NDLI: Engineering Escherichia coli for high-level production of propionate

Content Provider	Springer Nature Link
Author	Akawi, Lamees Srirangan, Kajan Liu, Xuejia Moo Young, Murray Perry Chou, C.
Copyright Year	2015
Abstract	Mounting environmental concerns associated with the use of petroleum-based chemical manufacturing practices has generated significant interest in the development of biological alternatives for the production of propionate. However, biological platforms for propionate production have been limited to strict anaerobes, such as Propionibacteria and select Clostridia. In this work, we demonstrated high-level heterologous production of propionate under microaerobic conditions in engineered Escherichia coli. Activation of the native Sleeping beauty mutase (Sbm) operon not only transformed E. coli to be propionogenic (i.e., propionate-producing) but also introduced an intracellular “flux competition” between the traditional C2-fermentative pathway and the novel C3-fermentative pathway. Dissimilation of the major carbon source of glycerol was identified to critically affect such “flux competition” and, therefore, propionate synthesis. As a result, the propionogenic E. coli was further engineered by inactivation or overexpression of various genes involved in the glycerol dissimilation pathways and their individual genetic effects on propionate production were investigated. Generally, knocking out genes involved in glycerol dissimilation (except glpA) can minimize levels of solventogenesis and shift more dissimilated carbon flux toward the C3-fermentative pathway. For optimal propionate production with high C3:C2-fermentative product ratios, glycerol dissimilation should be channeled through the respiratory pathway and, upon suppressed solventogenesis with minimal production of highly reduced alcohols, the alternative NADH-consuming route associated with propionate synthesis can be critical for more flexible redox balancing. With the implementation of various biochemical and genetic strategies, high propionate titers of more than 11 g/L with high yields up to 0.4 g-propionate/g-glycerol (accounting for ~50 % of dissimilated glycerol) were achieved, demonstrating the potential for industrial application. To our knowledge, this represents the most effective engineered microbial system for propionate production with titers and yields comparable to those achieved by anaerobic batch cultivation of various native propionate-producing strains of Propionibacteria.
Starting Page	1057
Ending Page	1072
Page Count	16
File Format	PDF
ISSN	13675435
Journal	Journal of Industrial Microbiology and Biotechnology
Volume Number	42
Issue Number	7
e-ISSN	14765535
Language	English
Publisher	Springer Berlin Heidelberg
Publisher Date	2015-05-07
Publisher Place	Berlin, Heidelberg
Access Restriction	Subscribed
Subject Keyword	Escherichia coli Genetic engineering Glycerol Propionate Sleeping beauty mutase Microbiology Biochemistry Inorganic Chemistry Genetic Engineering Biotechnology Bioinformatics
Content Type	Text
Resource Type	Article
Subject	Medicine Bioengineering Applied Microbiology and Biotechnology Biotechnology

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