Hydrogen production in batch culture of mixed bacteria with sucrose under different iron concentrations

Bio-Hydrogen Production from Pineapple Waste Extract by Anaerobic Mixed Cultures

“…SHPR increased when the substrate concentration increased from 20 to 25 g-total sugar/L and then SHPR slightly decreased with a further increase in substrate concentration (Figure 2a,b). The substrate limitation and substrate inhibition effects might be responsible for our findings [19,24,25]. Within the appropriate range, an increase in substrate concentration could improve the ability of hydrogen producing bacteria to produce hydrogen during the fermentation process [19,24,25].…”

“…The substrate limitation and substrate inhibition effects might be responsible for our findings [19,24,25]. Within the appropriate range, an increase in substrate concentration could improve the ability of hydrogen producing bacteria to produce hydrogen during the fermentation process [19,24,25]. However, a high substrate concentration could result in a high concentration of the short chain organic acid contained in pineapple waste extract and a low pH of the fermentation broth, which might be toxic to the growth of hydrogen producing bacteria.…”

“…The fermentation products were butyric acid, acetic acid, ethanol and propionic acid. The detection of butyric and acetic acids was a good indicator that efficient hydrogen production had been achieved [25] and that the fermentation type was butyrate-acetate type fermentation.…”

Succession of the Bacterial Community and Dynamics of Hydrogen Producers in a Hydrogen-Producing Bioreactor

“…A total of 25.6 liters of hydrogen was evolved in the batch fermentation, corresponding to a hydrogen yield of 3.11 mol H 2 mol sucrose Ϫ1 or 200 ml H 2 g sucrose Ϫ1 . The reported high hydrogen yields from sucrose in dark fermentation were 3.8 mol H 2 mol sucrose Ϫ1 by a Clostridium pasteurianum strain and 2.73 mol H 2 mol sucrose Ϫ1 by microflora (5,25). Over 72 h, the hydrogen-producing process was divided into five phases according to the hydrogen production rate: the lag phase (0 to 12 h after inoculation), exponential phase (12 to 16 h), stationary phase (16 to 24 h), early decline phase (24 to 36 h), and late decline phase (36 to 72 h) (Fig.…”

Enhancement of biohydrogen production from starch processing wastewater and further inside its ecosystem disclosed by 16S rDNA sequencing and FISH

“…Nevertheless, many publications informed different optimal initial iron concentration. Some works reported highest hydrogen production at initial iron concentration lower than 100 mg Fe/L [27] , while some studies obtained maximum yield at initial iron concentration higher than 300 mg/L [28] . Possible reasons may become from different substrate, source of microbes and/or dominant species, operated conditions.…”