Efficient Biosynthesis of (<i>R</i>)‐ or (<i>S</i>)‐2‐Hydroxybutyrate from <scp>l</scp>‐Threonine through a Synthetic Biology Approach

Yao, Peiyuan; Cui, Yunfeng; Sheng, Yu; Du, Yuncheng; Feng, Jinhui; Wu, Qingping; Zhu, Dunming

doi:10.1002/adsc.201600468

Cited by 15 publications

(19 citation statements)

References 71 publications

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“…The global regulation factor arcA deletion has been used in E. coli to activate the TCA cycle and aerobic respiration [46,63]. The global regulation factor fadR deletion has been used to increase the acetyl-CoA supply by enhancing the fatty acid degradation [6].…”

Section: Discussionmentioning

confidence: 99%

Expression regulation of multiple key genes to improve l-threonine in Escherichia coli

Zhao

Yang

et al. 2020

Microb Cell Fact

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Background: Escherichia coli is an important strain for l-threonine production. Genetic switch is a ubiquitous regulatory tool for gene expression in prokaryotic cells. To sense and regulate intracellular or extracellular chemicals, bacteria evolve a variety of transcription factors. The key enzymes required for l-threonine biosynthesis in E. coli are encoded by the thr operon. The thr operon could coordinate expression of these genes when l-threonine is in short supply in the cell. Results: The thrL leader regulatory elements were applied to regulate the expression of genes iclR, arcA, cpxR, gadE, fadR and pykF, while the threonine-activating promoters P cysH , P cysJ and P cysD were applied to regulate the expression of gene aspC, resulting in the increase of l-threonine production in an l-threonine producing E. coli strain TWF001. Firstly, different parts of the regulator thrL were inserted in the iclR regulator region in TWF001, and the best resulting strain TWF063 produced 16.34 g l-threonine from 40 g glucose after 30 h cultivation. Secondly, the gene aspC following different threonine-activating promoters was inserted into the chromosome of TWF063, and the best resulting strain TWF066 produced 17.56 g l-threonine from 40 g glucose after 30 h cultivation. Thirdly, the effect of expression regulation of arcA, cpxR, gadE, pykF and fadR was individually investigated on l-threonine production in TWF001. Finally, using TWF066 as the starting strain, the expression of genes arcA, cpxR, gadE, pykF and fadR was regulated individually or in combination to obtain the best strain for l-threonine production. The resulting strain TWF083, in which the expression of seven genes (iclR, aspC, arcA, cpxR, gadE, pykF, fadR and aspC) was regulated, produced 18.76 g l-threonine from 30 g glucose, 26.50 g l-threonine from 40 g glucose, or 26.93 g l-threonine from 50 g glucose after 30 h cultivation. In 48 h fed-batch fermentation, TWF083 could produce 116.62 g/L l-threonine with a yield of 0.486 g/g glucose and productivity of 2.43 g/L/h. Conclusion: The genetic engineering through the expression regulation of key genes is a better strategy than simple deletion of these genes to improve l-threonine production in E. coli. This strategy has little effect on the intracellular metabolism in the early stage of the growth but could increase l-threonine biosynthesis in the late stage.

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Section: Discussionmentioning

confidence: 99%

Expression regulation of multiple key genes to improve l-threonine in Escherichia coli

Zhao

Yang

et al. 2020

Microb Cell Fact

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“…Therefore, the assembly of small amino acids and aldehydes to form numerous α-keto acids and α-hydroxy acids is highly desired and remains a significant challenge. Fortunately, artificially designed multienzyme cascades, which offer a alternative to related chemical methods and protein engineering 3 , 11 , 17 , 20 , provide a useful tool for overcoming some challenging reactions 21 – 26 , such as the oxy- and amino-functionalization of alkenes 21 , 24 , 27 , 28 .…”

Section: Introductionmentioning

confidence: 99%

Asymmetric assembly of high-value α-functionalized organic acids using a biocatalytic chiral-group-resetting process

Song

Wang

et al. 2018

Nat Commun

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The preparation of α-functionalized organic acids can be greatly simplified by adopting a protocol involving the catalytic assembly of achiral building blocks. However, the enzymatic assembly of small amino acids and aldehydes to form numerous α-functionalized organic acids is highly desired and remains a significant challenge. Herein, we report an artificially designed chiral-group-resetting biocatalytic process, which uses simple achiral glycine and aldehydes to synthesize stereodefined α-functionalized organic acids. This cascade biocatalysis comprises a basic module and three different extender modules and operates in a modular assembly manner. The engineered Escherichia coli catalysts, which contained different module(s), provide access to α-keto acids, α-hydroxy acids, and α-amino acids with excellent conversion and enantioselectivities. Therefore, this biocatalytic process provides an attractive strategy for the conversion of low-cost achiral starting materials to high-value α-functionalized organic acids.

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“…Zhu et al. recently developed a similar but in vivo cascade from l ‐threonine to ( R )‐ or ( S )‐2‐hydroxybutyrate (Scheme b) . Besides TD above, other key enzymes are an l ‐lactate dehydrogenase ( l ‐LDH) from Oryctolagus cuniculus , a d ‐LDH from Staphylococcus epidermidis , and FDH.…”

Section: Recent Development Of Whole‐cell Cascade Biotransformationsmentioning

confidence: 99%

“…To date, many types of non‐oxidoreduction and reduction could be efficiently catalyzed by the corresponding enzymes, such as lipases, hydrolases, transaminases, dehydrogenases, and reductases . In several efficient enzyme cascades above, the reactions involved are mainly carboligation, reduction, deamination, and hydrolysis. More challenging reaction is oxidation, in particularly, oxyfunctionalization .…”

Section: Challenges and Potential Improvement Of Whole‐cell Cascade Bmentioning

confidence: 99%

Whole‐Cell Cascade Biotransformations for One‐Pot Multistep Organic Synthesis

2018

ChemCatChem

107

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Performing one‐pot multi‐catalysis reactions is a revolutionary tool for multistep synthesis, representing a fast‐developing theme in catalysis field. To develop cascade reactions, enzymes are ideal catalysts due to their compatible reaction conditions. The implementation of enzyme cascades in recombinant microbial cells provides easily available self‐replicating catalysts for facile one‐pot biotransformations to produce a wide range of high‐value (chiral) chemicals. In this minireview, we summarize the recent development of whole‐cell cascade biotransformations according to the types of substrates, ranging from petrochemicals to biochemicals. Furthermore, we provide general instructions for the establishment of in vivo enzyme cascades, discuss the encountered problems and the corresponding solutions, and highlight the promising directions for future advance.

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Efficient Biosynthesis of (R)‐ or (S)‐2‐Hydroxybutyrate from l‐Threonine through a Synthetic Biology Approach

Cited by 15 publications

References 71 publications

Expression regulation of multiple key genes to improve l-threonine in Escherichia coli

Expression regulation of multiple key genes to improve l-threonine in Escherichia coli

Asymmetric assembly of high-value α-functionalized organic acids using a biocatalytic chiral-group-resetting process

Whole‐Cell Cascade Biotransformations for One‐Pot Multistep Organic Synthesis

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