NOVELTY - Recombinant microorganism comprising (a) a butanol biosynthetic pathway comprising at least one polypeptide that is heterologous to the recombinant microorganism, (b) a heterologous glycerol-3-phosphate dehydrogenase (GPD), where the heterologous GPD has a higher K(m) for NADH as compared to the K(m) of the endogenous GPD of the microorganism, and (c) a deletion or disruption in an endogenous gene encoding GPD is new.    USE - The recombinant microorganism is useful for producing isobutanol (claimed) which is used as fuels (e.g. biofuels), a fuel additive, producing esters for diesel or biodiesel production, and as a solvent for paints, coatings, varnishes, resins, gums, dyes, fats, waxes, resins, shellac, rubbers, and alkaloids.    ADVANTAGE - The recombinant microorganism: has improved production of butanol as compared to a control recombinant microorganism that lacks the heterologous glycerol-3-phosphate dehydrogenase; has decreased production of glycerol as compared to a control recombinant microorganism that lacks the heterologous glycerol-3-phosphate dehydrogenase; and has an increased butanol to glycerol molar ratio as compared to a control recombinant microorganism that lacks the heterologous glycerol-3-phosphate dehydrogenase (all claimed).    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) an engineered GPD enzyme having at least 85% identity to of SEQ ID NO: 195 (comprising a fully defined sequence of 391 amino acids as given in the specification);    (2) a recombinant microorganism comprising the engineered GPD enzyme;    (3) producing isobutanol, comprising providing the recombinant microorganism comprising an engineered isobutanol biosynthetic pathway, a deletion or disruption in an endogenous gene encoding GPD1, and at least one of the engineered GPD enzyme or a heterologous GPD, where the heterologous GPD has a higher K(m) for NADH as compared to the K(m) of the microorganism's endogenous GPD, and contacting the recombinant microorganism with at least one fermentable carbon substrate under conditions, where isobutanol is produced; and    (4) a recombinant microorganism comprising (b) and (c) as above per se, where the recombinant microorganism has decreased production of glycerol as compared to a control recombinant microorganism that lacks the heterologous GPD.