Research
| Title： | Yeast extract as a double-edged sword in microbial induced carbonate precipitation for copper remediation: Unraveling the nutrient-ligand dilemma |
|---|---|
| First author： | Zhang, Zijia; Zhou, Keqiang; Lu, Zijing; Garcia-Meza, J. Viridiana; Wu, Zhenbin; Xia, Ling; Hu, Xiheng |
| Journal： | PROCESS SAFETY AND ENVIRONMENTAL PROTECTION |
| Years： | 2025 |
| DOI： | 10.1016/j.psep.2025.108028 |
| Abstract： | Microbial-induced carbonate precipitation (MICP) is a promising strategy for heavy metal remediation, yet the role of organic nutrients in modulating metal sequestration remains underexplored. This study systematically investigates the dual functionality of yeast extract (YE) in MICP for copper (Cu2+) removal, focusing on its interplay as a nutrient source and a competing ligand. A highly ureolytic and Cu2+-tolerant strain, Lysinibacillus xylanilyticus SX1, isolated from copper tailings, was employed to evaluate YE's concentration-dependent effects. Results revealed that YE (0-2.0 g/L) enhanced SX1 growth and Cu2+ tolerance, while 3.0 g/L inhibited growth due to nutrient imbalance. Paradoxically, Cu2+ removal efficiency inversely correlated with YE concentration, declining from 62.8 % (1.0 g/L YE) to 6.8 % (3.0 g/L YE). Mineralogical analyses (XRD, FT-IR, XPS) identified Cu2(OH)2CO3 precipitation as the dominant mechanism at 1.0-2.0 g/L YE, whereas adsorption prevailed at 3.0 g/ L YE. Competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV) and UV-vis spectroscopy confirmed strong Cu2+-YE coordination (K ' CuYE = 1.2651 x 10 10-1.78238 x 10 10), which hindered carbonate mineralization. These findings highlight a critical trade-off between microbial viability and Cu2+ immobilization efficacy, emphasizing the necessity to optimize organic nutrient levels in MICP systems. |
