In this study, pretreatment of banana pulp using eggshells in both calcined and un-calcined forms to examine the extent of hydrolysis was conducted. Reactor CO containing banana pulp and inoculum but with no eggshells added was used as the control, while reactors C
1, C
2, C
3, C
4, and C
5 containing banana pulp and inoculum were spiked with 1, 3, 5, 7, and 9 g of un-calcined eggshells and calcined eggshells, for experiment 1 and 2, respectively. Anaerobic digestion was carried out at mesophilic temperature (35°C) for a period of 20 days. Digester C
3 with 5 g of calcined eggshells gave the largest cumulative biogas yield of 2343 mL with 62% CH
4, follow. The least biogas yield of 10 mL was obtained in digester C
5with 9 g of calcined eggshells additive.
Key words: Anaerobic digestion, banana pulp hydrolysis biogas, eggshells.