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 i 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 K2CO3, so that conversion proportional to total K2CO3 to solid carbon ratio is achieved with as high K2CO3 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.