TECHNOLOGY FOCUS - POLYMERS - Preferred Method: In method (M1), additionally at least part of the solid phase is removed from the biomass slurry prior to pumping of the liquid phase. The viscosity of the biomass slurry is modified prior to it being pumped into the pressurized gasifier by drying or by the addition of oils. The hydrocarbons obtained via recirculation of down-stream by-products, such as off gas are added together with the biomass to the pressurized gasifier. A slagging additive is added to the biomass slurry and the alkali-salts are removed from the biomass prior to its transfer into the pressurized gasifier. The alkali-salts are removed and collected together with sugars in a form suitable for nutritive additive to feeding stuff. The mixing of the polysaccharide containing biomass during liquefaction and hydrolysis performed under high-gravity conditions is relying on free fall mixers such as drum mixers, tumble mixers or similar mixing devices. The polysaccharide containing biomass slurry having a dry matter content of above 20% is subjected to a thermal pre-treatment including addition of chemicals inducing lignin degradation. The method (M1) is carried out as a batch, fed- batch, continuous or a similar process. Preferred Components: The liquid biomass slurry resulting from the enzymatic hydrolysis contains only particles less than 1 mm in size. The polysaccharide containing biomass slurry having a dry matter content of above 20% is derived from the biodegradable part of products, waste and remainders from agriculture (comprising compounds of both vegetable and animal origin) or forestry and closely related industries, or from the biodegradable part of waste from industry and household or is a lignocellulosic biomass or its part derived from agricultural crops consisting of e.g. corn stover, bagasse, straw e.g. from rice, wheat, oat, barley, rye, rape and sorghum, tubers e.g. beet, potato, cereals from e.g. rice, wheat, rye, oat, barley, rape, sorghum, wood consisting of softwood e.g. Pinus sylvestris, Pinus radiata, hardwood e.g. Salix spp., Eucalyptus spp. or municipal solid waste, waste paper, fiber fraction from processing of biogas, manure and similar biomasses or is a starch, e.g. starch containing grains or refined starch or is a mixture of starch and lignocellulosic biomasses. The dry matter content of the polysaccharide containing biomass after pre-treatment and liquefaction is 25-80%. EXAMPLE - Wheat straw (primarily a lignocellulose source) was pre-treated using counter-current water extraction at 180-200degreesC for 5-10 minutes, with water and dry matter flow ratio of 5:1. Wheat grain (primarily a starch source) was dry milled using a roller mill. The wheat grain and pre-treated straw with an average size of 40 mm was mixed in a 1:1 ratio on a dry basis. Dry Matter was adjusted to 30-40% by addition of water. Celluclast 1.5 FG L and Novozym 188 in a 5:1 ratio were added to give an enzyme loading of 7 FPU/g DM of straw. Hydrolysis of starch was carried out using cold mash enzyme NS50033 at a loading of 3.5 g/kg of wheat grain. The liquefaction and hydrolysis was performed at 50degreesC and pH of 4.8-5. Mixing straw with grain resulted in a fast liquefaction and accumulation of glucose compared to just applying straw only. Syngas was subsequently obtained by pumping the obtained liquefied biomass slurry into a slagging entrained flow gasifier. A plunger pump with special knife-edged spring-loaded cone valves was used to develop the required pressure. A constant flow of slurry to 26 bar pressurized gasifier chamber was maintained with a screw pump. The slurry was atomized pneumatically with pressurized pure oxygen. The produced syngas was free of tars and methane.