scholarly journals Hydrogen Production from Synthesis Gas Using the Photosynthetic Bacterium Rhodospirillum rubrum

2005 ◽  
Vol 5 (1) ◽  
pp. 35
Author(s):  
Ghasem Najafpour ◽  
Habibollah Younesi
Keyword(s):  
Mass Transfer ◽  
Carbon Source ◽  
Hydrogen Production ◽  
Synthesis Gas ◽  
Rhodospirillum Rubrum ◽  
Anaerobic Bacteria ◽  
Photosynthetic Bacterium ◽  
Attractive Alternative ◽  
Agitation Rate ◽  
Acetate Concentration

Production of biological hydrogen by anaerobic photosynthetic bacteria, specifically Rhodospirillum rubrum, from synthesis gas was successfully conducted at ambient temperature and pressure. The influence of initial acetate concentration as the substrate for microbial growth was investigated in a batch system. Series of experiments were conducted using serum bottles as bioreactor. The agitation rate and light intensity were adjusted at 200 rpm and 1,000 lux, respectively. The concentration of acetate as carbon source was varied from 0.5 to 3.0 g/I. It was observed that the increase in concentration of the carbon source from 2.5 to 3 g/l resulted in the decrease both in the growth of the microorganism and in hydrogen production rate. Experimental results showed that the optimum acetate concentration would be from 1 to 2 g/I. The resulting data also showed that in 1-2 g/I acetate, highest hydrogen formation and cell concentration were obtained. Additional acetate in the initial culture medium inhibited the growth of R. rubrum. An inverse relationship between acetate concentration and initial cell growth was observed. This article presents a method to calculate the mass transfer coefficient for gaseous substrates and the process parameters involved in a gas and liquid fermentation system. The procedure had been defined by experimental data for the bioconversion of CO to C02' while H20 is converted into hydrogen. Hence, a biologically-based water-gas shift reaction provided an attractive alternative improvement for renewable resources to achieve higher hydrogen production. Keywords: Anaerobic bacteria, batch culture, coefficient, CO uptake rate, mass transfer, photobiological hydrogen, and Rhodospirillum rubrum.

ROLE OF FLOW AND MASS TRANSFER IN PHOTOBIOREACTOR: FROM BACTERIA LOCOMOTION TO HYDROGEN PRODUCTION

2018 ◽  
Author(s):  
Xun Zhu ◽  
Qiang Liao ◽  
Rong Chen ◽  
Ao Xia ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Hydrogen Production

scholarly journals Zeolite addition to improve biohydrogen production from dark fermentation of C5/C6-sugars and Sargassum sp. biomass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. M. Silva ◽  
A. A. Abreu ◽  
A. F. Salvador ◽  
M. M. Alves ◽  
I. C. Neves ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Anaerobic Bacteria ◽  
Dark Fermentation ◽  
Inorganic Materials ◽  
Biohydrogen Production ◽  
High Rate ◽  
Continuous Reactor ◽  
Organic Loading Rate ◽  
Fermentation Products ◽  
Zeolite Type

AbstractThermophilic biohydrogen production by dark fermentation from a mixture (1:1) of C5 (arabinose) and C6 (glucose) sugars, present in lignocellulosic hydrolysates, and from Sargassum sp. biomass, is studied in this work in batch assays and also in a continuous reactor experiment. Pursuing the interest of studying interactions between inorganic materials (adsorbents, conductive and others) and anaerobic bacteria, the biological processes were amended with variable amounts of a zeolite type-13X in the range of zeolite/inoculum (in VS) ratios (Z/I) of 0.065–0.26 g g−1. In the batch assays, the presence of the zeolite was beneficial to increase the hydrogen titer by 15–21% with C5 and C6-sugars as compared to the control, and an increase of 27% was observed in the batch fermentation of Sargassum sp. Hydrogen yields also increased by 10–26% with sugars in the presence of the zeolite. The rate of hydrogen production increased linearly with the Z/I ratios in the experiments with C5 and C6-sugars. In the batch assay with Sargassum sp., there was an optimum value of Z/I of 0.13 g g−1 where the H2 production rate observed was the highest, although all values were in a narrow range between 3.21 and 4.19 mmol L−1 day−1. The positive effect of the zeolite was also observed in a continuous high-rate reactor fed with C5 and C6-sugars. The increase of the organic loading rate (OLR) from 8.8 to 17.6 kg m−3 day−1 of COD led to lower hydrogen production rates but, upon zeolite addition (0.26 g g−1 VS inoculum), the hydrogen production increased significantly from 143 to 413 mL L−1 day−1. Interestingly, the presence of zeolite in the continuous operation had a remarkable impact in the microbial community and in the profile of fermentation products. The effect of zeolite could be related to several properties, including the porous structure and the associated surface area available for bacterial adhesion, potential release of trace elements, ion-exchanger capacity or ability to adsorb different compounds (i.e. protons). The observations opens novel perspectives and will stimulate further research not only in biohydrogen production, but broadly in the field of interactions between bacteria and inorganic materials.

Sign in / Sign up

Export Citation Format

Share Document