The invention provides a non-naturally occurring microbial organism having 4-hydroxybutanoic acid (4-HB) and 1,4-butanediol (1,4-BDO) biosynthetic pathways. The pathways include exogenous nucleic acids encoding a) an α-ketoglutarate decarboxylase; b) a 4-hydroxybutanoate dehydrogenase; c) a 4-hydroxybutyryl-CoA:acetyl-CoA transferase or a butyrate kinase and a phosphotransbutyrylase; d) an aldehyde dehydrogenase, and e) an alcohol dehydrogenase, wherein the exogenous nucleic acids are expressed in sufficient amounts to produce 1,4-butanediol (1,4-BDO). Also provide is a method for the production of 1,4-BDO. The method includes culturing the non-naturally occurring microbial organism having 4-HB and 1,4-BDO biosynthetic pathways substantially anaerobic conditions for a sufficient period of time to produce 1,4-BDO.