Integration of lactic acid biorefinery with treatment of red mud from alumina refinery: win-win paradigm for waste valorization

Binyuan Gao; Xi Liu; Yudie Wu; Haina Cheng; Hongbo Zhou; Yuguang Wang; Zhu Chen

doi:10.1016/j.biortech.2024.130743

Integration of lactic acid biorefinery with treatment of red mud from alumina refinery: win-win paradigm for waste valorization

Bioresour Technol. 2024 Apr 25:401:130743. doi: 10.1016/j.biortech.2024.130743. Online ahead of print.

Authors

Binyuan Gao¹, Xi Liu¹, Yudie Wu¹, Haina Cheng², Hongbo Zhou², Yuguang Wang², Zhu Chen³

Affiliations

¹ School of Minerals Processing and Bioengineering, Central South University, Changsha Hunan, PR China.
² School of Minerals Processing and Bioengineering, Central South University, Changsha Hunan, PR China; Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha Hunan, PR China.
³ School of Minerals Processing and Bioengineering, Central South University, Changsha Hunan, PR China; Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha Hunan, PR China. Electronic address: zhuchen@csu.edu.cn.

PMID: 38677388
DOI: 10.1016/j.biortech.2024.130743

Abstract

The cost of detoxification and neutralization poses certain challenges to the development of an economically viable lactic acid biorefinery with lignocellulosic biomass as feedstock. Herein, red mud, an alkaline waste, was explored as both a detoxifying agent and a neutralizer. Red mud treatment of lignocellulosic hydrolysate effectively removed the inhibitors generated in dilute acid pretreatment, improving the lactic acid productivity from 1.0 g/L·h^-1 to 1.9 g/L·h^-1 in later fermentation. In addition, red mud could replace CaCO₃ as a neutralizer in lactic acid fermentation, which in turn enabled simultaneous bioleaching of valuable metals (Sc, Y, Nd, and Al) from red mud. The neutralization of alkali in red mud by acids retained in lignocellulosic hydrolysate and lactic acid produced from fermentation led to effective dealkalization, rendering a maximum alkali removal efficiency of 92.2 %. Overall, this study offered a win-win strategy for the valorization of both lignocellulosic biomass and red mud.

Keywords: Bioleaching; Detoxification; Lignocellulosic biomass; Rare earth elements.