Establishing a Synthetic Pathway for Production of Gamma-butyrolactone in Mannheimia succiniciproducens

Abstract

γ-Butyrolactone (GBL) is an important four carbon (C4) chemical, whichhas a wide range of industrial applications. GBL can be produced by acidtreatment of 4-hydroxybutyric acid (4-HB), which is a derivative of succinicacid. Heterologous metabolic pathways were designed and established insuccinic acid overproducing M. succiniciproducens LPK7(ldhA pflD pta ackAmutant) by the introduction of heterologous genes that encode succinyl-CoAsynthetase, CoA-dependent succinate semialdehyde dehydrogenase, and either4-hydroxybutyrate dehydrogenase in LPK7 (p3S4CD) or succinatesemialdehyde reductase in LPK7 (p3SYCD). Fed-batch cultures of LPK7(p3S4CD) and LPK7 (p3SYCD) resulted in the production of 6.37 and 6.34g/L of 4-HB, respectively. Finally, GBL was produced by acid treatment ofthe 4-HB obtained from the fermentation broth. This study demonstrates that4-HB, and potentially other four carbon platform chemicals, can be producedby the engineered rumen bacterium M. succiniciproducens. (Development ofsystems metabolic engineering platform technologies for biorefineries funded by the Ministry ofEducation, Science and Technology)