NOVELTY - Production of a bioproduct, comprises: (a) culturing a microorganism that produces the bioproduct in a bioreactor that comprises a fermentable feedstock, where the microorganism ferments the feedstock to produce the bioproduct; (b) heating the fermentation broth; (c) distilling the heated fermentation broth under pressure to produce a vapor that comprises the bioproduct, where the vapor that comprises the bioproduct is separated from whole stillage; (d) condensing the vapor, thus producing a condensate that comprises the bioproduct; and (e) recovering the bioproduct from the condensate.    USE - The methods and system are useful for producing a bioproduct, preferably butanol and/or crotyl alcohol; and for separating acetone from other solvents (all claimed).    ADVANTAGE - The methods and system greatly reduce energy consumption and enable the conversion of low cost feedstocks such as corn fiber.    DETAILED DESCRIPTION - Production of a bioproduct, involves: (a) culturing a microorganism that produces the bioproduct in a bioreactor that comprises a fermentable feedstock, where the microorganism ferments the feedstock to produce the bioproduct, thus producing a fermentation broth that comprises the bioproduct; (b) heating the fermentation broth; (c) distilling the heated fermentation broth under pressure to produce a vapor that comprises the bioproduct, where the vapor that comprises the bioproduct is separated from whole stillage; (d) condensing the vapor, thus producing a condensate that comprises the bioproduct; and (e) recovering the bioproduct from the condensate. INDEPENDENT CLAIMS are included for:    (1) a method for producing butanol and/or crotyl alcohol, which involves: (a) culturing a microorganism that produces butanol and/or crotyl alcohol, and acetone, in a bioreactor that comprises fermentable feedstock, where the microorganism ferments the feedstock to produce the butanol and/or crotyl alcohol, and acetone, thus producing a fermentation broth that comprises butanol and/or crotyl alcohol, and acetone; (b) heating the fermentation broth; (c) producing a first vapor that comprises butanol and/or crotyl alcohol, and acetone, where the first vapor is separated from whole stillage; (d) separating a butanol and/or crotyl alcohol-containing liquid and an acetone-containing second vapor from the first vapor in a rectifier; and (e) recovering butanol and/or crotyl alcohol from the butanol and/or crotyl alcohol-containing liquid;    (2) a continuous reflux distillation system for separating acetone from other solvents, which comprises: (a) a feed that comprises acetone, water and other solvents; (b) a first distillation column that comprises a top portion and a bottom portion;(c) an inlet through which feed is introduced into the first distillation column; and (d) a side draw that is at a location between the top portion and the bottom portion of the column and at a location that is higher in the column than the feed inlet; where when the first distillation column is operated under conditions that are suitable for distillation and separation of acetone from the other solvents, acetone-rich vapor exits through an outlet in the top portion of the column and a mixed solvent stream that comprises a lower concentration of acetone than the acetone-rich vapor exits through the side draw; and    (3) a method for separating acetone from other solvents, which involves: (a) conducting a feed that comprises acetone, water, and other solvents through an inlet into a first distillation column that comprises a top portion, a bottom portion, and a side draw that is at a location that is higher in the column than the feed inlet; (b) operating the first distillation column under conditions that are suitable for distillation and separation of the acetone from the other solvents; and (c) recovering acetone-rich vapor through an outlet in the top portion of the column and recovering a mixed solvent stream that comprises a lower concentration of acetone and the acetone-rich vapor through the side draw, and where the first distillation column is operated as a continuous reflux distillation system.