l -Malate Production by Metabolically Engineered Escherichia coli

Abstract

Escherichia coli strains (KJ060 and KJ073) that were previously developed for succinate production have now been modified for malate production. Many unexpected changes were observed during this investigation. The initial strategy of deleting fumarase isoenzymes was ineffective, and succinate continued to accumulate. Surprisingly, a mutation in fumarate reductase alone was sufficient to redirect carbon flow into malate even in the presence of fumarase. Further deletions were needed to inactivate malic enzymes (typically gluconeogenic) and prevent conversion to pyruvate. However, deletion of these genes (

Manipulation of the ATP pool as a tool for metabolic engineering

“…For example, using either malic enzyme or PEP carboxykinase (acting in the carboxylating and thus opposite direction of the typical decarboxylating activity) instead of pyruvate carboxylase increases the overall ATP yield by one ATP per C3[EPS]C4 carboxylation event. These replacements enable anaerobic malic acid production and increase the ATP yield for redox-neutral succinic acid production significantly [15,[30][31][32][33].…”

Design and Construction of a Non-Natural Malate to 1,2,4-Butanetriol Pathway Creates Possibility to Produce 1,2,4-Butanetriol from Glucose

“…In terms of the availability of malate, not all malate enters the BT biosynthetic pathway. It has been reported malate can not only be converted to fumarate by native fumarate hydratase, which can further be reduced to succinate by native fumarate reductase, but also can be converted to pyruvate by native malate dehydrogenase under oxygen-limited cultivation conditions in E. coli 513. Therefore, these competitive reactions of malate substrate would be blocked.…”

“…It is also necessary to improve the malate production from glucose for the better performance of the entire glucose to BT pathway, and this work has partially been done by other scholars in E. coli. To date, its highest titer and yield reported is 34 g/L and 1.42 mol/mol glucose, respectively5. Potential still exists therefore for improving the production of BT from malate or glucose.…”

“…Glucose has been widely used as a cheap feedstock for producing bulk chemicals45678910, and can be efficiently metabolized through the tricarboxylic acid (TCA) cycle. Malate, one of the TCA intermediates, shares a similar structure with BT except for the two terminal groups (two carboxyl groups in malate, versus two hydroxyl groups in BT).…”

Metabolic engineering of Saccharomyces cerevisiae to improve succinic acid production based on metabolic profiling

“…16,17) The commercial market for succinic acid is 30,000-50,000 tons per year, expected to expand to 100,000 tons per year by 2015. 18) It has been reported that succinic acid production has been achieved using recombinant microorganisms, such as Escherichia coli [19][20][21][22][23][24][25][26] and Corynebacterium glutamicum. [27][28][29] Moreover, natural succinic acid-producing microorganisms have been isolated, including Actinobacillus succinogenes 30) and Mannheimia succiniciproducens.…”