2. Materials and Methods
The experiments were performed in closed bioreactors of 6 liters. The biogas production was conducted under batch and fed batch process at ambient temperature.
2.1 Substrates and seed cultures
Pineapple peel solid waste was collected from a fruit canned processing plant in Karnchanaburi province, Thailand, and stored at 4o C before used. After that they were chopped into small pieces approximately 1 cm. in diameter before feeding into the reactor. The microorganisms used in this research were two kinds of mixed culture. One was collected from the same industrial sewage effluent and the other was the microorganism supported from one private company. Further, some chemical properties of pineapple peel were analyzed followed standard method [5].