Effects of SO₂ and NO on growth of Chlorella sp. KR-1

Effects of the toxic compounds in flue gas, SO_x and NO_x, on growth of Chlorella sp. KR-1 have been determined. Although growth of KR-1 was suppressed by the toxic compounds, KR-1 exhibited excellent tolerances to SO_x compared to other algal strains. When Chlorella KR-1 was cultured with the model gas containing 60 ppm SO₂, the linear growth rate was 1.24 g/l day which is about 25% lower than that of the control culture aerated with the gas mixture containing no toxic compounds, SO₂ and NO. KR-1 could grow even with the model gas containing 100 ppm SO₂ and the linear growth rate of KR-1 in the culture was 0.78 g/l day. The period for lag phase was increased with increasing of SO₂ concentration that also resulted in the decrease of the linear growth rate and the maximum cell concentration. Direct CO₂ fixation by Chlorella KR-1 has been successfully done using actual flue gases from a liquified natural gas (LNG)- or diesel-fueled boiler. These results indicated that Chlorella KR-1 may be applied for direct CO₂ fixation from actual flue gas.