Effect of pH and sulfate concentration on hydrogen production using anaerobic mixed microflora

Anaerobic digestion of skim latex serum (SLS) for hydrogen and methane production using a two-stage process in a series of up-flow anaerobic sludge blanket (UASB) reactor

“…The possibly cause for having low hydrogen production could be due to the competition between hydrogen producing bacteria and sulfate reducing bacteria for using the same organic matters as electron donors to reducing either hydrogen or hydrogen sulfide. Both sulfate reducing bacteria and hydrogenogenic bacteria are able to be active at a pH range of 5.0e6.7 [6,15,17], which is similar to an operating pH range in this present work. Furthermore, activity of sulfate reducing bacteria is more favourable at neutral pH range, whilst hydrogenogenic activity is more favourable at an acidic pH range [15,17].…”

Deciphering acidogenic process towards biohydrogen, biohythane, and short chain fatty acids production: multi-output optimization strategy

“…However, high sulphate concentration diverts the bacterial pathway towards sulfate reducing bacteria (SRB) where initially sulfate is reduced to sulfite and then to sulfide. In fact, SRBs compete with H2-producing bacteria for the same electron donors resulting in lower hydrogen production (Chen et al, 2008;Hwang et al, 2009). Despite the application of untreated biocatalyst, experiment No.…”

Bio-hydrogen and bio-methane potentials of skim latex serum in batch thermophilic two-stage anaerobic digestion

“…The pH range 5-6 is suitable in the first reactor for both acidogenic (hydrogen producing) bacteria and sulfate reducing bacteria. In this step, SRB reduce sulfate to sulfide, meanwhile acidogens convert carbohydrates to hydrogen via the acetate and butyrate pathways, while other volatile fatty acids and solvents are simultaneous produced (Han and Shin, 2004;Hwang et al, 2009). However, this hydrogen producing stage removes only 10-20% of the organic matter in volatile solids (VS).…”