Optimization of the Symbiotic System Between Sulfate-Reducing Bacteria and Sulfide-Oxidizing Bacteria and Study on the Mechanism of Repairing Acidic Mine Drainage

Acidic mine drainage (AMD) rich in heavy metals and sulfates causes severe environmental hazards. SRB and SOB are ideal remediation strains, yet their microaerophilic symbiotic metabolism and metabolite characteristics remain ambiguous. This study explores their symbiotic metabolic mechanisms, optimizing culture parameters via response surface methodology and multi-objective genetic neural network algorithms. The optimal conditions are 32.60 °C, pH = 7.20, strain ratio at 1:1 and DO = 0.3–0.5 mg/L, achieving 80.27% sulfate removal and 60.60% elemental sulfur production. Under optimized microaerobic symbiosis, Cu2+, Zn2+ and sulfate removal rates reach 90.16%, 80.59% and 63.97%, with a S0 yield of 64.67%. SEM-EDS, XRD, XPS, and microbial diversity analysis verify that heavy metals are eliminated as metal sulfide precipitates, and most of the sulfate transforms into recyclable elemental sulfur.