TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Substrate: The fermentable carbon substrate is chosen from monosaccharides, oligosaccharides, and polysaccharides. Preferred Polypeptide: The polypeptide that catalyzes a substrate to product conversion of pyruvate to alpha -acetolactate is acetolactate synthase. The polypeptide that catalyzes a substrate to product conversion of alpha -acetolactate to acetoin is acetolactate decarboxylase. The polypeptide that catalyzes a substrate to product conversion of acetoin to 3-amino-2-butanol is acetoin aminase. The polypeptide that catalyzes a substrate to product conversion of 3-amino-2-butanol to 3-amino-2-butanol phosphate is aminobutanol kinase. The polypeptide that catalyzes a substrate to product conversion of 3-amino-2-butanol phosphate to 2-butanone is aminobutanol phosphate phospholyase. The polypeptide that catalyzes a substrate to product conversion of 2-butanone to 2-butanol is butanol dehydrogenase. The acetolactate synthase has an amino acid sequence having at least 95% identity to an amino acid sequence chosen from a 559 amino acid sequence (SEQ ID NO: 4 or 79) fully defined in the specification, and a 540 amino acid sequence (SEQ ID NO: 77) fully defined in the specification, based on the Clustal W method of alignment using the default parameters of GAP PENALTY (that is 10), GAP LENGTH PENALTY (that is 0.1), and Gonnet 250 series of protein weight matrix. The acetolactate decarboxylase has an amino acid sequence having at least 95% identity to an amino acid sequence chosen from a 259 amino acid sequence (SEQ ID NO: 2 or 83) fully defined in the specification, and a 255 amino acid sequence (SEQ ID NO: 81) fully defined in the specification, and based on the Clustal W method of alignment using the default parameters of GAP PENALTY, GAP LENGTH PENALTY, and Gonnet 250 series of protein weight matrix. The acetoin aminase has an amino acid sequence having at least 95% identity to a 453 amino acid sequence (SEQ ID NO: 122) fully defined in the specification based on the Clustal W method of alignment using the default parameters of GAP PENALTY, GAP LENGTH PENALTY, and Gonnet 250 series of protein weight matrix. The aminobutanol kinase has an amino acid sequence having at least 95% identity to a 374 amino acid sequence (SEQ ID NO: 124) fully defined in the specification, based on the Clustal W method of alignment using the default parameters of GAP PENALTY, GAP LENGTH PENALTY, and Gonnet 250 series of protein weight matrix. The aminobutanol phosphate phospholyase has an amino acid sequence having at least 95% identity to a 424 amino acid sequence (SEQ ID NO: 126) fully defined in the specification, based on the Clustal W method of alignment using the default parameters of GAP PENALTY, GAP LENGTH PENALTY, and Gonnet 250 series of protein weight matrix. The butanol dehydrogenase has an amino acid sequence having at least 95% identity to an amino acid sequence chosen from a 346 amino acid sequence (SEQ ID NO: 14) fully defined in the specification, a 251 amino acid sequence (SEQ ID NO: 72) fully defined in the specification, a 387 amino acid sequence (SEQ ID NO: 75) fully defined in the specification, and a 234 amino acid sequence (SEQ ID NO: 91) fully defined in the specification, based on the Clustal W method of alignment using the default parameters of GAP PENALTY, GAP LENGTH PENALTY, and Gonnet 250 series of protein weight matrix. Preferred Cell: The cell is chosen from bacterium, Cyanobacterium, filamentous fungus and yeast that are belonging to genus chosen from Clostridium, Zymomonas, Escherichia, Salmonella, Rhodococcus, Pseudomonas, Bacillus, Lactobacillus, Enterococcus, Pediococcus, Alcaligenes, Klebsiella, Paenibacillus, Arthrobacter, Corynebacterium, Brevibacterium, Pichia, Candida, Hansenula and Saccharomyces. EXAMPLE - No suitable example given.