NOVELTY - Producing bio-mass derived high-octane fuel involves (a) fermenting biomass with microorganism or its mutagen to produce mixture of metabolites containing acetone and butanol; (b) separating the acetone from butanol and any ethanol or other solvents in the mixture; (c) dimerizing a portion of resultant acetone from step (b) to form isopentane; (d) trimerizing another portion of the acetone from step (b) using a catalyst containing metal selected from niobium, iron, and manganese to form mesitylene, and (e) mixing the mesitylene with the isopentane from steps (c) and (d).    USE - For producing bio-mass derived high-octane fuel (claimed). Also useful for high-octane, rocket, diesel, turbine engine fuels, and two-cycle, spark-ignited engine fuels, aircraft.    ADVANTAGE - The method exhibits significantly higher octane numbers and increased energy per unit volume when compared to commercial fuels and ethanol-based fuels; and provides fully renewable fuels, high energy renewable fuels.    DETAILED DESCRIPTION - Producing bio-mass derived high-octane fuel involves (a) fermenting a biomass with microorganism or its mutagen to produce a mixture of metabolites containing acetone and butanol, (b) separating the acetone from butanol and any ethanol or other solvents in the mixture by fractional distillation, (c) dimerizing a portion of resultant acetone from step (b) to form isopentane, (d) trimerizing another portion of the acetone from step (b) using a catalyst containing at least one metal selected from niobium, iron, and manganese to form mesitylene, and (e) mixing the mesitylene with the isopentane from steps (c) and (d); or (a2) fermenting a biomass with a microorganism or its mutagen to produce a mixture of metabolites containing ethanol (E1), (b2) carrying out a dehydration reaction of ethanol in the presence of a zinc oxide catalyst on a calcium base at elevated temperatures of 350 degrees C and at elevated pressures, and (c2) cooling vapors from the dehydration reaction to condense water and separate unreacted ethanol to acetone through distillation to form the resultant mesitylene; or (a3) growing saccharophagus degradans, strain 2-40, in a first portion of plant material, or (b3) harvesting protein from saccharophagus degradans, strain 2-40 from the first portion of plant material, (c3) mixing the protein with a second portion of the plant material and yeast in an aqueous mixture, by producing ethanol (E2), (d3) converting the ethanol in whole or in part to acetone, (e3) separating the acetone from any remaining ethanol and/or other byproducts, (f3) dimerizing a portion of the acetone from step (e3) to form isopentane, (g3) trimerizing another portion of the acetone from step (e3) using a catalyst containing at least one metal selected from niobium, iron, and manganese to form mesitylene, and (h3) mixing the mesitylene with the isopentane from steps (b3) and (c3), where forms the biomass-derived high-octane fuel.