This study evaluated the intermittent addition of coal flue gas wastes (CO2, SO2, NO and ash) into a Synechococcus nidulans LEB 115 cultivation in terms of growth parameters, CO2 biofixation and biomass characterization. The microalga from a coal thermoelectric plant showed tolerance up to 200 ppm SO2 and NO, with a maximum specific growth rate of 0.18 +/- 0.03 d(-1). The addition of thermal coal ash to the cultivation increased the Synechococcus nidulans LEB 115 maximum cell growth by approximately 1.3 times. The best CO2 biofixation efficiency was obtained with 10% CO2, 60 ppm SO2, 100 ppm NO and 40 ppm ash (55.0 +/- 3.1%). The biomass compositions in the assays were similar, with approximately 9.8% carbohydrates, 13.5% lipids and 62.7% proteins. (C) 2017 Elsevier Ltd. All rights reserved.