An improved process for the catalytic gasification of a carbonaceous feedstock in a dual fluidized bed reactor for producing synthesis gas is disclosed. The disclosure uses γ-alumina as a catalyst support and heat carrier in the gasification zone (102). The gasification zone (102) is operated at 700 - 750 °C to prevent substantial conversion of γ-alumina to α-alumina, which would manifest in the enablement of high catalyst loading and high recyclability. The catalyst is an alkali metal, preferably K 2 CO 3 , so that conversion proportional to total K 2 CO 3 to solid carbon ratio is achieved with as high K 2 CO 3 loading as 50 wt% on the solid support. The combustion zone (140) is operated at 800° - 840° C, to prevent any conversion of the γ-alumina to α-alumina, so that catalyst recyclability of up to 98% is achieved between two successive cycles.