Understanding and exploiting biological metal-nanoparticle synthesis for metal recovery

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There is increasing concern over environmental copper levels, their toxicity and their adverse effects on humans and wildlife. The environmental quality standard of copper in groundwater in the UK is set low, at 1-28 ug/l, to balance these risks against the interests of industry. Consequently, the currently allowed environmental level of copper effectively pitches the key Scottish industry of salmon fishing against another - the spirits industry, as whisky, vodka and gin production involve a universal step of distillation in copper pot stills. Soluble copper is required in the distilling process as it prevents sulphur-containing compounds from distilling with the alcohol, which would give it an aroma of bad eggs, so a simple change to the material from which the stills are made is not an option. This dissolved copper is then found in the waste, and not the whisky, in concentrations high enough to be toxic to living organisms. Therefore, it is necessary to treat the waste before it can be used as animal feed, fertiliser or released into the environment.The whisky industry has invested heavily in research to develop an effective method for removing toxic material from the waste of the whisky making process. Current treatments include chemical and physical methods that are expensive and have significant limitations. Cheap and effective treatment methods for copper contaminated waste still need to be developed and employing bacteria for the recycling of such contaminants may provide the solution, allowing the whisky industry to continue its expansion without adverse environmental consequences.The biological transformation of copper ions to stable copper nanoparticles may provide a cost-effective biological solution for the treatment of distillery coproducts. This biotransformation of metal ions occurs naturally within some bacteria with the formation of solid metal nanoparticles outside of the bacterial cell. Our previous work has shown that distillery coproducts are an excellent nutrient source for our chosen bacterium and that the copper ions in distillery coproducts can be biotransformed to nanoparticles at the same time.This application requests funding to improve the efficiency of this process to allow its future use on a industrial scale.