The current study reports the evidence of enhancement in power generation from cellulosic biomass in microbial fuel cell (MFC) systems by supplementing dried Doraji (Platycodon grandiflorum) roots powder. Mediator-less two chamber H-type MFCs were prepared using rumen fluid as anode inocula to convert finely ground pine tree (Avicel) at 2% (w/v) to electricity. Dried Doraji roots were ground to pass 1 mm sieve and added to the anode of MFC at 0.1% w/v dosage for treatment. MFC power and current across an external resistor were measured daily for 10 d. At the end of incubation on d10, collected gases were measured for total gas volume and analyzed for gas composition on gas chromatography. Supplementation of Doraji roots powder to MFC anode chamber increased power generation and CO 2 production. Over the 10d experimental period, power density normalized to anode surface area were between 17.0 and 37.7 with average of 32.5 mW/m 2 in Doraji MFCs, and between 16.8 and 19.8 with average of 18.2 mW/m 2 in control group. CO 2 production increased and methane to CO 2 ratio decreased in Doraji root treatment comparing to control group. These observations imply that Doraji root components would inhibit methanogenesis and alter microbial fermentation of cellulose compounds favorable to produce bioenergy efficiently in MFC.