This study demonstrates how genetic engineering can enhance bacteria's ability to extract rare earth elements (REEs), crucial for sustainable technologies, offering a greener alternative to traditional, environmentally damaging mining processes.
Researchers have successfully engineered Gluconobacter oxydans, a bacterium used in bioleaching, to more efficiently extract REEs. Bioleaching is a process where microorganisms dissolve metals from ore. The team focused on two key genetic mechanisms: phosphate transport and glucose oxidation.
By disrupting the phosphate-specific transport system (specifically deleting the pstS gene), the bacteria produced a more acidic solution, increasing bioleaching by up to 30%. They coupled this with over-expression of the mgdh gene, which is involved in glucose oxidation, further reducing the solution's pH and boosting REE extraction by as much as 73%.
These genetically modified bacteria offer a promising avenue for more sustainable REE extraction. Traditional methods often involve harsh chemicals and high temperatures, leading to significant environmental pollution. Bioleaching, especially with these enhanced bacteria, could significantly reduce the environmental footprint of REE production, making sustainable technologies more truly sustainable.
Gluconobacter oxydans is a heterotrophic microbe, meaning it consumes organic matter like sugars to produce energy. In this case, it converts glucose into a biolixiviant, a cocktail of organic acids that dissolve the solid matrix containing REEs. The pstS gene encodes a phosphate signaling protein, while mgdh codes for membrane-bound glucose dehydrogenase, an enzyme crucial for glucose oxidation.