TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The genetically modified microorganism is bacteria, cyanobacteria, filamentous fungi or yeasts, where the: bacteria is Zymomonas, Escherichia, Salmonella, Rhodococcus, Pseudomonas, Bacillus, Lactobacillus, Enterococcus, Pediococcus, Alcaligenes, Klebsiella, Paenibacillus, Arthrobacter, Corynebacterium or Brevibacterium; and yeast is Pichia, Candida, Hansenula, Kluyveromyces, Issatchenkia or Saccharomyces.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: In the method (I), a portion of the butanol is concurrently removed from the fermentation medium by a process comprising: stripping butanol from the fermentation medium with a gas to form a butanol-containing gas phase; and recovering butanol from the butanol-containing gas phase. The osmolyte: is added to the fermentation medium, to the first extractant and/or to the optional second extractant; and comprises polyethylene glycol, dextran, maize mash, starch, cellulose (all preferred), monosaccharide including sucrose, fructose and/or glucose, a disaccharide, glycerol, sugarcane juice, molasses and/or high fructose maize syrup. The first extractant is oleyl alcohol (preferred), behenyl alcohol, cetyl alcohol, lauryl alcohol, myristyl alcohol, stearyl alcohol, oleic acid, lauric acid, myristic acid, stearic acid, methyl myristate, methyl oleate, lauric aldehyde and/or 1-dodecanol and the second extractant is 1-nonanol, 1-decanol, 1-undecanol, 2-undecanol and/or 1-nonanal. The fermentation medium further comprises ethanol and the butanol-containing organic phase contains ethanol. In method (II), the osmolyte is added to: the aqueous phase during the growth phase of the microorganism; the aqueous phase during the butanol production phase; and the aqueous phase when the butanol concentration in the aqueous phase is inhibitory to the first extractant and/or the optional second extractant; and obtained from a fermentation carbohydrate substrate. In the method (III), where the osmolyte is added to the fermentation medium in step (c3): when the microorganism growth phase slows; and when the butanol production phase is complete. In the methods (I)-(III), the fermentable carbon source is present in the fermentation medium comprising renewable carbon from agricultural feedstocks, algae, cellulose, hemicellulose and/or lignocellulose. EXAMPLE - No suitable example given.