TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Components: The sequences encoding the acylating aldehyde dehydrogenase, the keto-thiolase or acetyl-CoA acetyltransferase, the acetoacetyl-CoA reductase or hydroxybutyryl-CoA dehydrogenase, the crotonase, the crotonyl-CoA reductase, butyryl-CoA dehydrogenase or trans-enoyl-CoA reductase, and the butyraldehyde/butanol dehydrogenase are optionally linked. The sequences encoding the pyruvate:flavodoxin/ferredoxin-oxidoreductase, the keto-thiolase or acetyl-CoA acetyltransferase, the acetoacetyl-CoA reductase or hydroxybutyryl-CoA dehydrogenase, the crotonase, the crotonyl-CoA reductase, butyryl-CoA dehydrogenase or trans-enoyl-CoA reductase, and the butyraldehyde/butanol dehydrogenase are optionally linked. The recombinant cell (C1) further comprises a recombinant sequence encoding a pyruvate decarboxylase catalyzing the conversion of pyruvate to acetaldehyde. The pyruvate decarboxylase is derived from Z. mobilis or S. cerevisiae. The pyruvate:flavodoxin/ferredoxin-oxidoreductase is derived from E. coli, S. cerevisiae, E. faecalis, or Z. mobilis. The acylating aldehyde dehydrogenase is derived from E. coli. The acylating aldehyde dehydrogenase is (EutE). The keto-thiolase or acetyl-CoA acetyltransferase is derived from E. coli, R. eutrophus, A. caviae, T. denticola or C. acetobutylicum. The keto-thiolase or acetyl-CoA acetyltransferase is (PhaA), (AtoB), (FadA), or (Thl). The acetoacetyl-CoA reductase or hydroxybutyryl-CoA dehydrogenase is derived from E. coli, R. eutrophus, A. caviae, T. denticola, or C. acetobutylicum. The acetoacetyl-CoA reductase or hydroxybutyryl-CoA dehydrogenase is (Hbd) or (PhaB). The crotonase is derived from E. coli, R. eutrophus, A. caviae, T. denticola, or C. acetobutylicum. The crotonase is (Crt) or (PhaJ). The crotonyl-CoA reductase, butyryl-CoA dehydrogenase or trans-enoyl-CoA reductase is derived from E. coli, R. eutrophus, A. caviae, T. denticola, C. acetobutylicum or S. collinus. The crotonyl-CoA reductase, butyryl-CoA dehydrogenase, or trans-enoyl-CoA reductase is (Ter) or (Ccr). The butyraldehyde/butanol dehydrogenase is derived from E. coli, R. eutrophus, A. caviae, T. denticola, or C. acetobutylicum. The butyraldehyde/butanol dehydrogenase is (Bed), (Aad), or alcohol dehydrogenase (AdhE2). The pyruvate decarboxylase is (Pdc) from Z. mobilis, the acylating aldehyde dehydrogenase is (EutE) from E. coli, the keto-thiolase is (PhaA) from R. eutrophus, the hydroxybutyryl-CoA dehydrogenase is (Hbd) from C. acetobutylicum, the crotonase is (Crt) from C. acetobutylicum, the crotonyl-CoA reductase is (Ter) from T. denticola, and the alcohol dehydrogenase is (AdhE2) from C. acetobutylicum and the recombinant cell is a S. cerevisiae cell or E. coli cell. The pyruvate:flavodoxin/ferredoxin-oxidoreductase is YdbK from E. coli, the keto-thiolase is (PhaA) from R. eutrophus, the hydroxybutyryl-CoA dehydrogenase is (Hbd) from C. acetobutylicum, the crotonase is (Crt) from C. acetobutylicum, the crotonyl-CoA reductase is (Ter) from T. denticola, and the alcohol dehydrogenase is (AdhE2) from C. acetobutylicum and the recombinant cell is S. cerevisiae cell or E. coli cell. The recombinant cell further comprises recombinant sequences encoding the ferredoxin-NADP reductase from E. coli, the ferredoxin FdC from E. coli, and the flavodoxins FldA and FldB from E. coli. The acetoacetyl-CoA reductase is the C. acetobutylicum acetoacetyl-CoA reductase Hbd and crotonase is the C. acetobutylicum crotonase Crt. The 3-hydroxybutyryl-CoA dehydrogenase is the R. eutrophus 3-hydroxybutyryl-CoA dehydrogenase phaB and the crotonase is the A. caviae crotonase PhaJ. The acetyl-CoA acetyltransferase is the R. eutrophus acetyltransferase (PhaA), the 3-hydroxybutyryl-CoA dehydrogenase is the R. eutrophus 3-hydroxybutyryl-CoA dehydrogenase (phaB), the crotonase is the A. caviae crotonase (PhaJ) and the transenoyl-CoA reductase is the T. denticola transenoyl-CoA reductase (Ter). The recombinant cell (C1) further comprises a recombinant sequence encoding a pantothenate kinase catalyzing the conversion of pantothenate to 4'-phosphopantothenate. The pantothenate kinase is derived from E. coli, and is (PanK), (CoaA), or (CoaX). The recombinant cell further comprises a recombinant sequence encoding a phosphopantothenoylcysteine synthetase catalyzing the conversion of 4'-phosphopantothenate to 4'-phosphopantothenoylcysteine. The phosphopantothenoylcysteine synthetase is derived from E. coli, and is (Ppcs) or (CoaB). The recombinant cell further comprises a recombinant sequence encoding phosphopantothenonylcysteine decarboxylase catalyzing the conversion of 4'-phosphopantothenoylcysteine to 4'-phosphopantetheine. The phosphopantothenonylcysteine decarboxylase is derived from E. coli, and is Ppcdc or CoaC. The recombinant cell further comprises a recombinant sequence encoding phosphopantetheine adenylyl transferase catalyzing the transfer of an adenylyl group from ATP to 4'-phosphopantetheine. The phosphopantetheine adenylyl transferase is derived from E. coli, and is (Ppat) or (CoaD). The recombinant cell further comprises a recombinant sequence encoding dephosphocoenzyme A kinase catalyzing the phosphorylation of dephospho-CoA. The dephosphocoenzyme A kinase is derived from E. coli, and is (CoaE). The cell is a prokaryotic cell or a eukaryotic cell. The cell is a proteobacterial, archaebacterial, bacteroidal, enterobacterial, spirochetal, mammalian, insect, fungal, yeast, E. coli, Z. mobilis, B. subtilis, S. cerevisiae, S. pombe, Synechocystis sp., Synechococcus sp., Rhodospirillum sp., Ralstonia sp., Pseudomonas sp., Rhodococcus sp., T. saccharolyticum, Thermotoga sp., T. reesei, A. niger, P. chrysosporium, Chinese hamster ovary (CHO) cell, or SF9 cell. Preferred Method: The recombinant sequences encoding the enzymes require 4 moles of NADH, or 3 moles of NADH and 1 mole of NADPH for the production of one mole of n-butanol. The activity of a lactate dehydrogenase catalyzing the conversion of pyruvate to lactate is reduced or eliminated. The pyruvate oxidase is (LdhA). The activity of a pyruvate oxidase catalyzing the conversion of pyruvate to acetate is reduced or eliminated. The pyruvate oxidase is PoxB. The activity of an alcohol dehydrogenase catalyzing the conversion of acetyl-CoA to ethanol is reduced or eliminated. The alcohol dehydrogenase is AdhE2. The activity of an acetate kinase catalyzing the conversion of acetyl-CoA to acetate is reduced or eliminated. The acetate kinase is (AckA). The activity of a phosphotransacetylase catalyzing the conversion of acetyl-CoA to acetate is reduced or eliminated. The phosphotransacetylase is (Pta). In the process (M1): the recombinant cell is grown under microaerobic conditions, or anaerobic conditions. The recombinant cell is grown under conditions where the cell produces elevated levels of n-butanol compared to a wild-type cell. The cell (C1) produces at least 4 g/l n-butanol. The recombinant cell is an E. coli cell. EXAMPLE - No suitable example is given.