The hydrothermal gasification of glucose with the addition of K2CO3 and two biomass feedstocks was performed in a continuous stirred tank reactor at 500 degrees C and 30 MPa. One biomass feedstock originated from plant material (phyto mass) and the other also contains meat (zoo mass). The amount of gases, the gas compositions, and the amount of intermediates formed during the hydrothermal treatment were determined. The most important difference is the unexpected low gas yield after conversion of the protein-containing biomass. Possible explanations are discussed. Severe corrosion has been observed in the experiments with zoo biomass.