Student Experiment: P-Limitation for lipid accumulation (Is this a good experiment to perform?)
November 27, 2017
I recently had a student write to ask about phosphorus limitation for nutrient limitation.
The questions were:
Which strains to use?
Which media to use?
How do I do it?
I'm going to be a giant bucket of cold water on you, in multiple ways.
First, P-limitation does not really have a large effect on lipid accumulation. The last time I did these tests with a former client with 20 or so strains the N-limitation effect was 10-20x more potent than the P-limitation. Keep in mind, you are considering limiting a phosphate a key element in phospholipids
Second, they are incredibly difficult experiments to pull off (measuring lipids is technically challenging- need a mass spectrometer) and isolating p-limitation in a algae culture is difficult as bacteria (ubiquitous) will recycle P from the water. And one more bucket, just do it with ONE algae strain with a larger number of replicates (n).
But I have to choose;ChlorellaorNannochloropsis.
Media: You may want to make your own. Check out our media recipes. You are are looking at REPLETE and DEPLETE conditions. Watch your P-ions from other salts being added. All medias used with the weed algae strains can tolerate >10x normal nutrients. Use this to your advantage when you limit P.
To limit, give them a fraction of the P as they would normally need to grow the culture. They will still require some.
Probability of success: If I were to do this myself, in my lab, with a 20-hour per week technician, I would give myself 10 weeks and a 80% chance of failure.
A good project: As a former resident of HB. I suggest going around to the little bits of waterway and seeing if they are ripe for algae blooms. Try thiskit.