[Bioaugmentation of hydrogen producing bacteria on operation of bio-hydrogen producing reactor]

Hydrogen producing strain Ethanoligenens sp. B49 was inoculated into activated sludge of continuous stirred tank reactor (CSTR)to bioaugment hydrogen production. Hydrogen production capacities, compositions of fermentation products and pH value before and after bioaugmentation were investigated. When organic loading rate was 12 kg/(m3 x d), bioaugmentation of hydrogen producing strain enhanced hydrogen production rate and improved the composition of fermentation products significantly. After bioaugmentation, hydrogen production rate increased from 3.6 mmol/(kg x d) to 5.7 mmol/(kg x d), which was 1.5 times as that before bioaugmentation. Before bioaugmentation, average concentration of ethanol, acetic acid and propionic acid were 6.8 mmol/L, 5.3 mmol/L, 4.8 mmol/L respectively, while after bioaugmentation, those were 10.5 mmol/L, 7.5 mmol/L and 1.7 mmol/L respectively. Ethanol and acetic acid accounted for 86.8% in total fermentative products after bioaugmentation, while only 72% before bioaugmentation. pH value of effluent dropped from 4.5-4.7 to 4.3. Bioaugmentation of hydrogen producing strain is helpful to promote the formation of ethanol-type fermentation in low organic loading rate.