Dark Fermentation of Sweet Sorghum Stalks, Cheese Whey and Cow Manure Mixture: Effect of pH, Pretreatment and Organic Load

The aim of this study was to determine the optimal conditions for dark fermentation using agro-industrial liquid wastewaters mixed with sweet sorghum stalks (i.e., 55% sorghum, 40% cheese whey, and 5% cow manure). Batch experiments were performed investigate effect controlled pH (5.0, 5.5, 6.0, 6.5) on production bio-hydrogen volatile fatty acids. According obtained results, maximum hydrogen yield 0.52 mol H2/mol eq. glucose measured at 5.5 accompanied by highest acids production, whereas similar productivity also observed 6.0 6.5. use heat-treated anaerobic sludge as inoculum had a positive impact exhibiting an increased 1.09 glucose. On other hand, pretreated (ensiled) instead fresh one, led lower while organic load decrease did not affect process performance. In all experiments, main end-products acetic, propionic, butyric), ethanol lactic acid.