Lignin-modifying enzymes have long been used in palm oil mill effluent (POME) treatment to remove the dark brown colour resulting from phenolic contamination. This study investigated a cost-effective industrial application method for optimizing phenol removal from POME using the termite-associated yeast Galactomyces reessii obtained from the subterranean termite under laboratory conditions. The yeast was cultured in POME, and the activity of the ligninolytic enzymes (laccase and manganese peroxidase) was monitored by spectrophotometry. Optimal conditions were achieved using a Box-Behnken experimental design. Results demonstrated that G. reessii reduced the phenolic compounds in POME by 88.69% with growth in 100% (v/v) POME using 30% (w/v) consortia and 5% (w/v) calcium carbonate (CaCO₃) at room temperature 30 ±1°C for seven days. G. reessii showed high performance for phenolic removal and decolourization of POME and other industrial wastewaters.