scholarly journals Modulating the Precursor and Terpene Synthase Supply for the Whole-Cell Biocatalytic Production of the Sesquiterpene (+)-Zizaene in a Pathway Engineered E. coli

Genes ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 478 ◽  
Author(s):  
Francisco Aguilar ◽  
Thomas Scheper ◽  
Sascha Beutel

The vetiver essential oil from Chrysopogon zizanioides contains fragrant sesquiterpenes used widely in the formulation of nearly 20% of men’s cosmetics. The growing demand and issues in the supply have raised interest in the microbial production of the sesquiterpene khusimol, the main compound of the vetiver essential oil due to its woody smell. In this study, we engineered the biosynthetic pathway for the production of (+)-zizaene, the immediate precursor of khusimol. A systematic approach of metabolic engineering in Escherichia coli was applied to modulate the critical bottlenecks of the metabolic flux towards (+)-zizaene. Initially, production of (+)-zizaene was possible with the endogenous methylerythritol phosphate pathway and the codon-optimized zizaene synthase (ZS). Raising the precursor E,E-farnesyl diphosphate supply through the mevalonate pathway improved the (+)-zizaene titers 2.7-fold, although a limitation of the ZS supply was observed. To increase the ZS supply, distinct promoters were tested for the expression of the ZS gene, which augmented 7.2-fold in the (+)-zizaene titers. Final metabolic enhancement for the ZS supply by using a multi-plasmid strain harboring multiple copies of the ZS gene improved the (+)-zizaene titers 1.3-fold. The optimization of the fermentation conditions increased the (+)-zizaene titers 2.2-fold, achieving the highest (+)-zizaene titer of 25.09 mg L−1. This study provides an alternative strategy to enhance the terpene synthase supply for the engineering of isoprenoids. Moreover, it demonstrates the development of a novel microbial platform for the sustainable production of fragrant molecules for the cosmetic industry.

2003 ◽  
Vol 75 (2-3) ◽  
pp. 375-388 ◽  
Author(s):  
M. Rohmer

A long-overlooked metabolic pathway for isoprenoid biosynthesis, the mevalonate-independent methylerythritol phosphate (MEP) pathway, is present in many bacteria and in the chloroplasts of all phototrophic organisms. It represents an alternative to the well known mevalonate pathway, which is present in animals, fungi, plant cytoplasm, archaebacteria, and some eubacteria. This contribution summarizes key steps of its elucidation and the state-of-the-art knowledge of this biosynthetic pathway, which represents a novel target for antibacterial and antiparasitic drugs.


2019 ◽  
Vol 20 (7) ◽  
pp. 1669 ◽  
Author(s):  
Hui Wei ◽  
Ali Movahedi ◽  
Chen Xu ◽  
Weibo Sun ◽  
Amir Almasi Zadeh Yaghuti ◽  
...  

1-Deoxy-d-xylulose-5-phosphate synthase (DXS) is the rate-limiting enzyme in the plastidial methylerythritol phosphate pathway (MEP). In this study, PtDXS (XM_024607716.1) was isolated from Populus trichocarpa. A bioinformatics analysis revealed that PtDXS had high homology with the DXSs of other plant species. PtDXS expression differed among plant tissues and was highest in young leaves and lowest in roots. The recombinant protein was produced in Escherichia coli BL21 (DE3), purified, and its activity evaluated. The purified protein was capable of catalyzing the formation of 1-deoxy-d-xylulose-5-phosphate (DXP) from glyceraldehyde-3-phosphate and pyruvate. A functional color assay in E. coli harboring pAC-BETA indicated that PtDXS encodes a functional protein involved in the biosynthesis of isoprenoid precursors. The treatment of P. trichocarpa seedlings with 200 μM abscisic acid (ABA), 200 mM NaCl, 10% polyethylene glycol6000, and 2 mM H2O2 resulted in increased expression of PtDXS. The ABA and gibberellic acid contents of the transgenic lines (Poplar Nanlin 895) were higher than wild types, suggesting that DXS is important in terpenoid biosynthesis. Overexpression of PtDXS enhanced resistance to S. populiperda infection. Furthermore, the transgenic lines showed decreased feeding by Micromelalopha troglodyta, supporting the notion that PtDXS is a key enzyme in terpenoid biosynthesis.


2001 ◽  
Vol 183 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Frederick M. Hahn ◽  
Lisa M. Eubanks ◽  
Charles A. Testa ◽  
Brian S. J. Blagg ◽  
Jonathan A. Baker ◽  
...  

ABSTRACT In eubacteria, green algae, and plant chloroplasts, isopentenyl diphosphate, a key intermediate in the biosynthesis of isoprenoids, is synthesized by the methylerythritol phosphate pathway. The five carbons of the basic isoprenoid unit are assembled by joining pyruvate and d-glyceraldehyde 3-phosphate. The reaction is catalyzed by the thiamine diphosphate-dependent enzyme 1-deoxy-d-xylulose 5-phosphate synthase. InRhodobacter capsulatus, two open reading frames (ORFs) carry the genes that encode 1-deoxy-d-xylulose 5-phosphate synthase. ORF 2816 is located in the photosynthesis-related gene cluster, along with most of the genes required for synthesis of the photosynthetic machinery of the bacterium, whereas ORF 2895 is located elsewhere in the genome. The proteins encoded by ORF 2816 and ORF 2895, 1-deoxy-d-xylulose 5-phosphate synthase A and B, containing a His6 tag, were synthesized in Escherichia coli and purified to greater than 95% homogeneity in two steps. 1-Deoxy-d-xylulose 5-phosphate synthase A appears to be a homodimer with 68 kDa subunits. A new assay was developed, and the following steady-state kinetic constants were determined for 1-deoxy-d-xylulose 5-phosphate synthase A and B: Km pyruvate = 0.61 and 3.0 mM, Km d-glyceraldehyde 3-phosphate = 150 and 120 μM, andV max = 1.9 and 1.4 μmol/min/mg in 200 mM sodium citrate (pH 7.4). The ORF encoding 1-deoxy-d-xylulose 5-phosphate synthase B complemented the disrupted essential dxs gene in E. coli strain FH11.


2017 ◽  
Vol 30 (2) ◽  
pp. 27-35 ◽  
Author(s):  
Shayma T. G. Al-Sahlany

Soy protein with essential oil of lemon peel was used to produce a biodegradable film, which showed inhibition activity against some species of selected bacterial strains. The films were white cheese coating and studied for its biodegradation in the soil. The percentage of soy protein extract was 15% (W: W) while the percentage of lemon peel essential oil was 3% (V: W). The GC-MS result of lemon peel essential oil consisted of 38 compounds, of which the main compound is D-Limonene in 63.43%. The films produced showed inhibition activity against both Gram-positive and Gramnegative bacteria. Inhibition activity was highest against Staphylococcus aureus (22 mm zone), while E. coli O157: H7 had the lowest inhibition (18mm) when 0.1mL of essential oil with 10mL film mixed. The coating process of white cheese reduced the total microbial population (CFU/g) during 30 days of storage time. The TCB, TC, ST and MY of cheese coating were 4.28, 1.53, 1.62 and 1.33 log. CFU/g respectively after 30 days compared to the cheese non-coating samples, with 6.53, 2.51, 3.17 and 1.81 log. CFU/g, respectively. The biodegradation in soil was 97 and 72% for soy protein film and soy protein film with lemon peel essential oil after 35 days.


2020 ◽  
Vol 10 (3) ◽  
pp. 272-278
Author(s):  
Ardalan Pasdaran ◽  
Satyajit D. Sarker ◽  
Lutfun Nahar ◽  
Azadeh Hamedi

Background: The essential oil from the Acantholimon genus have been an integral part of the traditional food additive in Middle East. Most of the plants in Acantholimon genus have not been studied scientifically. The aim of this study is to investigate the chemical composition, antibacterial, insecticidal and anti-oxidant activities of three Acantholimon species including Acantholimon atropatanum, A. gilliatii and A. tragacanthium. Method: The essential oils of the aerial parts were extracted by hydrodistillation. Chemical constitutions were identified by gas chromatography- mass spectroscopy technique, also their toxicities were assessed against the two important grain products pests, Oryzeaphilus mercator and Tribolium castaneum. Antibacterial activity was assessed against the three foodborne bacteria that include Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus based on the disc diffusion assay. Free-radical-scavenging property was identified based on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. Results: 2-hexahydrofarnesyl acetone was the main compound in A. gilliatii and A. tragacanthium, whilst farnesyl acetone, heptacosane and germacrene D were the principal components of A. atropatanum essential oil. These oils exhibited 40-90% mortality of O. mercator and/or T. castaneum at a dose of 12 μl/l air after 48h of exposure, and exhibited significant free-radicalscavenging property (RC50 = 3.7 × 10-3 - 8.3 × 10-3 mg/ml). The oils of A. tragacanthium and A. gilliatii showed a weaker antibacterial activity compared to A. atropatanum. Conclusion: A. atropatanum, A. gilliatii and A. tragacanthium essential oils had significant insecticidal and anti-oxidant properties. They also showed week to moderate antibacterial activity against P. aeruginosa and S. aureus.


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