scholarly journals Production of itaconate by whole-cell bioconversion of citrate mediated by expression of multiple cis-aconitate decarboxylase (cadA) genes in Escherichia coli

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Junyoung Kim ◽  
Hyung-Min Seo ◽  
Shashi Kant Bhatia ◽  
Hun-Seok Song ◽  
Jung-Ho Kim ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Whole Cell ◽  
Whole Cell Bioconversion

scholarly journals High-Level Conversion of l-lysine into Cadaverine by Escherichia coli Whole Cell Biocatalyst Expressing Hafnia alvei l-lysine Decarboxylase

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1184 ◽  
Author(s):  
Kim ◽  
Baritugo ◽  
Oh ◽  
Kang ◽  
Jung ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Protein Expression ◽  
Pyridoxal Phosphate ◽  
Lysine Decarboxylase ◽  
Hafnia Alvei ◽  
Whole Cell ◽  
E Coli ◽  
Whole Cell Biocatalyst ◽  
High Level ◽  
Whole Cell Bioconversion

Cadaverine is a C5 diamine monomer used for the production of bio-based polyamide 510. Cadaverine is produced by the decarboxylation of l-lysine using a lysine decarboxylase (LDC). In this study, we developed recombinant Escherichia coli strains for the expression of LDC from Hafnia alvei. The resulting recombinant XBHaLDC strain was used as a whole cell biocatalyst for the high-level bioconversion of l-lysine into cadaverine without the supplementation of isopropyl β-d-1-thiogalactopyranoside (IPTG) for the induction of protein expression and pyridoxal phosphate (PLP), a key cofactor for an LDC reaction. The comparison of results from enzyme characterization of E. coli and H. alvei LDC revealed that H. alvei LDC exhibited greater bioconversion ability than E. coli LDC due to higher levels of protein expression in all cellular fractions and a higher specific activity at 37 °C (1825 U/mg protein > 1003 U/mg protein). The recombinant XBHaLDC and XBEcLDC strains were constructed for the high-level production of cadaverine. Recombinant XBHaLDC produced a 1.3-fold higher titer of cadaverine (6.1 g/L) than the XBEcLDC strain (4.8 g/L) from 10 g/L of l-lysine. Furthermore, XBHaLDC, concentrated to an optical density (OD600) of 50, efficiently produced 136 g/L of cadaverine from 200 g/L of l-lysine (97% molar yield) via an IPTG- and PLP-free whole cell bioconversion reaction. Cadaverine synthesized via a whole cell biocatalyst reaction using XBHaLDC was purified to polymer grade, and purified cadaverine was successfully used for the synthesis of polyamide 510. In conclusion, an IPTG- and PLP-free whole cell bioconversion process of l-lysine into cadaverine, using recombinant XBHaLDC, was successfully utilized for the production of bio-based polyamide 510, which has physical and thermal properties similar to polyamide 510 synthesized from chemical-grade cadaverine.

scholarly journals Ultrasound-assisted d-tartaric acid whole-cell bioconversion by recombinant Escherichia coli

2018 ◽  
Vol 42 ◽  
pp. 11-17 ◽  
Author(s):  
Weiliang Dong ◽  
Fenglian Zhao ◽  
Fengxue Xin ◽  
Aiyong He ◽  
Yue Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Tartaric Acid ◽  
Recombinant Escherichia Coli ◽  
Whole Cell ◽  
Ultrasound Assisted ◽  
Whole Cell Bioconversion

scholarly journals Ultrasound-assisted l-cysteine whole-cell bioconversion by recombinant Escherichia coli with tryptophan synthase

2021 ◽  
Vol 10 (1) ◽  
pp. 842-850
Author(s):  
Lisheng Xu ◽  
Furu Wu ◽  
Tingting Li ◽  
Xingtao Zhang ◽  
Qiong Chen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell System ◽  
Tryptophan Synthase ◽  
Cysteine Biosynthesis ◽  
Optimal Conditions ◽  
Whole Cell ◽  
G Cells ◽  
Biological Transformation ◽  
Ultrasound Assisted ◽  
Whole Cell Bioconversion

Abstract l-Cysteine is widely used in food, medicine, and cosmetics. In this study, a recombinant Escherichia coli whole-cell system with tryptophan synthase was used to complete the biological transformation of l-serine to l-cysteine, and bioconversion of l-cysteine was investigated by tryptophan synthase. The biotransformation of l-cysteine was optimized by response surface methodology. The optimal conditions obtained are 0.13 mol·L−1 l-serine, 75 min, 130 W ultrasound operation, where the V max of tryptophan synthase is 25.27 ± 0.16 (mmol·h−1·(g-cells)−1). The V max of tryptophan synthase for the biosynthesis without ultrasound is 12.91 ± 0.34 (mmol·h−1·(g-cells)−1). Kinetic analysis of the recombinant Escherichia coli whole-cell system with tryptophan synthase also showed that under the ultrasound treatment, the K m values of l-cysteine biosynthesis increase from 1.342 ± 0.11 mM for the shaking biotransformation to 2.555 ± 0.13 mM for ultrasound operation. The yield of l-cysteine reached 91% after 75 min of treatment after 130 W ultrasound, which is 1.9-fold higher than no ultrasound.

scholarly journals Tuning a bi-enzymatic cascade reaction in Escherichia coli to facilitate NADPH regeneration for ε-caprolactone production

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jinghui Xiong ◽  
Hefeng Chen ◽  
Ran Liu ◽  
Hao Yu ◽  
Min Zhuo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Binding Sites ◽  
Regeneration System ◽  
Nadph Regeneration ◽  
Whole Cell ◽  
Cyclohexanone Monooxygenase ◽  
Ribosome Binding ◽  
Ribosome Binding Sites ◽  
Whole Cell Biocatalyst ◽  
Substrate Tolerance

Abstractε-Caprolactone is a monomer of poly(ε-caprolactone) which has been widely used in tissue engineering due to its biodegradability and biocompatibility. To meet the massive demand for this monomer, an efficient whole-cell biocatalytic approach was constructed to boost the ε-caprolactone production using cyclohexanol as substrate. Combining an alcohol dehydrogenase (ADH) with a cyclohexanone monooxygenase (CHMO) in Escherichia coli, a self-sufficient NADPH-cofactor regeneration system was obtained. Furthermore, some improved variants with the better substrate tolerance and higher catalytic ability to ε-caprolactone production were designed by regulating the ribosome binding sites. The best mutant strain exhibited an ε-caprolactone yield of 0.80 mol/mol using 60 mM cyclohexanol as substrate, while the starting strain only got a conversion of 0.38 mol/mol when 20 mM cyclohexanol was supplemented. The engineered whole-cell biocatalyst was used in four sequential batches to achieve a production of 126 mM ε-caprolactone with a high molar yield of 0.78 mol/mol.

scholarly journals A Mechanism-Based Whole-Cell Screening Assay to Identify Inhibitors of Protein Export in Escherichia coli by the Sec Pathway

2012 ◽  
Vol 17 (4) ◽  
pp. 535-541 ◽  
Author(s):  
Gregory J. Crowther ◽  
S. Arshiya Quadri ◽  
Benjamin J. Shannon-Alferes ◽  
Wesley C. Van Voorhis ◽  
Henry Rosen
Keyword(s):  
Escherichia Coli ◽  
High Throughput Screening ◽  
Drug Target ◽  
Rapid Identification ◽  
Protein Synthesis Inhibitors ◽  
Screening Assay ◽  
Whole Cell ◽  
Sec Pathway ◽  
Associated Proteins ◽  
Pass Through

More than 20% of bacterial proteins are noncytoplasmic, and most of these pass through the SecYEG channel en route to the periplasm, cell membrane, or surrounding environment. The Sec pathway, encompassing SecYEG and several associated proteins (SecA, SecB, YidC, SecDFYajC), is of interest as a potential drug target because it is distinct from targets of current drugs, is essential for bacterial growth, and exhibits dissimilarities in eukaryotes and bacteria that increase the likelihood of selectively inhibiting the microbial pathway. As a step toward validating the pathway as a drug target, we have adapted a mechanism-based whole-cell assay in a manner suitable for high-throughput screening (HTS). The assay uses an engineered strain of Escherichia coli that accumulates beta-galactosidase (β-gal) in its cytoplasm if translocation through SecYEG is blocked. The assay should facilitate rapid identification of compounds that specifically block the Sec pathway because widely, toxic compounds and nonspecific protein synthesis inhibitors prevent β-gal production and thus do not register as hits. Testing of current antibiotics confirmed that they do not generally act through the Sec pathway. A mini-screen of 800 compounds indicated the assay’s readiness for larger screening projects.

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