NOVELTY - Making a biofuel precursor comprises: (a) providing a biocatalyst selected to convert a feedstock into the biofuel precursor at a yield of at least 80% of theoretical, a productivity of at least 0.75 grams biofuel precursor/L/hour, and a titer equivalent to a lower one of (i) a solubility limit of the biofuel precursor in water under the process conditions and (ii) 2% (w/w) of the biofuel precursor in water; and (b) recovering the biofuel precursor.    USE - The methods are useful for making and producing a biofuel precursor (all claimed).    ADVANTAGE - The invention provides methods for the economical production of biofuel precursor that is also a biofuel from biomass.    DETAILED DESCRIPTION - Making a biofuel precursor comprises: (a) providing a biocatalyst selected to convert a feedstock into the biofuel precursor at a yield of at least 80% of theoretical, a productivity of at least 0.75 grams biofuel precursor/L/hour, and a titer equivalent to a lower one of (i) a solubility limit of the biofuel precursor in water under the process conditions and (ii) 2% (w/w) of the biofuel precursor in water; (b) providing the biocatalyst selected to have at least two properties selected from: (i) the biocatalyst selected to convert at least two sugars, including each of at least one of a six-carbon sugar and a six-carbon sugar oligomer, and at least one five-carbon sugar, derived from at least one of starch, cellulose, hemicellulose, and pectin into the biofuel precursor; (ii) the biocatalyst exhibiting a level of endotoxin toxicity or exotoxin toxicity, where the level of endotoxin or exotoxin toxicity in the biocatalyst has a median lethal dose (LD50) of at least 1000-fold more than the amount present in 1 kg of at least one of a distillers dried grains (DDG) and a distillers dried grains and soluble (DDGS) product; (iii) the biocatalyst containing no DNA markers; (iv) the biocatalyst operable to produce the biofuel precursor free of byproducts that would require additional processing steps for removal from the biofuel precursor; (v) the biocatalyst operable at a pH of 2-10 to produce the biofuel precursor; (vi) the biocatalyst selected to have a recoverable productivity from a sudden change of 1 pH unit from the first pH; (vii) the biocatalyst operable within a temperature of 20-60 degrees C to produce the biofuel precursor; (viii) the biocatalyst selected to have a recoverable productivity from a sudden change of 5 degrees C from the first temperature; (ix) the biocatalyst operable in a medium comprising feedstock; (x) the biocatalyst selected to have a growth rate of at least 0.2 per hour; (xi) providing a facultative anaerobic biocatalyst operable at dissolved oxygen concentrations across a range of 0-0.01% air saturation to produce the biofuel precursor; and (xii) providing an anaerobic biocatalyst selected to have a productivity that recovers from an exposure to more than 1% air saturation that lasts for up to three hours; and cultivating the biocatalyst in a culture medium until a recoverable quantity of the biofuel precursor is produced; and (c) recovering the biofuel precursor. INDEPENDENT CLAIMS are:    (1) a biofuel precursor produced by the method above, where the biofuel precursor comprises a 14C/12C ratio of 1:0 to 0:11;    (2) an isolated or recombinant biocatalyst comprising a recombinant biochemical pathway to produce isobutanol from fermentation of a suitable biomass, where the recombinant biochemical pathway comprises elevated activity of: (a) a Ketol-acid Reducto-Isomerase (KARI) as compared to a parental microorganism; and (b) an acetolactate synthase (ALS) as compared to a parental microorganism, where the biocatalyst produces recoverable amounts of isobutanol;    (3) an isolated or recombinant biocatalyst comprising a recombinant biochemical pathway to produce isobutanol from fermentation of a suitable biomass, where the recombinant biochemical pathway comprises decreased activity of: (a) a DHAD as compared to a parental microorganism; and (b) a kivd as compared to a parental microorganism, where the biocatalyst produces recoverable amounts of isobutanol;    (4) an isolated or recombinant biocatalyst comprising a recombinant biochemical pathway to produce isobutanol from fermentation of a suitable biomass, where the recombinant biochemical pathway comprises decreased activity of: (a) dihydroxyacid dehydratase (DHAD) as compared to a parental microorganism; and increased activity of: (b) ALS is broader as compared to a parental microorganism; and (c) KARI as compared to a parental microorganism;    (5) an isolated or recombinant nucleic acid comprising pLlacO1::alsS::ilvC::ilvD, p15A, and Cm;    (6) an isolated or recombinant nucleic acid comprising pLlacO1::kivd::ilvDco, pSC101, and Kan;    (7) an isolated or recombinant nucleic acid comprising PLlacO1::alsS::ilvCco, CoIE1, and Amp;    (8) an isolated or recombinant nucleic acid comprising pUacO1::pntAB, pSC101, and Kan; and    (9) a biocatalyst selected to convert a feedstock into the biofuel precursor at a yield of at least 80% theoretical yield, a productivity of at least 0.75 grams biofuel precursor/L/hour, and a titer equivalent to a lower one of (i) a solubility limit of the biofuel precursor in water under the process conditions and (ii) 2% (w/w) of the biofuel precursor in water; providing the biocatalyst selected to have the following properties: (a) the biocatalyst operable to produce the biofuel precursor free of byproducts that would require additional processing steps for removal from the biofuel precursor; and (b) the biocatalyst selected to have a growth rate of at least 0.2 per hour.