The marine diatom Thalassiosira pseudonana grown under air (0.04% CO ) and 1 and 5% CO concentrations was evaluated to determine its potential for CO mitigation coupled with biodiesel production. Results indicated that the diatom cultures grown at 1 and 5% CO showed higher growth rates (1.14 and 1.29 div day , respectively) and biomass productivities (44 and 48 mg L  day ) than air grown cultures (with 1.13 div day and 26 mg L  day ). The increase of CO resulted in higher cell volume and pigment content per cell of T. pseudonana. Interestingly, lipid content doubled when air was enriched with 1-5% CO . Moreover, the analysis of the fatty acid composition of T. pseudonana revealed the predominance of monounsaturated acids (palmitoleic-16:1 and oleic-18:1) and a decrease of the saturated myristic acid-14:0 and polyunsaturated fatty acids under high CO levels. These results suggested that T. pseudonana seems to be an ideal candidate for biodiesel production using flue gases.