Effect of Substrate Concentration on Dark Fermentation Hydrogen Production Using an Anaerobic Fluidized Bed Reactor

Abstract

The effect of substrate (glucose) concentration on the stability and yield of a continuous fermentative process that produces hydrogen was studied. Four anaerobic fluidized bed reactors (AFBRs) were operated with a hydraulic retention time (HRT) from 1 to 8 h and an influent glucose concentration from 2 to 25 g L(-1). The reactors were inoculated with thermally pre-treated anaerobic sludge and operated at a temperature of 30 °C with an influent pH around 5.5 and an effluent pH of about 3.5. The AFBRs with a HRT of 2 h and a feed strength of 2, 4, and 10 g L(-1) showed satisfactory H(2) production performance, but the reactor fed with 25 g L(-1) of glucose did not. The highest hydrogen yield value was obtained in the reactor with a glucose concentration of 2 g L(-1) when it was operated at a HRT of 2 h. The maximum hydrogen production rate value was achieved in the reactor with a HRT of 1 h and a feed strength of 10 g L(-1). The AFBRs operated with glucose concentrations of 2 and 4 g L(-1) produced greater amounts of acetic and butyric acids, while AFBRs with higher glucose concentrations produced a greater amount of solvents.

Biohydrogen production from cassava wastewater in an anaerobic fluidized bed reactor

“…After it had been collected, the cassava wastewater was stored at 5 °C before usage. We chose to use the cassava wastewater with COD of 4 g COD/L, because, according to Amorim et al (2012), this concentration might favor the production of acetic acid and butyric acid (route that favors hydrogen production), whereas higher substrate concentrations would favor the production of solvents. Furthermore, Cappelletti et al (2011) concluded that a lower cassava wastewater COD produces a large amount of hydrogen.…”

Performance and composition of bacterial communities in anaerobic fluidized bed reactors for hydrogen production: Effects of organic loading rate and alkalinity

“…However, the abundance of EtOH production from the mixed culture used was most likely due to the dominance of Enterobacter and/or Klebsiella, as EtOH is one of the major products of these facultative anaerobes [13,30].…”

Fermentative biohydrogen production by anaerobic, Thermophilic bacterium thermoanaerobacterium aciditolerans Trau DAt isoalted from Vietnam

“…1). Hydrogen volume achievements in suitable condition were not as high as many earlier reports [2,3,13,14,16]. Since the hydrogen yield of strain Trau DAt in suitable condition was not high in comparison to some other thermophilic strains, the response surface methodology (RSM) with central composite design was applied for three important factors including glucose, yeast extract, iron concentration to enhance hydrogen production yield.…”

“…On the other hand, fermentative bacteria represent a promising means not only to reclaim energy from wastes in the form of hydrogen but also to utilize the wastes as sources. In addition, the dark fermentation using fermentative bacteria has many advantages: (1) It can produce H 2 all day long without light; (2) A variety of carbon sources can be used as substrates even biomass; (3) It produces valuable metabolites such as butyric, lactic and acetic acids as by products; (4) It is anaerobic process, so there is no O 2 . Thus, the dark fermentation for hydrogen production is the best choice for commercial biohydrogen production [1,4,5,9,12,14,20,23].…”

“…These advantages make the application of thermophiles for H2 production economical and technical feasible. By some above properties, hydrogen production of fermentative thermophilic bacteria has received more and more attention [2,8,15,16,17,19,24].…”