Evaluation of different pretreatment methods to prepare an inoculum for bio-hydrogen production from cassava starch wastewater

This research aimed to explore suitable pretreatments of anaerobic mixed cultures from the upflow anaerobic sludge blanket (UASB) granules and sediment before using them as inocula for biohydrogen fermentation. Four pretreatments were employed, i.e., dry heat, wet heat, acid, and base. Pre-treated anaerobic mixed cultures were used to produce hydrogen from cassava starch wastewater at an initial substrate concentration and pH of 25 g-COD/L and 5.5, respectively. UASB granule pre-treated at 105 °C for 2 h, gave a maximal hydrogen production and hydrogen production rate of 173.10 ml H2/L and 12.87 ml H 2/L h, respectively. Maximal hydrogen production (173.10 ml H2/L) was 17 times greater than that of the control (cassava starch wastewater only) (9.67 ml H2/L), indicating a significant enhancement in hydrogen production by use of pretreated seed inoculum. At maximal hydrogen production, a total energy production of 1.86 kJ/L was obtained.