Bacteria gold
The study of gold-forming bacteria can improve the use and understanding of the item itself. Element coveted and admired since the beginning of civilization, gold has not only been the subject of desire throughout history for its scarcity or uniqueness, but also for their physical and chemical properties: its great malleability, lightness, high electrical conductivity or high resistance to corrosion and humidity are features that have earned over the years role in various facets of the industry, so the presence of the golden element is no longer limited to the coinage of coins and jewelry.
The Gold Rush:
Used in communications, space engineering, photography, microscopy, satellite, medical treatment or even more recently in facial creams and haute cuisine, this great range of possibilities and uses of gold has increased demand and need in many fields, so that improvements in search and obtaining and refinement of processes to understand its properties have experienced a boost in recent years.
The result of this interest in the chemistry of gold and always thinking about the practical advantages of understanding, many research teams have turned their eyes to the nature and the study of microscopic organisms that also use the element gold: the bacteria.
The most recent study published in this field, the work of the team of Frank Reith (University of Adelaide, Australia) In 2010, trying to find out how the bacteria that live on the gold live with him at the metabolic level, and how its dynamics may affect the actual metal. According to the actual Reith, the presence of two populations Cupriavidus metallidurans (One of the bacteria studied) as far apart implied a close relationship between organisms and their gold substrate, so further investigation of the processes of their relationship seemed interesting.
The experiments carried out allowed to observe how these gold deposits accumulate bacteria that are toxic to them, themselves inducing oxidative stress leading to cellular processes that end up isolating active in extracellular nanoparticles, metal. This microscopic particles expelled to the outside has been linked to the “processes of movement / migration” observed in the wild, in which the element appeared to move through the ground. Similarly, the aggregation of these particles could be related to bacterial formation of gold nuggets.
Bacterial sensors:
This new approach to cellular processes can help the researchers, the development of more specific and accurate biosensors to search for new deposits gold. To carry out this crucial step, researchers need to characterize all the genetic and proteomic background behind the processes of aggregation and precipitation of metal. “Effective funding for this purpose, I think we can produce a viable biosensor within 3 to 5 years”, Says Reith.
Other sensors for the same purpose have been tested in other bacteria as Salmonella typhimurium. This bacterium has a system that gives a high resistance to the toxic effects of gold thanks to a transcriptional regulator of high selectivity for this item. In study conducted by S. Cerminati et al. in 2011 Biotechnology and BioengineeringThe research team uses these properties to create a genetic altered strain Escherichia coli can be used as a biosensor.
Small factories gold:
But the Australian research team has not been the first to measure the cellular processes of bacteria aggregating gold. In 2007, a Chinese researchers Shiying led by He, characterized conditions for the biosynthesis of gold particles of bacteria Rhodopseudomonas capsulata. The study, in which the bacteria were suspended in a solution of HAuCl4 at different concentrations, was to better control the production of gold nanoparticles due to the importance of their shape and optical properties in small-scale uses in the laboratory. The study finally concluded that the decisive parameter for controlling the shape and size of the particles was pH to that provided the solution.
