Bio-based oxalic acid production in Issatchenkia orientalis enables sustainable rare earth recovery

Authors

• Jingxia Lu, University of Illinois Urbana-Champaign
• Wenjun Guo, University of Illinois Urbana-Champaign
• Ziye Dong, Lawrence Livermore National Laboratory
• Sarang S. Bhagwat, University of Illinois Urbana-Champaign
• Shih-I Tan, University of Illinois Urbana-Champaign
• Zhixin Zhu, University of Illinois Urbana-Champaign
• Andrew Johnson, University of Kentucky
• Jeremy S. Guest, University of Illinois Urbana-ChampaignFollow
• Rick Q. Honaker, University of KentuckyFollow
• Dan M. Park, Lawrence Livermore National Laboratory
• Yongqin Jiao, Lawrence Livermore National Laboratory
• Huimin Zhao, University of Illinois Urbana-ChampaignFollow

Abstract

The growing demand for rare earth elements (REEs) in clean energy and high-tech industries underscores the need for sustainable recovery methods and a reliable supply of processing chemicals. Here, we establish a microbial platform using the acid-tolerant yeast Issatchenkia orientalis SD108 to produce bio-oxalic acid for REE recovery. By introducing an oxaloacetate cleavage pathway and applying metabolic engineering, the engineered strain produces 39.53 g·L^-1 oxalic acid at pH 4.0 in fed-batch fermentation. The crude fermentation broth, used without purification, efficiently precipitates over 99% neodymium (Nd), 99% dysprosium (Dy), and 98% lanthanum (La) from individual REE chloride solutions. Recovery from a low-grade ore leachate achieves over 99% total recovery. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirm that REE oxalates precipitated with bio-oxalic acid closely resemble those obtained using commercial oxalic acid. Techno-economic analysis (TEA) and life cycle assessment (LCA) further demonstrate that bio-oxalic acid can be produced at a competitive price of $1.79·kg^-1 while reducing carbon intensity (CI) by 112% to 63.5% with and without electricity displacement, respectively, relative to the fossil-based benchmark. These results highlight bio-oxalic acid as a green, economically viable alternative to synthetic oxalate for sustainable REE recovery.

Document Type

Article

Publication Date

2026

Notes/Citation Information

© The Author(s) 2026

Digital Object Identifier (DOI)

https://doi.org/10.1038/s41467-026-68957-5

Funding Information

This work was funded by the DARPA Environmental Microbes as a Bioengineering Resource (EMBER) program (contract DE-AC52-07NA27344) (R.H., Y.J., and H.Z.). Distribution Statement A. Approved for public release: distribution is unlimited. The views, opinions, and/or findings expressed are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government. Work at LLNL was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DEAC52-07NA27344 (LLNL-JRNL-2014570). The online tool BioRender (biorender.com) was used to create Fig. 1 and Fig. 2a. We thank Vinh G. Tran from University of Illinois Urbana-Champaign for discussion about the metabolic engineering design, Keith D. Morrison from Lawrence Livermore National Laboratory for his assistance with X-ray diffraction data collection, and Forrest Dills form University of Kentucky for his assistance for precipitation test.

Repository Citation

Lu, Jingxia; Guo, Wenjun; Dong, Ziye; Bhagwat, Sarang S.; Tan, Shih-I; Zhu, Zhixin; Johnson, Andrew; Guest, Jeremy S.; Honaker, Rick Q.; Park, Dan M.; Jiao, Yongqin; and Zhao, Huimin, "Bio-based oxalic acid production in Issatchenkia orientalis enables sustainable rare earth recovery" (2026). Mining Engineering Faculty Publications. 21.
https://uknowledge.uky.edu/mng_facpub/21