Supercritical water gasification (SCWG) of bagasse was performed in the presence of unpromoted and zinc promoted Ru/gamma-Al2O3 nanocatalysts prepared with impregnation and microemulsion techniques. Nanocatalysts were characterized by ICP, BET, XRD, H-2 chemisorption, and TEM techniques. The microemulsion technique decreased the catalyst average particle size to 3.9 nm and increased the percentage dispersion and reduction to 89.6% and 90% respectively. Using the microemulsion technique for preparation of Ru/gamma-Al2O3 increased the hydrogen yield to 15.6 (mmol of H-2/g of bagasse) and CO yield to 7.5 (mmol of CO/g of bagasse). Promotion of Ru/gamma-Al2O3 with 1.5 wt.% zinc increased the total gas yield by 6.6%. The yields of hydrogen and carbon monoxide increased by 16.67% and 725%. The yield of methane decreased by 32.7%. (C) 2014 Elsevier B.V. All rights reserved.