Succinic acid biosynthesis by Corynebacterium glutamicum

Abstract

Succinic acid is one of the most desirable raw materials. Currently, it is obtained mainly by hydrogenation of maleic acid derived from the C4 petroleum fraction. Corynebacterium glutamicum is considered as a possible microbiological producer of this acid. Under oxygen deprivation conditions this bacteria secretes L-lactate, succinate and acetate. Succinic acid is an intermediate of the Krebs cycle, in order to achieve high efficiency of its biosynthesis, metabolic engineering of C. glutamicum is required. The best producers described so far are C. glutamicum R ΔldhA pCRA717 (146 g/L) and C. glutamicum BOL-3/pAN6-gap (133 g/L). Succinic acid biosynthesis can also be achieved under aerobic conditions. C. glutamicum ZX1 (pEacsAgltA) produces aerobically 21.7 g/L of succinate. Genetic engineering is also necessary to enable the use of low-cost, waste carbon source such as glycerol or starch. The paper also presents and discusses examples of modifications of bacterial cells, allowing them to use these two carbon sources.