Biomass gasification is a green and effective process to generate synthesis gas (syngas, CO + H2) with high heating value provided that inert species (e.g. N2) are removed from the products or inherently avoided in the feedstock. In this respect, the combination of oxygen gasification and pre-pyrolyzed biomass is extremely favourable for issuing a gas stream with high CO and H2 content that can be further converted to valuable chemicals. The application of chemical looping schemes permits O2 transfer from air to the reaction chamber via oxygen carriers, namely metal oxides having multiple oxidation states, without contemporary transfer of N2. In this manuscript the results of preliminary tests of chemical looping gasification are reported and discussed. The experiments were made at 900 °C with a synthetic oxygen carrier based on copper oxide. The conversion of biomass char to CO was investigated in batch-type tests providing insights into optimization of gasification atmosphere and oxygen carrier regeneration.