Disclosed herein are magnetotactic algae, such as algae cells that include magnetic nanoparticles. In some examples the magnetotactic algae express a nucleic acid molecule encoding a bacterial MagA ferrous transporter, a nucleic acid molecule encoding a bacterial Mms6 magnetite binding protein, or both. Also disclosed herein are methods for producing magnetotactic algae and methods of producing biofuel or magnetic nanoparticles utilizing magnetotactic algae. Further disclosed herein are methods of enriching a population of magnetotactic algae cells (for example, increasing the number of magnetotactic algae cells in a population of algae cells). In further embodiments, disclosed herein are methods of selecting a transformed algae cell.
ACKNOWLEDGMENT OF GOVERNMENT SUPPORT
 This invention was made with government support under Contract No. DE-AC52-06NA25396 awarded by the U.S. Department of Energy. The government has certain rights in the invention.