which is suitable for the
production of methane under mesophilic condition [10]. Alkalinity increased according to the amount of
banana peel (Fig. 3B). Alkalinity of TS 7.5% and 10% was in the range 1,000-5,000 mg CaCO3 L-1,
which is the optimum for the biogas production [11] and small amount of VFA and ethanol were
accumulated in the reactor content (Fig. 3C). VFA/alkalinity ratio during 156 hr fermentation was in the
range of 0-0.4 g CH3COOH g-1 CaCO3suggesting the optimum condition for the methane production (Fig.
3D). TVS removal decreased when %TS was increased. This trend was reversed compared with the
trends of methane potential and yield. The maximum removal of TVS was 28.4% obtained from TS 2.5%
and the minimum removal of TVS was 17.1% obtained from TS 10% (Fig. 4).