TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Process: The process is conducted in: the fermentor; or a vessel external to the fermentor.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: In the process: during or after separating step, production of the butanol product in the fermentation broth continues; after separating step, the aqueous phase or its portion is returned to the fermentor; and after butanol recovery, the ionic liquid is recycled to the fermentation broth. The process further comprises mixing the recovered butanol with a motor fuel. Preferred Components: The ionic liquid comprises a cation comprising 1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-(N,N,N-dimethyl(methylethoxy)aminoethyl)-5-methylpyrrolidin-2-one, 1-(N,N,N-dimethylpropylaminoethyl)-5-methylpyrrolidin-2-one, 1-(N,N,N-dimethyl (hydroxyethyl)aminoethyl)-5-methylpyrrolidin-2-one or 1-(N,N,N-dimethyl(ethylethoxy)aminoethyl)-5-methylpyrrolidin-2-one. The ionic liquid is: 1-ethyl-3-methylimidazolium levulinate, 1-(N,N,N-dimethyl(ethylethoxy)aminoethyl)-5-methylpyrrolidin-2-one hexafluoropropane sulfonate, 1-(N,N,N-dimethyl(ethylethoxy)aminoethyl)-5-methyl pyrrolidin-2-one bis (trifluoromethane)sulfonamide, 1-(N,N,N-dimethyl(methylethoxy)aminoethyl)-5-methylpyrrolidin-2-one hexafluoropropane sulfonate, 1-butyl-3-methylimidazolium levulinate, 1-(N,N,N-dimethylpropylaminoethyl)-5-methylpyrrolidin-2-one bis(trifluoromethane)sulfonamide, 1-(N,N,N-dimethyl(methylethoxy)aminoethyl)-5-methylpyrrolidin-2-one bis(trifluoromethane)sulfonamide or 1-(N,N,N-dimethyl(hydroxyethyl)aminoethyl)-5-methylpyrrolidin-2-one bis(trifluoromethane)sulfonamide; or 1-(N,N,N-dimethyl(ethylethoxy)aminoethyl)-5-methylpyrrolidin-2-one bis(trifluoromethane)sulfonamide, 1-(N,N,N-dimethylpropylaminoethyl)-5-methylpyrrolidin-2-one bis(trifluoromethane)sulfonamide, 1-(N,N,N-dimethyl(methylethoxy)aminoethyl)-5-methylpyrrolidin-2-one bis(trifluoromethane)sulfonamide or 1-(N,N,N-dimethyl( hydroxyethyl)aminoethyl)-5-methylpyrrolidin-2-one bis(trifluoromethane)sulfonamide. EXAMPLE - Stock culture of Lactobacillus fermentum ATCC 14931 was grown and placed them in sterile polypropylene test tube (15 ml) containing 3 ml of MRS media (Lactobacillus MRS Broth). The test tube was incubated at 30 degrees C at 175 rpm. After four hours, the culture tube was inoculated with 1-ethyl-3-methylimidazolium levulinate (150 mu l), and again the culture tube was incubated under the same conditions for another 16 hours. Then the sample from the culture tube was subjected to spinning at 28000 rpm and 20 degrees C for ten minutes in a centrifuge, and supernatant (1 ml) was removed from the tube and the reaction mixture was worked up. Then alcohol was separated to the ionic liquid phase from the aqueous phase, and recovered.