The hydrothermal conversions of three model compounds-starch, bovine serum albumin and linoleic acid-and their binary and ternary mixtures were evaluated. Batch experiments were operated at 250-350 degrees C, 5-20 MPa for 10-60 min. Bio-oil produced from sugars, proteins and their mixtures contained similar to 70% carbon and similar to 15% oxygen (w/w) with higher heating values than those of the substrates. When treated individually, bio-oil yields showed the following behavior: lipids > sugars > proteins. Dehydration and condensation reactions among intermediates were hypothesized to enhance the production of bio-oil via the hydrothermal conversion of sugar and lipid mixtures. The ternary mixtures (sugar + oil + protein) exhibit the best performance for bio-oil production, likely due to similar chemical reactions, catalyzed by alkalinity from protein degradation. Results of this study demonstrate that the bio-oil yields for hydrothermal liquefaction of sugars, proteins and lipids may be maximized by selective design of feed-stock composition. (C) 2016 Elsevier B.V. All rights reserved.