The cumulative methane profile data was fitted to the
modified Gompertz equation (R2 > 0.99). The methane evolution had the S-shape trend and the kinetics data from
the equation was statistically significant. Methane production rate and yield were increased as the increased F/M
ratios and maximized at F/M of 5.0 (Fig. 3). The kinetics parameters were decreased when the F/M ratio above 5.0
(Table 2). Methane yield obtained from the present study was comparable to those in the previous studies (Table 3).
Little amount of VFA (< 5 mM) accumulated in the reactor content suggested that no inhibitory effect of VFA on
the microorganisms.