CO2 scrubber or algae bioreactors

[kgaur]

Hello,
I am doing a project this year on testing how nutrient type/concentration impacts CO2 filtration and biofuel production of Botryococcus braunii --the trouble is, I don't know whether to use a CO2 scrubber or an algae bioreactor. I know how to build both of them, but which one would be more beneficial to the success of my project, depending on what independent and dependent variables I am testing?

IV- nutrient concentration (10%, 15%, 20%, 25%)
nutrient types (nitrogen, phosphorous, potassium, sulfur)
DV- carbon dioxide concentration (kH/ppm), algal growth, biofuel production, pH, chlorophyll, % of lipid content, temperature

^Should I change or add anything? This isn't set in stone yet, just a general idea of what I'm planning to do...I probably going to take away some of the dependent variables and replace them with something else.

Which would be better for testing this project--a CO2 scrubber or an algae bioreactor? Also, I'm going into the 11th grade--is this an advanced topic for my level?

Thank you for your time.

Sincerely, Kriti

[SciB]

Hi Kriti,

You have a really great project and extremely timely too considering the interest in alternative oil sources. I'm a little confused as to your objective, however. Your mention of a CO2 scrubber sounds like you are thinking of using the alga to remove CO2, but you also talk about biofuel production. From what i know about B braunii, the main focus of research is on oil production, not carbon sequestration. There are other plants that are better carbon sinks.

My suggestion would be to build an algae bioreactor and concentrate on maximizing growth rate and oil production by testing the various nutrients and concentrations as you outlined in your post. Other potential IVs could be the intensity and duration of light, natural vs artificial light, the pH of the growth medium, presence of any micronutrients that the algae needs and temperature. You don't want to have too many test conditions, but some aspect like micronutrients may not have been tested by the big researchers and might yield some really interesting results.

I just did a search for 'botryococcus micronutrients' and found this paper from PLoS1 that might be interesting: http://www.ncbi.nlm.nih.gov/pubmed/22848502

Keep us posted here at Scibuddies as you progress in your study and we will continue to provide you with advice and suggestions.

Best wishes,

SciB

[kgaur]

Hi SciB,
Thanks for taking the time to reply back!

I actually did some research, and B. braunii has been used in some studies for CO2 sequestration and biofuel production. So I will most likely continue to use that, if not, Chlorella sp. might do nicely as an alternative. I will also most likely be using an algae bioreactor in my project. Thanks for the research paper, but I also had some other questions.

* How/where am I supposed to obtain the nutrients (nitrogen isn't easy to come by in liquid form), and is nutrient type/concentration even a significant variable with future application in today's world? If you really think about it...I don't know if it would have enough future applications, and I kind of want a lot of that in my project for this year.
*^ Would it be better to change it to something such as: enzyme type, nanoparticle type, or fertilizer type?
* Also, I might be testing biofuel efficiency as well...but I can't really find a way to do that. I don't think my parents would let me use their car for testing out algae biofuel...and I might make a battery to test the fuel, but I have no idea how to do that. Is there a way to even measure biofuel efficiency?

Please help me. Thanks for your time.

Sincerely, Kriti

[SciB]

Hi Kriti,

You had a question about the growth medium for B braunii, so i found a paper on optimizing culture conditions--see attached. The nitrogen requirement for the algae can be supplied by sodium nitrate. The other nutrients necessary for good growth are listed in the paper.

It sounds like you aren't sure which way to go with this project--optimizing growth or testing the biofuel potential. The two are connected. What you feed the algae is going to affect the lipid production, both type and amount. And, what you plan to use the lipids for--feedstock for chemical plant or fuel--also influences the growth conditions because changes in nutrients can produce more lipid of a type needed for a certain process.

There seems to be a lot of interest in poorer countries in using these algae as a fuel source and you might use that approach for your project--how can algae culture be best adapted for use under resource-limited conditions. Can B braunii be grown in water treatment plant ponds? Can it be grown in natural ponds where there is competition with other species? How can it be grown, harvested and processed most cheaply? This would be something the Gates Foundation would be interested in funding, i think.

How to reduce the level of carbon dioxide in the atmosphere is also a big topic now, so maybe you could tie B braunii fuel production with CO2 remediation and get two bangs for your buck. The algae takes CO2 from the air and makes hydrocarbons. The more hydrocarbons it makes, the more CO2 it uses--a win-win situation.

I hope i have given you some helpful suggestions in choosing a good direction for your project. Whatever you decide, i'm sure it will be interesting and challenging. That's the nature of research. If we always knew what the outcome was going to be then it would be boring--but we will often be surprised...and puzzled by the results.

Keep on posting,

SciB

[kgaur]

Hello SciB,

Thank you for the research paper! I found it quite useful.

I'm going to test both growth and biofuel production.

I'm probably going to change my focus to something else, but this has helped a lot. Thank you so much for everything.

Kriti

[kgaur]

Hello again,

I was wondering what would be an adequate algae sample size to use for a science project? Should I go with 30ml-50ml?

Thanks for your time.

Kriti

[SciB]

Hi Kriti,

The sample volume is probably something that you should establish empirically by trying your assays on a range of volumes. I can't tell you if 50 ml would work for your experiments. The greater the volume the more algae you will grow, so the volume really depends on how much algae you need to do an assay. I am speaking generally because i have no experience with growing algae for biofuel or any other use. I think your best plan would be to search the literature until you find a description of what volume of nutrient solution you would need to grow sufficient of your species of algae to measure the biofuel capacity accurately. Use that volume as your starting point and increase and decrease it and see how well your assays work. Then you will know the correct volume under your conditions.

If you have other specific questions, please repost as we may be able to help you avoid problems with your experimental setup.

Good luck,

SciB