MadSci Network: Microbiology

Re: Using a spectophotometer to determine algae biomass

Date: Wed Nov 17 15:48:31 2010
Posted By: Jeff Buzby, Ph.D., CHOC Research Institute
Area of science: Microbiology
ID: 1289835817.Mi

Dear James:

It's not completely clear exactly how you're growing your algae nor what type(s) of algae you're using, but I'll make a few assumptions & tell you what I can.

Since you're using a spectrophotometer, I'll assume you're growing them under somewhat std. liquid culture conditions.  My only experience w/ algae was work w/ blue-green algae/cyanobacteria for my thesis/post-doctoral research many moons ago.  For our liquid cultures, we used turbidimetric light-scattering to measure their optical density in the same manner that bacterial culture optical densities are determined.  In this case, light absorbance by chlorophyll & other pigments is ignored.  However, the wavelength used for determining culture optical densities must be adjusted to avoid any pigment absorbance while remaining suitable for measuring light-scattering by the algae.  For the blue-greens, we used 550 nm, slightly shorter than the 650 nm typically used for non-absorbent bacterial cultures.

If you're studying eukaryotic algae, they'd be considerably larger than the blue-greens & their pigment absorbance spectrum may differ somewhat.  But I would think you could use the same principles that were applied to the blue-greens to find a suitable wavelength for determining their optical densities, as well.

In summary, I would recommend avoiding any method that depends on pigment analysis.  If spectrophotometry doesn't work out, you might even be able to plate the algae out on solid culture media & count colonies.  It would be much more laborious & may not even be feasible for some algae.  But it would be another approach for directly measuring cell numbers/biomass in the liquid cultures.


Best of luck w/ your studies & I hope this advice is helpful,


Jeff Buzby, Ph.D.
CHOC Research Institute

Current Queue | Current Queue for Microbiology | Microbiology archives

Try the links in the MadSci Library for more information on Microbiology.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-2006. All rights reserved.