Metabolic engineering of Escherichia coli for production of L-aspartate and its derivative β-alanine with high stoichiometric yield
Autor: | Baixue Lin, Piao Xiaoyu, Yong Tao, Weifeng Liu, Lei Wang, Hao Chen |
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Rok vydání: | 2019 |
Předmět: |
0106 biological sciences
endocrine system diseases Bioconversion Carboxy-Lyases Glucose uptake Citric Acid Cycle Bioengineering 01 natural sciences Applied Microbiology and Biotechnology Metabolic engineering 03 medical and health sciences chemistry.chemical_compound Biosynthesis 010608 biotechnology Escherichia coli 030304 developmental biology Alanine 0303 health sciences Aspartic Acid Chemistry Futile cycle Escherichia coli Proteins nutritional and metabolic diseases Bioproduction Biochemistry Metabolic Engineering Yield (chemistry) beta-Alanine hormones hormone substitutes and hormone antagonists Biotechnology |
Zdroj: | Metabolic engineering. 54 |
ISSN: | 1096-7184 |
Popis: | L-aspartate is an important 4-carbon platform compound that can be used as the precursor of numerous chemical products. The bioproduction of L-aspartate directly from biomass resources is expected to provide a more cost-competitive technique route. Yet little metabolic engineering work on this matter has been carried out. In this study, we designed a shortcut pathway of L-aspartate biosynthesis in Escherichia coli, with a maximized stoichiometric yield of 2 mol/mol glucose. L-aspartate aminotransferase (AspC) was overexpressed for producing L-aspartate and coexpressed with L-aspartate-a-decarboxylase (PanD) for producing L-aspartate's derivative β-alanine. L-aspartate could only be detected after directing carbon flux towards oxaloacetate and blocking the “futile cycle” with TCA cycle. A cofactor self-sufficient system successfully improved the efficiency of AspC-catalyzing L-aspartate biosynthesis reaction, and the glucose uptake remolding capably decreased byproducts from pyruvate. More targets were modified for relieving the bottleneck during fed-batch bioconversion. As a result, 1.01 mol L-aspartate/mol glucose and 1.52 mol β-alanine/mol glucose were produced in corresponding strains respectively. Fed-batch bioconversion allowed 249 mM (33.1 g/L) L-aspartate or 424 mM (37.7 g/L) β-alanine production, respectively. The study provides a novel promising metabolic engineering route for the production of L-aspartate and its derivate chemicals using biomass resources. These results also represent the first report of the efficient bioproduction of L-aspartate directly from glucose in E. coli and the highest yield of β-alanine reported so far. |
Databáze: | OpenAIRE |
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