High Efficiency Rare Earth Element Biomining with Systems Biology Guided Engineering of Gluconobacter oxydans

Abstract

The global demand for critical rare earth elements (REE) is rising1 with the increase in demand for sustainable energy technologies like wind turbines2,3, electric vehicles2,3, and high efficiency lighting4. Current processes for producing REE require high energy inputs and can produce disproportionate amounts of hazardous waste. Biological methods for REE production are a promising solution to this problem. In earlier work we identified the most important genetic mechanisms contributing to the REE-bioleaching capability of Gluconobacter oxydans B585. Here we have targeted two of these mechanisms to generate a high-efficiency bio-mining strain of G. oxydans. Disruption of the phosphate-specific transport system through a clean deletion of pstS constitutively turns on the phosphate starvation response, yielding a much more acidic biolixiviant, and increasing bioleaching by up to 30%. Coupling knockout of pstS with the over-expression of the mgdh membrane-bound glucose dehydrogenase gene, results in up to 73% improvement of REE-bioleaching.