Biohydrogen production from apple pomace by anaerobic fermentation with river sludge

The biological hydrogen (bio-H2) production from apple pomace (AP) by fermentation using natural mixed microorganisms in batch process was studied under various experimental conditions. The river sludge was used as a seed after being boiled for 15 min. The results show that the optimal pretreatment for AP was to soak it in the ammonia liquor of 6% for 24 h at room temperature. An optimal fermentation condition for bio-H2 production was proposed that the pretreated AP at 37 °C, the initial pH of 7.0 and the fermentation concentration of 15 g/l could produce a maximum cumulative H2 yield (CHYm) of 101.08 ml/g total solid (TS) with an average H2 production rate (AHPR) of 8.08 ml/g TS/h. During the conversion of AP into H2, acetic acid, ethanol, propionic acid and butyric acid were main liquid end-products.