Butanol strain improvement with integration of a polynucleotide encoding a polypeptide that catalyzes pyruvate to acetolactate conversion

A method comprising:

• (a) providing a recombinant host cell comprising an isobutanol biosynthetic pathway wherein said pathway comprises the substrate to product conversion pyruvate to acetolactate catalyzed by a polypeptide encoded by a heterologous polynucleotide integrated into the chromosome at the PDC1-TRX1 intergenic region and wherein said pathway comprises the substrate to product conversion acetolactate to 2,3-dihydroxyisovalerate catalyzed by a polypeptide that has at least about 90% identity to SEQ ID NO:
• 224 or 225 and said polypeptide is encoded by a polynucleotide on a plasmid and wherein the titer of isobutanol production is increased as compared to a recombinant host cell wherein the polynucleotide encoding a polypeptide that catalyzes the conversion of pyruvate to acetolactate is not integrated into the chromosome;
• (b) contacting the host cell with a fermentable carbon substrate to form a fermentation broth under conditions whereby the isobutanol biosynthetic pathway product is produced;
• and
• (c) contacting the fermentation broth with an extractant to produce a two-phase fermentation mixture, wherein the extractant comprises fatty acids;
• and
• (d) recovering the isobutanol.