TECHNOLOGY FOCUS - BIOLOGY - Preferred Method: The method further comprises: drying the treated lignocellulosic biomass; and pyrolyzing the treated lignocellulosic biomass to obtain a bio-oil product with a high sugar yield. The pyrolyzing is carried out at 300-500 degrees C. The treating is carried out with 0.04-0.5 mmol mineral acid/g of biomass. The pyrolyzing is carried out in a continuous flow reactor or in an auger-type reactor, where the pyrolyzed bio-oil from the auger-type reactor product comprises 15-30 wt.% sugar. Preferred Components: The obtained bio-oil product comprises anhydrosugars, monosaccharides and oligosaccharides. The lignocellulosic biomass is softwood, hardwood, grasses and/or crop residues. The molar concentration of AAEM salts in the acid-treated lignocellulosic biomass is 0.065-0.4 mmol/g of biomass. The mineral acid is sulfuric acid, phosphoric acid or hydrochloric acid. EXAMPLE - The structural composition of biomass (red oak and loblolly pine) was determined by extracting the cell wall of biomass and analyzing the content of cellulose, hemicellulose and lignin. Biomass sample (500 g) was dried and milled to 212-500 mu m size. The plant material was homogenized in 80 vol.% ethanol using a at high speed for 2-3 minutes. Homogenate was heated for 1 hour at 80 degrees C, cooled down to room temperature, and centrifuged at 12000 times gravity for 30 minutes. Pellets were resuspended in 80% ethanol, and the procedure was repeated. Pellets were washed 3 times with 85% acetone, and air dried. Dry pellets were suspended in 0.5% aqueous sodium dodecyl sulfate overnight. The residue was recovered and washed with water by filtration, washed with a 1:1 mixture of chloroform and methanol, rinsed with acetone, and air-dried. The resulting cell wall material was analyzed. Then the AAEM content of the feedstocks was determined using an inductively coupled plasma spectrometer with the standard acid digestion method ASTM D6349. Then the biomass was subjected to pyrolysis by grinding. The resulting ground feedstock was sieved. Five acids (phosphoric, sulfuric, nitric, hydrochloric, acetic and formic acids) were infused into the biomass at five different loadings (0.5, 1,2, 5 and 10 wt.%). Acid was dissolved in 15 g of water before mixing with a 5 g biomass sample in a 250 ml beaker to ensure a uniform infusion of the acid into the biomass. The damp biomass was then dried in an oven at 50 degrees C to the same moisture content as the original biomass. Analytical pyrolysis of pretreated biomass was performed using a Frontier lab double shot micropyrolyzer. Pyrolysis was carried out at 500 degrees C with a 320 degrees C interface temperature. The volatile products were swept from the micropyrolyzer directly to the 300 degrees C gas chromatography injector using 1 ml/minute of helium as a carrier gas. The column oven was started at 45 degrees C and ramped to 300 degrees C at 5 degrees C/minute, to obtain the bio-oil product.