Bioenergy Production from Sorghum Distillers Grains via Dark Fermentation

Sorghum distillers grains (SDGs) produced from a sorghum liquor company were used for generating biohydrogen via dark fermentation at pH 4.5-6.5 and 55 °C with a batch test, and the biohydrogen electricity generation potential was evaluated. The experimental results show that pH markedly affects hydrogen concentration, hydrogen production rate (HPR) and hydrogen yield (HY), in that high acidic pH values result in high values. The HPR and HY ranged from 0.76 to 3.2 L/L-d and 21.4 to 62.3 mL/g chemical oxygen demand, respectively. These hydrogen production values were used to evaluate bioelectricity generation using a newly developed gas/liquid-fuel engine. The results show a new and prospective biomass source for biohydrogen production, bioelectricity generation and simultaneously solving the problem of treating SDGs when producing kaoliang liquor. Applications of the experimental results are also discussed.