Efficient Conversion of Acetate to 3-Hydroxypropionic Acid by Engineered Escherichia coli

Ji Lee,Hyun Lim,Sanghak Cha,Gyoo Jung,Geon Lee,Chae Kang

doi:10.3390/catal8110525

Ji Lee, Hyun Lim + Show 4 more

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https://doi.org/10.3390/catal8110525

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Abstract

Acetate, which is an abundant carbon source, is a potential feedstock for microbial processes that produce diverse value-added chemicals. In this study, we produced 3-hydroxypropionic acid (3-HP) from acetate with engineered Escherichia coli. For the efficient conversion of acetate to 3-HP, we initially introduced heterologous mcr (encoding malonyl-CoA reductase) from Chloroflexus aurantiacus. Then, the acetate assimilating pathway and glyoxylate shunt pathway were activated by overexpressing acs (encoding acetyl-CoA synthetase) and deleting iclR (encoding the glyoxylate shunt pathway repressor). Because a key precursor malonyl-CoA is also consumed for fatty acid synthesis, we decreased carbon flux to fatty acid synthesis by adding cerulenin. Subsequently, we found that inhibiting fatty acid synthesis dramatically improved 3-HP production (3.00 g/L of 3-HP from 8.98 g/L of acetate). The results indicated that acetate can be used as a promising carbon source for microbial processes and that 3-HP can be produced from acetate with a high yield (44.6% of the theoretical maximum yield).

Highlights

Microbial conversion is a highly promising process for the production of diverse value-added chemicals and as an alternative to petroleum-based processes [1,2]
We demonstrated the efficient conversion of acetate to 3-hydroxypropionic acid (3-HP) by engineering a representative microorganism, Escherichia coli
For 3-HP production, we introduced mcr from C. aurantiacus into the E. coli strain BL21(DE3)

Summary

Introduction

Microbial conversion is a highly promising process for the production of diverse value-added chemicals and as an alternative to petroleum-based processes [1,2] It can utilize a variety of sugars such as glucose, galactose, xylose and glycerol, which are plentiful in nature and readily available as industrial waste, as a feedstock [3,4,5]. The use of acetate may reduce the cost of feedstock and thereby facilitate the development of more economic processes In this regard, several recent studies attempted to engineer microorganisms and demonstrated the successful conversion of acetate into value-added chemicals such as itaconic acid, succinic acid and fatty acid [9,10,11]

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