Developing a Scalable System for Biorecovery of Critical Materials from Industrial Waste with Gluconobacter Oxydans
Organic acid production by Gluconobacter oxydans has been proposed as part of a potential economical and environmentally friendly heterotrophic bioleaching process for recovery of rare earth elements from industrial waste. To provide organic acids in a quantity and at a rate useful for commercial bioleaching, continuous culture of the acid-producing organism will be necessary. The objective of this research project was to determine optimal conditions for continuous cultivation of G. oxydans for production of organic acids. Cultures were subjected to dilution rates ranging from .05 hr-1 to .38 hr-1 to determine the optimum conditions for production of lixiviant agents. Previous studies have identified methods for maximizing production of gluconic acid and 2,5-diketogluconic acid from G. oxydans, yet the utilization of these and other unidentified G. oxydans metabolites for leaching of rare earth metals is largely unexplored. Continuous cultures exhibited sustained organic acid production for at least 110 hours, while batch fermentations showed slowed growth rates after 16 hours. Several parameters, namely optical density, dissolved oxygen, organic acid concentration and pH, were monitored to characterize the steady state conditions of the fermentation process. The observed trend was increasing acidity with decreasing dilution rates, as the lowest dilution rate of 0.05 hr-1 yielded the highest gluconic acid concentration of 176 mM and lowest pH of 2.20. Trace amounts of 2,5-diketogluconic acid were detected only at the 0.05 hr-1 dilution rate, likely because the pH of the bioreactors was not maintained within the window for gluconate dehydrogenase activity [Silberbach, M., et al., Appl Microbiol Biotechnol, 2003. 62(1): p. 92-8].
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- DOE Contract Number:
- AC07-05ID14517
- OSTI ID:
- 1504923
- Report Number(s):
- INL/EXT-16-39515-Rev000
- Country of Publication:
- United States
- Language:
- English
Similar Records
Organic acid production from food wastes using Gluconobacter oxydans: A possible source of cheaper lixiviants for leaching REE from end-of-life products
Gene editing of Gluconobacter oxydans for improved xylose metabolism and bioleaching