Functional fungal pellets self-immobilized by mycelium fragments of Irpex lacteus WRF-IL for efficient degradation of sulfamethazine as the sole carbon source

In order to achieve an efficient microbial material with dual functions of self-immobilization and sulfamethazine (SMZ) degradation, this study explored the pelletization technique utilizing mycelium fragments of Irpex lacteus WRF-IL and systematically examined the pellets formation conditions and degradation capability. The Box-Behnken design results demonstrated that pure mycelium fragments, broken by frosted glass beads, could be rapidly self-immobilized to form white rot mycelial pellets (WRMPs) within 24 h, serving as the pelleting core. These WRMPs could completely remove SMZ as the sole carbon source within 20 h. The addition of sucrose expedited this process, achieving complete removal within only 14 h. Kinetic analysis showed that WRMPs could potentially remove SMZ at higher concentrations (>25 mg/L). Biodegradation was the primary pathway of SMZ removal. Seven intermediates were identified by QTOF LC/MS, and three transformation pathways initiated by SO₂ overflow, molecular rearrangement, and aniline moiety oxidation were deduced.