The research study is based on alkaline hydrothermal liquefaction of rice straw using NiO nanoplates where temperature, reaction time and molar concentrations of alkali (NaOH) were varied to optimize lactic acid (LA) production. The highest yield of 58.81% for lactic acid was obtained at 260 degrees C for 2h with 1M NaOH and 0.052 g NiO nanoplates attributing to complete degradation of cellulosic rice straw. Influence of different morphological forms of NiO like nanoparticles, nanoplates and porous nanosheets were also investigated in this perspective where nanoplates had better catalytic activity. Lactic acid production was found to be highly dependent on and sensitive to slight changes in alkaline conditions in the existence of NiO nanoplates as catalyst. (C) 2016 Elsevier B.V. All rights reserved.