Difference between revisions of "Team:Aix-Marseille/Integrated Practices/Process"
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==Bioleaching== | ==Bioleaching== | ||
| − | The | + | The [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|Bioleaching]] process allow a far better recovery of platinum. Indeed, the drop of pH is required for the metals solubilization. This step could be realized with chemicals as chlorhydric acid in the actual industry. But in order to achieve a greener process as possible, we decided to lower the pH with biological ways, as the leaching accomplished by ''Thiobacillus''. This method is widely use in mines, e.g. for copper mines in South America, so this will be a reliable step already tested in industrial conditions. |
This method rely on the ability of the bacteria ''Thiobacilus'' to acidify its medium until a pH of 1. The bacterium solution is applied on the ashes and liquid part dropping from it constitute the leachate i.e. a very acidified solutions containing solubilized metals particles mostly in ionic form. | This method rely on the ability of the bacteria ''Thiobacilus'' to acidify its medium until a pH of 1. The bacterium solution is applied on the ashes and liquid part dropping from it constitute the leachate i.e. a very acidified solutions containing solubilized metals particles mostly in ionic form. | ||
This step wouldn't be obligatory in our process, but it could improve our recovery yield while still using a environmentally friendly approach. | This step wouldn't be obligatory in our process, but it could improve our recovery yield while still using a environmentally friendly approach. | ||
| − | == | + | ==Siderophore mediated recovery== |
Once the platinum is leached, we need to recover it. If leaching (by biological or chemical methods) is clearly recommended to improves solubilization of metals, it does not improves the concentrations. As we worked with synthetic biology, we decided to use what it is commonly employed by cells to catch metals, i.e. siderophore. Siderophores are well known to catch iron most of all but some of them have an affinity with others metals as platinum. So in our process, we planned to work with such a siderophore, called [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|Desferrioxamine B]]. This one is already employed to recover platinum in mines, and have shown high capacity to recover platinum from ores <ref>Bau and al., 2015 http://dx.doi.org.gate1.inist.fr/10.1016/j.hydromet.2015.01.002</ref>. | Once the platinum is leached, we need to recover it. If leaching (by biological or chemical methods) is clearly recommended to improves solubilization of metals, it does not improves the concentrations. As we worked with synthetic biology, we decided to use what it is commonly employed by cells to catch metals, i.e. siderophore. Siderophores are well known to catch iron most of all but some of them have an affinity with others metals as platinum. So in our process, we planned to work with such a siderophore, called [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|Desferrioxamine B]]. This one is already employed to recover platinum in mines, and have shown high capacity to recover platinum from ores <ref>Bau and al., 2015 http://dx.doi.org.gate1.inist.fr/10.1016/j.hydromet.2015.01.002</ref>. | ||
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[[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|DFHOB]] is a derivative of diamines moelcule and therefore its [[Team:Aix-Marseille/Experiments|Biosynthesis]] start with a amino acid, lysine. Lysine is quite expansive, and as we are aware about the cost of our process we decided to use a cheap source of lysine the [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|corn steep liquor]]. Such a lysine source is already in use in industry since it's cheap, amino acid provided, produced in industrial amounts and well known as a excellent source of nitrogen in growth media. So in this step we hope we could produce [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|DFHOB]] in high quantities with a affordable cost. | [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|DFHOB]] is a derivative of diamines moelcule and therefore its [[Team:Aix-Marseille/Experiments|Biosynthesis]] start with a amino acid, lysine. Lysine is quite expansive, and as we are aware about the cost of our process we decided to use a cheap source of lysine the [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|corn steep liquor]]. Such a lysine source is already in use in industry since it's cheap, amino acid provided, produced in industrial amounts and well known as a excellent source of nitrogen in growth media. So in this step we hope we could produce [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|DFHOB]] in high quantities with a affordable cost. | ||
| − | Following previous uses of [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|DFHOB]], 75% of platinum can be recovered with 3mM [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|DFHOB]] solution on 100g at 5ppm platinum concentrated ore. That allow us to estimate that in order to reach a 75% yield (max yield obtained) we 'll need to add approximately '''3mg of | + | Following previous uses of [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|DFHOB]], 75% of platinum can be recovered with 3mM [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|DFHOB]] solution on 100g at 5ppm platinum concentrated ore. That allow us to estimate that in order to reach a 75% yield (max yield obtained) we 'll need to add approximately '''3mg of DFHOB per µg of platinum'''(see [[Team:Aix-Marseille/Integrated_Practices/Process#Raw calculations|Raw calculations]]). |
| + | |||
| + | '''To sum up, this step consist in adding an appropriated quantity of Siderophore producer E. coli to the leachate.''' | ||
| + | For instance....; CALCULS POUR 1G COMBIEN PRODUIT UNE ECOLI DE DFHOB,,??? | ||
| + | ==Siderophore producer lysis== | ||
| + | Our engineered E. coli, i.e. our siderophore producer will produce a lot of [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|DFHOB]] molecules in its cytoplasm after induction. But theory tell us that all produced molecules may not go out of tje cell hence the membranous export system of E. coli is not adapted to the [[Team:Aix-Marseille/Integrated_Practices/Process#Glossary|DFHOB]]. To resolve this we decided to realize the lyse of bacteria in order to release the totality of siderophore molecules in the media. | ||
| + | A wide range of industrial lysis technique are available to perform this step. ( MENTON GAULIN ??) | ||
| + | '''This step consist in lyse the bacterial cells.''' | ||
<references/> | <references/> | ||
==Glossary== | ==Glossary== | ||
| + | |||
| + | '''Bioleaching''' : in simple words, leaching is metal extraction technique which rely on solubilization of metals ores (ore must be soluble and impurities must be insoluble) in a aqueous solution, by using strong acid solutions. Bioleaching in the same process but involves uses of living organism. | ||
'''DFHOB''': Desferioxamine B, a molecule able to catch metals with a very high affinity, as platinum. | '''DFHOB''': Desferioxamine B, a molecule able to catch metals with a very high affinity, as platinum. | ||
