Development of chemically defined medium for Mannheimia succiniciproducens based on its genome sequence

Abstract

This study presents a novel methodology for the development of a chemically defined medium (CDM) using genome-scale metabolic network and flux balance analysis. The genome-based in silico analysis identified two amino acids and four vitamins as non-substitutable essential compounds to be supplemented to a minimal medium for the sustainable growth of Mannheimia succiniciproducens, while no substitutable essential compounds were identified. The in silico predictions were verified by cultivating the cells on a CDM containing the six non-substitutable essential compounds, and it was further demonstrated by observing no cell growth on the CDM lacking any one of the non-substitutable essentials. An optimal CDM for the enhancement of cell growth and succinic acid production, as a target product, was formulated with a single-addition technique. The fermentation on the optimal CDM increased the succinic acid productivity by 36%, the final succinic acid concentration by 17%, and the succinic acid yield on glucose by 15% compared to the cultivation using a complex medium. The optimal CDM also lowered the sum of the amounts of by-products (acetic, formic, and lactic acids) by 30%. The strategy reported in this paper should be generally applicable to the development of CDMs for other organisms, whose genome sequences are available.

Metabolic engineering of Corynebacterium glutamicum for L-arginine production

“…Major considerations include optimizing the culture medium 28 , resolving reduced mass transfer of nutrients in industrial-scale bioreactor 29 and reducing the separation and purification procedure of L-arginine by minimizing byproducts 30 . All these factors substantially affect the overall bioprocess costs, and therefore need to be systematically examined at large-scale, as in the case of pilot-scale cultivation of the AR6 strain conducted in this study.…”

Proteome-based physiological analysis of the metabolically engineered succinic acid producer Mannheimia succiniciproducens LPK7

“…The translational machinery proteins (FusA, Pnp, RpsA, SerS, MiaB, and ProS during exponential growth phase and Efp, Pnp, and RplJ during stationary phase) including initiation and ribosomal proteins, and lipid biosynthesis enzymes (AccC, and FabA during exponential growth phase) were known to have a proportional relationship with the cell growth rate [22,23] and, therefore, the levels were reduced in LPK7. The cell envelope proteins including MurF, which are associated [27] b Concentrations were normalized by consumed glucose concentration for more accurate comparison. SA succinic acid, PA pyruvic acid with cell division [24,25], also showed diminished level throughout the growth phase as the growth rate decreased in LPK7.…”

Engineered biosynthesis of biodegradable polymers

“…Availability of genome sequence of this bacterium also helped to develop a chemically defined medium (CDM) and use of this medium allowed 17 % increase in final succinic acid concentration, 36 % increase in productivity and 15 % increase in succinic acid yield as compared to complex medium. Additionally, by-product formation was reduced by 30 % [163].…”