Batch experiments were carried out to investigate the degradation effect of Chlorella pyrenoidosa (KX686118) on the phenolic effluent of a coal gasification (CG) plant. The major pollutant present in the effluent is phenol (C6H5OH). The effect of C. pyrenoidosa on phenol degradation was analyzed by inoculating 1 g of wet biomass into four different phenolic effluent concentrations viz. 20, 40, 60 and 80% i.e. the total phenols concentration of 282 +/- 1, 564 +/- 1.5, 846 +/- 2.2 and 1128 +/- 2 mg L-1 respectively. The experiments were performed under ambient temperature of 30 +/- 5 degrees C at pH 8.0. The results indicated that 1g of wet biomass per Liter of effluent could degrade more than 90% of phenol and other contaminants, for effluent concentrations up to 60%. Bio kinetic coefficients viz., k-reaction rate constant and K-m-half saturation constant were determined using Michaelis-Menten rate expression and found as k=50 mg of phenol g(-1)(algae) day(-1), Km=347 mg L-1. The highest carbon fixation rate of 0.25 g L-1 day(-1) was obtained with a 60% effluent concentration. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.