This study undertook gasification reactivity measurement of an algal biomass (Chlorella sp.) char prepared in two different reactors with two gasifying agents (CO2 and steam) and compared that with similar measurements on woody biomass (commercial wood mix) char in a thermo-gravimetric analyser at three different temperatures. In general, the woody char from entrained flow reactor showed higher reactivity during gasification. At 800 degrees C and 950 degrees C, similar reactivity was exhibited by algal char from thermo-gravimetric analyser whereas at 1100 degrees C, the woody char became more reactive than the algal char. For algae, the char prepared in entrained flow reactor showed lower reactivity than the char from thermo-gravimetric analyser. The scanning electron microscope images of the char samples showed significant difference in morphology with respect to the char preparation condition and species. For chars of both the species, a temperature of 800 degrees C and time of around 20 min are found to be sufficient to accomplish most conversion; this information is of practical relevance. (C) 2013 Elsevier B.V. All rights reserved.