Hydrogen-Producing Alga

[missybitsy]

Hi there,
Recently, there was an ISEF project regarding inducing anaerobic condition for Hydrogen-Producing Alga. This ISEF alumni tested his/her hypothesis by using different concentrations of sulfur. Why did this person use sulfur ? The web page below has a related research that explains the use of sulfur. Unfortunately, I couldn't understand!
http://aem.asm.org/cgi/content/full/71/10/6199

Can you please explain to me the purpose of using sulfur for this experiment ?

[deleted-71447]

Hi missybitsy,
Do you have a link or any other information about the ISEF experiment? It's hard to comment about the purpose of experiment without being able to see the materials and methods, etc.

If the ISEF project was related to this abstract, the student might have been testing for a threshold concentration of sulfur below which Chlamydomonas reinhardtii would start to produce H2, or some relationship between the sulfur concentration and the rate of H2 production. But that is really just a guess.

Chris

[MelissaB]

How much do you know about photosynthesis? Sulfur is a compound that plants need in order for certain parts of photosynthesis--namely, the part that produces oxygen--to occur. By taking away the alga's sulfur, it prevents the organism from producing any oxygen. The alga still uses energy, however, so it produces carbon dioxide and uses oxygen, just like we animals do. If you put it in an enclosed space, the alga will eventually replace all the oxygen with carbon dioxide and the conditions will be anoxic--without oxygen. Then the alga will switch to a different type of energy production and will make H2.

Does that make a bit more sense? I suggest you do some research on photosynthesis and also plant/algae respiration. If you still have questions, let us know.

[missybitsy]

I found this quick description of this person's project : http://www.usc.edu/CSSF/Current/Projects/S1713.pdf
Thank you so much for the information regarding photosynthesis. I came across this project yesterday and thought it's so interesting. I sure have a lot of background researches to do. I will start with photosynthesis and alga respiration first and will keep posting when I have more questions. In the mean time, do you have any other idea about the use of different concentrations of sulfur in the above project ?
Thanks for helping me!

[MelissaB]

It looks as if they were trying to find the best concentration of sulfur to produce hydrogen with. Keep in mind that cells need sulfur for other things, so if you restrict sulfur too much, you may also restrict cell growth and get reduced hydrogen production--though that doesn't seem to be what the other student found.

Photosynthesis and respiration are extremely fascinating, though somewhat complicated--so let us know if you have any other questions!

[missybitsy]

Hi, I've been trying to find a professor whose expertise is related to my project topic. So far, I haven't had any luck. I have also gathered some useful information about algae. If the algae was initially cultivated with an abundant amount of water and sunlight, they will be able to absorb carbohydrate which in turns provide them more energy to produce a significant amount of hydrogen. Another study mentioned that acetate could have an effect on the hydrogen absorption rate. Typically, if algae is grown in a sulfur-deprived condition, it'll stop producing hydrogen after a couple of days due to exhaustion. Then, if the sulfur is provided, the algae will continue the cycle again. Those are some of the information I gathered. I'm currently trying to find an idea topic to test the amount of hydrogen produces. The goal is to obtain as much as possible.
I'm also looking at how to simulate a "sulfur-deprived algae under anaerobic condition" experiment in a school laboratory environment. If you have any idea, please share it with me! Thank you so much!

[missybitsy]

Also, please reread the methods/material section of the ISEF alumni's paper. I would like to know what is TAP media , what does it consist of ? What could possibly be a way to measure cell density ? How does fuel cell work at obtaining and measuring hydrogen ?
Thanks for helping me!

[MelissaB]

Hi,

Unfortunately, this is a project that will definitely need to be done in a lab with proper safety equipment--hydrogen can be explosive (not surprisingly, since we can use it as a fuel)! Perhaps you can talk to your school teacher about this? They may have some ideas of how to create a proper environment.

Here's a website that seems to have a recipe for TAP media:
http://marine.rutgers.edu/ebme/html_docs/TAPMedia.htm

I'm not very familiar with algae, but I think you can measure cell density with a serial dilution and a spectrophotometer.

I'm not quite sure what you mean with your last question--can you try putting it into different words?

[missybitsy]

Hi, recent researches such as the one above used a fuel cell to measure the amount of hydrogen released from the algae. I would like to know how the fuel cell work. If fuel cell is hard to obtain, is there any other instrument you might think of that can measure hydrogen ?
Thanks !

[MelissaB]

Ah-ha. Here's some information on fuel cells, then: http://en.wikipedia.org/wiki/Fuel_cell . I suggest checking out the references listed in that article.