Effect and mechanism of mixed fungi synergistically enhancing the leaching of elements from wollastonite

The tight encapsulation of Ca 2+ in wollastonite by silicon-oxygen tetrahedra makes it difficult to leach, restricting the carbonation reaction rate. Microbial leaching technology offers distinct advantages for enhancing the release of carbon-fixing elements due to its mild operating conditions and low cost. While single-strain weathering of wollastonite has been thoroughly investigated, the effectiveness and mechanisms of mixed strains remain unclear. This study systematically investigated their dissolution patterns on wollastonite using a mixed culture of Ramichloridium apiculatum CMS-1 and Talaromyces pseudofuniculosus hzt-3′ in different ratios. The synergistic leaching mechanism of the mixed consortium was revealed through a comprehensive analysis of fermentation broth dynamics, residue transformation, and the expression of key metabolites, including organic and amino acids. The results demonstrated significantly superior Ca 2+ and Si 4+ leaching by mixed strains compared to pure cultures. The 20% CMS-1 + 80% hzt-3′ ratio achieved leaching efficiency of 79.95% ± 6.37% for Ca 2+ and 18.59% ± 0.11% for Si 4+ , representing an approximately 30.17-fold increase over CMS-1 pure culture (2.65% Ca 2+ leaching efficiency). Metabolic analysis showed accelerated polysaccharide consumption, increased extracellular proteins, and significantly elevated organic acid and amino acid production in mixed culture. The strain CMS-1 primarily produced oxalic acid (0.66 ± 0.033 mg/mL), while strain hzt-3′ mainly generated gluconic acid (1.60 ± 0.0798 mg/mL). In mixed culture, CMS-1 synthesized extracellular polysaccharides and proteins that were utilized by hzt-3′, which upregulated the production of gluconic acid, isocitric acid, L-glutamine, and L-tyrosine, collectively enhancing acidity and chemical dissolution. Additionally, surface cracks and grooves on leaching residues indicated additional biophysical disruption. IMPORTANCE This study elucidates the synergistic mechanism of a mixed microbial consortium for silicate weathering, a key process for enhanced mineral carbonation. It reveals how cross-feeding interactions between fungi upregulate organic acid production, dramatically accelerating wollastonite dissolution compared to single strains. The findings provide a novel and efficient biological strategy to overcome the intrinsic recalcitrance of silicate minerals, advancing the development of low-cost, environmentally friendly technologies for carbon dioxide sequestration through enhanced mineral carbonation.