Butanol tolerance in microorganisms

A recombinant yeast microorganism comprising a pyruvate utilizing biosynthetic pathway, wherein the pyruvate utilizing biosynthetic pathway is an isobutanol biosynthetic pathway comprising heterologous DNA molecules encoding polypeptides that catalyze the following substrate to product conversions:

• a) pyruvate to acetolactate;
• b) acetolactate to 2,3-dihydroxyisovalerate;
• c) 2,3-dihydroxyisovalerate to α-ketoisovalerate;
• d) α-ketoisovalerate to isobutyraldehyde;
• and
• e) isobutyraldehyde to isobutanol;
• and
• wherein the recombinant yeast microorganism further comprises a first genetic modification, wherein the first genetic modification is a deletion or disruption in at least one endogenous gene encoding a pyruvate decarboxylase enzyme, wherein the deletion or disruption eliminates pyruvate decarboxylase activity, and
• wherein the recombinant yeast microorganism further comprises a second genetic modification, wherein the second genetic modification is a substitution mutation in an adenylate cyclase gene, wherein the substitution mutation is at a residue equivalent to A1814 or H1873 of SEQ ID NO:1 and wherein the adenylate cyclase gene encodes a polypeptide having at least 90% sequence identity to SEQ ID NO:1.