The present invention pertains to compositions and methods for more efficiently and effectively growing microalgae suitable for biofuel production. In one aspect, the invention pertains to a composition comprising microalgae and a suitable growth medium. The suitable growth medium comprises a nutritionally acceptable nitrate salt, and a carbonate salt. The concentration of nutritionally acceptable nitrate salt is from about 75 to about 200 μM while the concentration of carbonate salt is from about 1 to about 6 mM.
