Transcript 09-31705357 Biohydrogen as Future Energy Source

Biohydrogen as Future Energy Source
About Me
Background
Summary of Paper 1
Hi, my name is Shin and I am currently studying Biotechnology in Murdoch University,
Western Australia.
For one of my assessments, I am required to create a website with information related to
microbes processes in relation to real world applications. I have chosen to base my topic on
using biohydrogen as future energy source because I think it is interesting and meaningful
because there are many people who still don’t know about such information.
Summary of Paper 2 This webpage will compare two articles regarding production of biohydrogen by two
Comparison
Discussion
References
different methods. One utilizes the use of a hyperthermophilic bacterium, Thermotoga
Neapolitana while the other focuses on biohydrogen production from food waste.
Background
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About Me
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Background
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Summary of Paper 1
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Summary of Paper 2
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Comparison
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Discussion
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References
The need for energy has been growing exponentially for the last century. While fossil fuels are
depleting in a rapid rate, scientists have suggested the use of hydrogen as the fuel of the future.
The field of biohydrogen had become a promising area of research.
What is biohydrogen?
Biohydrogen refers to hydrogen produced biologically, typically by algae, bacteria and archae.
For more information, check out Biohydrogen (wikipedia).
Why Hydrogen?
Hydrogen is widely abundant, it has high energy content and can be produced from renewable
feedstocks. (Nguyen, 2008) Unlike burning fossil fuels, in its purest form, hydrogen produces
water instead of greenhouse gas when combusted and releases no greenhouse gas and
produces no pollution. (Johnston, 2005)
Ways to generate biohydrogen
Hydrogen is not a primary source of energy, thus must be manufactured. Several ways to
generate hydrogen include:
1) Photosynthetic unicellular organisms that utilize either nitrogenase or dehydorogenase
reactions to produce hydrogen
2) Fermentative bacteria that produce hydrogen anaerobically
3) Various stepwise processes in which a combination of bacteria of one population
predigests more complex organic molecules to make less complex feedstock of simple
organic molecules that can be subsequently used by hydrogen-producing organisms.
Summary of Paper 1
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About Me
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Background
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Summary of Paper 1
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Summary of Paper 2
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Comparison
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Discussion
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References
Van Ooteghem, S. A., Beer, S. K., & Yue, P. C. (2002). Hydrogen production by the thermophilic
bacterium Thermotoga neapolitana. In Biotechnology for Fuels and Chemicals (pp. 177-189).
Humana Press.
“Thermotogales is an order composed of rod-shaped, gram-negative, non-sporulating
bacteria that have a loose surrounding membrane or “toga”.” (Van Ootenghem et al,
2002)
Van Ooteghem et al. explored the potential of Thermotogales order, particularly
focusing on optimizing thermotoga neapolitana due to its robust and adaptive nature in
varying environment.
Unlike earlier experiments which dealt with Thermotoga neapolitana strictly In
anaerobic environment, Van Ootenghem et al. found that the species was able to utilize
reduced levels of oxygen and generating hydrogen as endproduct, thus a
“microaerophile”. Van Ootegham et al. also suggested that by providing low levels of
oxygen, Thermotoga neapolitana are able to shift its metabolic behaviour to a more
energy efficient catabolic pattern which in turn produces greater hydrogen and
generates greater metabolic efficiency compared to those grown under anaerobic
condition.
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Summary of Paper 1 (Part 2)
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About Me
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Background
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Summary of Paper 1
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Summary of Paper 2
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Comparison
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Discussion
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References
Next
Summary of Paper 1 (Part 3)
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About Me
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Background
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Summary of Paper 1
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Summary of Paper 2
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Comparison
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Discussion
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References
Summary of Paper 2
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About Me
Han, S. K., & Shin, H. S. (2004). Biohydrogen production by anaerobic fermentation of
food waste. International Journal of Hydrogen Energy, 29(6), 569-577.
Fermentation of food waste occur at different rate because of the different
characteristics of different food components. Dilution Rate (D) is the tool that is
used to control the optimum condition of such process.
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Background
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Summary of Paper 1 Han and Shin attempted to optimize biohydrogen production by anaerobic
fermentation of food waste by altering different factors such as pH and D.
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Summary of Paper 2 At optimum D, the highest productivity achieved by Han and Shin was 70.8%, by
Comparison
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converting converts chemical oxygen demand (COD) to hydrogen (19.3%), volatile
fatty acid (36.5%) and ethanol (15%).
It was found that under the optimal D, it could lead the to favor microbial growth
(hydrogen production) and delay the shift of predominant metabolic flow from
hydrogen and acid-forming pathway to solvent-forming pathway.
Han and Shin concluded that a two-stage processes would provide the preferred
environments for acidogenic hydrogenesis and methanogenesis.
More studies are yet to be done to further improvise the process.
Summary of Paper 2 (Part 2)
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About Me
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Background
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Summary of Paper 1
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Summary of Paper 2
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Comparison
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Discussion
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References
Fig.2. The effect of initial D on VFA, pH and hydrogen production during
hydrogen fermentation of food waste.
Comparison between two articles
Two articles explored two different methods of biohydrogen production.
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About Me
Background
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Summary of Paper 1
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Summary of Paper 2
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Comparison
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Discussion
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References
Both methods are proven to be effective in producing hydrogen under the right
condition.
Paper 1 focused on production of biohydrogen through fermentation by
hyperthermophilic bacteria.
Paper 2 focused on production of biohydrogen through fermentation of food waste.
Highest productivity efficiency achieved using thermatogales is 71% while
fermentation of food waste achieved 70.8%.
Both methods have similar productivity efficiency when used under optimum
conditions.
Discussion & Comments
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About Me
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Background
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Summary of Paper 1
Although productivity efficiency are similar for both methods, I believe production of
biohydrogen by fermentation of food waste is more ecological as it not only generates
biohydrogen but also utilizes waste materials which had been increasing in the past 10
years. By devising a effective system, we could not only produce substantial amount of
biohydrogen but also tackle issues regarding waste materials.
It is also important to note that generation of biohydrogen through Thermotoga
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Summary of Paper 2
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Comparison
Both methods are inexpensive and effective in its productivity.
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Discussion
Many researches are now being done on improvising ways to generate biohydrogen.
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References
Neapolitana provide important advantages as it reduces chances of contamination and cost
for cooling.
References
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About Me
Han, S. K., & Shin, H. S. (2004). Biohydrogen production by anaerobic fermentation
of food waste. International Journal of Hydrogen Energy, 29(6), 569-577.
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Background
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Summary of Paper 1 21st century. Technovation, 25(6), 569-585.
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Summary of Paper 2 Nguyen, T. A. D., Pyo Kim, J., Sun Kim, M., Kwan Oh, Y., & Sim, S. J. (2008).
Johnston, B., Mayo, M. C., & Khare, A. (2005). Hydrogen: the energy source for the
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Comparison
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Discussion
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References
Optimization of hydrogen production by hyperthermophilic eubacteria,
Thermotoga maritima</i> and< i> Thermotoga neapolitana in batch fermentation.
International Journal of Hydrogen Energy, 33(5), 1483-1488.
Van Ooteghem, S. A., Beer, S. K., & Yue, P. C. (2002). Hydrogen production by the
thermophilic bacterium Thermotoga neapolitana. In Biotechnology for Fuels and
Chemicals (pp. 177-189). Humana Press.