NOVELTY - Method (M1) of syngas treatment, comprises: (A1) providing raw syngas stream obtained by gasification of carbonaceous feed material, where the raw syngas stream optionally contain tars, and comprises hydrogen and carbon monoxide, as well as at least one light hydrocarbon consisting of methane and/or hydrocarbons containing 2 or 3 carbon atoms; and (B1) adding oxygen to raw syngas stream while imparting heat to raw syngas stream, and partially oxidizing light hydrocarbons to increase amounts of hydrogen and carbon monoxide while converting tars if present to lower molecular weight products.    USE - The method is useful for: syngas treatment (claimed); and producing liquid transportation fuels comprising alcohols and diesel.    ADVANTAGE - The method: enhances efficiency of production of liquid transportation fuels from syngas; reduces capital cost and system complexity; is more attractive for retrofit installations; and increases yield of the bio fuel yield for given amount of biomass.    DETAILED DESCRIPTION - Method (M1) of syngas treatment, comprises: (A1) providing a raw syngas stream obtained by gasification of carbonaceous feed material, where the raw syngas stream optionally contain tars, and comprises hydrogen and carbon monoxide as well as at least one light hydrocarbon consisting of methane and/or hydrocarbons containing 2 or 3 carbon atoms; and (B1) adding oxygen to the raw syngas stream while imparting heat to the raw syngas stream at a rate greater than 125 British thermal unit (BTU) per pound of oxygen added, and partially oxidizing the light hydrocarbons to increase the amounts of hydrogen and carbon monoxide in the syngas while converting tars if present to lower molecular weight products including hydrogen and carbon monoxide. An INDEPENDENT CLAIM is also included for method (M2) of syngas treatment, comprising generating the raw syngas stream by gasification of carbonaceous feed material, and treating the raw syngas stream by the method (M1) and step (B1) as above per se.