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Metabolic Engineering of Mannheimia Succiniciproducens for the Production of Gamma-Butyrolactone

γ-Butyrolactone (GBL) is one of the most important chemicals, because it has a wide range of industrial applications. Because GBL is easily converted by acid treatment of 4-hydroxybutyric acid (4-HB), microbial overproduction of 4-HB followed by its chemical conversion can be a useful strategy for the biosynthesis of GBL. 4-HB can be produced in Mannheimia succiniciproducens LPK7 (ldhA, pflD, pta, and ackA mutant) by the introduction of heterologous genes that encode succinyl-CoA synthetase, CoA-dependent succinate semialdehyde dehydrogenase, and either 4-hydroxybutyrate dehydrogenase in LPK7 (p3S4CD) or succinate semialdehyde reductase in LPK7 (p3SYCD). LPK7 (p3S4CD) and LPK7 (p3SYCD) successfully produced 6.37 and 6.34 g/L of 4-HB, respectively, and GBL was finally obtained from chemical conversion of 4-HB. This study presents that the engineered rumen bacterium M. succiniciproducens can produce industrially valuable chemicals. [This work was supported by the Technology Development Program to Solve Climate Changes on Systems Metabolic Engineering for Biorefineries from the Ministry of Science, ICT and Future Planning (MSIP) through the National Research Foundation (NRF) of Korea (NRF-2012M1A2A2026556 and NRF-2012M1A2A2026557)]