formation of larger nanoparticles. This study improves our understanding of the pathways involved in the metal resistance mechanism of Desulfovibrio and is informative regarding how we can tailor the bacterium for nanoparticle production, enhancing its application as a bioremediation tool and as a way to capture contaminant metals from the environment.

Highlights

There is an increasing demand for expensive platinum- group metals
Despite the fact that D. alaskensis has been used for metal ion bioremediation for some years, this paper, to the best of our knowledge, presents the first shotgun proteomic analysis of bacteria synthesizing palladium and platinum nanoparticles
Various strains of Desulfovibrio were used for these previous studies, only a few of the proteins reported here have previously been implicated in metal reduction and nanoparticle production

Summary

Introduction

There is an increasing demand for expensive platinum- group metals. Amongst other applications, they are used for automotive catalytic converters from which platinum and palladium escape via the exhaust, making them a source of environmental pollution [1]. Prokaryotes have been used to remediate metal ions from solution for decades: mostly high value metals such as gold, platinum and silver have been targeted [2, 3]

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