Abstract A green microalga, Acutodesmus sp., a close rela-
tive of Acutodesmus deserticola, was isolated from the waste-
water discharges of an oil refinery in India. This study exam-
ined the effects of light intensity, temperature, pH, and high-
CO2 treatments (up to 20 %) on the growth of the alga and
investigated the effects of different CO2 treatments on its mac-
romolecular composition (protein, carbohydrate, and lipids).
Under controlled laboratory conditions, the alga showed high
growth rates over a wide range of light (up to 700 μmol
photons m−2 s
−1
), temperature (up to 40 °C), and pH (5–10)
conditions. In the stationary phase, the highest protein and
carbohydrate content was found to be 71.52 and 40.72 % of
dry weight at 5 and 15 % CO2, respectively. After 5 days of
cultivation, the maximum dry weight biomass attained in
these cultures was 1.149, 1.99, 1.75, and 1.65 g L−1 at 5, 10,
15, and 20 % CO2, respectively, indicating that this strain has
significant tolerance to CO2. These results indicate that this
strain is a promising candidate for use in biofixation of CO2
from the flue gases emitted by industries, and it also has a
strong potential as a feedstock for value-added substances.