Showing posts with label nitrogen-fixing algae. Show all posts
Showing posts with label nitrogen-fixing algae. Show all posts

Thursday, October 14, 2010

CSB #2: Algae Power!

Right: Chisti with a photobioreactor
Definitions:
Photobioreactor: A production system in which all elements are controlled. In effect, there is no influence from the external environment other than light.
Nitrogen-fixing Algae: Algae which performs nitrogen fixation, a process which causes free nitrogen in the air to react with other elements to create more reactive substances, such as ammonia.

Summary:
Yusif Chisti of Massey University, New Zealand, believes that algae is the way to go in our world, where a new, clean, renewable energy source is desperately needed. However, contrary to many of today's experiments, which use freshwater algae, Chisti supports the use of marine algae for two reasons: first, it uses less freshwater, of which we have precious little, and second, it is easier to cultivate marine algae strains. Also, the marine strains can use waste carbon dioxide in its growing process and overall need a less complex habitat. One major problem is cultivating enough algae without using an equal amount of fossil fuels and an overlarge amount of fertilizer. As Chisti says, the way in which the algae is grown significantly affects its oil content. However, at this point, it needs too much energy to be a practical solution. Scientists are exploring nitrogen-fixing algae, and a possible solution for the energy requirement is a photobioreactor, which is more efficient than the current "grow it in a pond" method. Before algae can become a reliable energy source, though, much work is needed.

Discussion:
I agree with Professor Chisti that the way in which algae is grown can greatly affect its lipid content. I have done a lot of research on algae because it was part of my science project last year, and I was interested in this article because of that. Although energy efficiency is still a problem, it is true that algae would be a relatively simple change from fossil fuels, but it burns cleanly and is renewable. It is interesting that freshwater algae require more care as compared to marine strains, although this may be because marine algae is more used to changes in temperature and pH. This is because freshwater algae grows in sheltered ponds, into which there is no flow of water. I was not aware before that fertilizer usage as well as energy usage is a problem, but it is true that fertilizer is a somewhat exhaustible resource, so it would be good to reduce dependency on and usage of it.

Questions:
1) Why would nitrogen-fixing algae be more energy efficient than the average marine strain?
2) What methods of cultivation maximize lipid production?

Sources:
Nitrogen fixation:
"Nitrogen Fixation." Encyclopædia Britannica Online. Encyclopædia Britannica,
n.d. Web. 14 Oct. 2010. .
Article citation:
Extance, Andy. "Marine Algae Offer Sustainable Fuel Hope." environmental
research web. IOP, 13 Oct. 2010. Web. 14 Oct. 2010.
Article URL:
http://environmentalresearchweb.org/cws/article/news/44012