Due to the high organic load content, palm oil mill effluent (POME) has undergone various treatment systems. Most palm oil millers prefer to add a new approach to improve the existing treatment system but the investment and operation costs are too high to be incurred. Therefore, this study emphasizes the AB-101 microbial consortium performance in treating POME under the original operating parameters (0.2% AB-101 volume percentage, 7.5% molasses volume percentage and 100 ppm bio-activator dosage). The percentage reductions of POME characteristics under the original operating factor were 67.6% biochemical oxygen demand (BOD), 59.2% chemical oxygen demand (COD), 82.8% total suspended solids (TSS) and 66.7% oil and degrease (O&G). Meanwhile, POME treated with AB-101 under the optimal operating parameters (0.01% AB-101 volume percentage, 9.85% molasses volume percentage and 43.8 ppm bio-activator dosage) showed better characteristics of 92.9% BOD, 65.3% COD, 93.4% TSS and 95.5% O&G. Based on the proposed mechanism, lignocellulose degradation was greater when AB-101 was added into POME which improved the primary treatment of POME through enhanced anaerobic digestion.