scholarly journals Engineering Escherichia coli for highly efficient production of lacto-N-triose II from N-acetylglucosamine, the monomer of chitin

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Duoduo Hu ◽  
Hao Wu ◽  
Yingying Zhu ◽  
Wenli Zhang ◽  
Wanmeng Mu
Keyword(s):  
Feeding Strategy ◽  
Carbon Sources ◽  
Value Added ◽  
Lactose Hydrolysis ◽  
Cell Factory ◽  
Efficient Production ◽  
E Coli ◽  
Maximum Titer ◽  
Related Pathway ◽  
Value Added Products

Abstract Background Lacto-N-triose II (LNT II), an important backbone for the synthesis of different human milk oligosaccharides, such as lacto-N-neotetraose and lacto-N-tetraose, has recently received significant attention. The production of LNT II from renewable carbon sources has attracted worldwide attention from the perspective of sustainable development and green environmental protection. Results In this study, we first constructed an engineered E. coli cell factory for producing LNT II from N-acetylglucosamine (GlcNAc) feedstock, a monomer of chitin, by introducing heterologous β-1,3-acetylglucosaminyltransferase, resulting in a LNT II titer of 0.12 g L−1. Then, lacZ (lactose hydrolysis) and nanE (GlcNAc-6-P epimerization to ManNAc-6-P) were inactivated to further strengthen the synthesis of LNT II, and the titer of LNT II was increased to 0.41 g L−1. To increase the supply of UDP-GlcNAc, a precursor of LNT II, related pathway enzymes including GlcNAc-6-P deacetylase, glucosamine synthase, and UDP-N-acetylglucosamine pyrophosphorylase, were overexpressed in combination, optimized, and modulated. Finally, a maximum titer of 15.8 g L−1 of LNT II was obtained in a 3-L bioreactor with optimal enzyme expression levels and β-lactose and GlcNAc feeding strategy. Conclusions Metabolic engineering of E. coli is an effective strategy for LNT II production from GlcNAc feedstock. The titer of LNT II could be significantly increased by modulating the gene expression strength and blocking the bypass pathway, providing a new utilization for GlcNAc to produce high value-added products.

scholarly journals Metabolic engineering Escherichia coli for efficient production of icariside D2

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Xue Liu ◽  
Lingling Li ◽  
Jincong Liu ◽  
Jianjun Qiao ◽  
Guang-Rong Zhao
Keyword(s):  
Escherichia Coli ◽  
De Novo ◽  
Carbon Sources ◽  
Gene Expression Pattern ◽  
Fine Tuning ◽  
Cell Factory ◽  
Efficient Production ◽  
Uridine Diphosphate ◽  
Microbial Cell Factory ◽  
E Coli

Abstract Background Icariside D2 is a plant-derived natural glycoside with pharmacological activities of inhibiting angiotensin-converting enzyme and killing leukemia cancer cells. Production of icariside D2 by plant extraction and chemical synthesis is inefficient and environmentally unfriendly. Microbial cell factory offers an attractive route for economical production of icariside D2 from renewable and sustainable bioresources. Results We metabolically constructed the biosynthetic pathway of icariside D2 in engineered Escherichia coli. We screened the uridine diphosphate glycosyltransferases (UGTs) and obtained an active RrUGT3 that regio-specifically glycosylated tyrosol at phenolic position to exclusively synthesize icariside D2. We put heterologous genes in E. coli cell for the de novo biosynthesis of icariside D2. By fine-tuning promoter and copy number as well as balancing gene expression pattern to decrease metabolic burden, the BMD10 monoculture was constructed. Parallelly, for balancing pathway strength, we established the BMT23–BMD12 coculture by distributing the icariside D2 biosynthetic genes to two E. coli strains BMT23 and BMD12, responsible for biosynthesis of tyrosol from preferential xylose and icariside D2 from glucose, respectively. Under the optimal conditions in fed-batch shake-flask fermentation, the BMD10 monoculture produced 3.80 g/L of icariside D2 using glucose as sole carbon source, and the BMT23–BMD12 coculture produced 2.92 g/L of icariside D2 using glucose–xylose mixture. Conclusions We for the first time reported the engineered E. coli for the de novo efficient production of icariside D2 with gram titer. It would be potent and sustainable approach for microbial production of icariside D2 from renewable carbon sources. E. coli–E. coli coculture approach is not limited to glycoside production, but could also be applied to other bioproducts.

scholarly journals Overview of nanocellulose as additives in paper processing and paper products

2021 ◽  
Vol 10 (1) ◽  
pp. 264-281
Author(s):  
Ao Li ◽  
Dezhong Xu ◽  
Lu Luo ◽  
Yalan Zhou ◽  
Wen Yan ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Paper Industry ◽  
Value Added ◽  
Environmental Concerns ◽  
Efficient Production ◽  
Efficient Utilization ◽  
Paper Recycling ◽  
Rapid Economic Growth ◽  
Recycled Fibers ◽  
Value Added Products

Abstract The rapid economic growth and environmental concerns have led to high demands on paper and paper-based products in terms of variety, quantity, quality, and specialty. Enhancement and functionalization with additives are constantly required. Moving away from traditional petroleum-based additives, researchers have attempted to use “green” nanoadditives by introducing renewable environmentally friendly nanocellulose. This article studies the functions of nanocellulose as bio-additives (enhancer, retention and filtration reagent, and coating aid) in paper and paper products, and overviews the research development of nanocellulose-based additives and their applications in the paper industry for both efficient production and paper functionalization. The review shows that (1) a variety of nanocellulose-based bioadditives have been reported for various applications in paper and paper-based products, while commercially viable developments are to be advanced; (2) nanocellulose was mostly formulated with other polymer and particles as additives to achieve their synergistic effects; (3) major interests have concentrated on the nanocellulose in the specialty papers as representing more value added products and in the efficient utilization of recycled fibers, which remains most attractive and promising for future development. This report shall provide most useful database information for researchers and industries for paper recycling and enhancement, and paper-based products innovation and application.

scholarly journals Upcycling chitin-containing waste into organonitrogen chemicals via an integrated process

2020 ◽  
Vol 117 (14) ◽  
pp. 7719-7728 ◽  
Author(s):  
Xiaoqiang Ma ◽  
Gökalp Gözaydın ◽  
Huiying Yang ◽  
Wenbo Ning ◽  
Xi Han ◽  
...  
Keyword(s):  
Wide Spectrum ◽  
Value Added ◽  
Direct Conversion ◽  
Water Soluble ◽  
Integrated Biorefinery ◽  
E Coli ◽  
Shrimp Shell ◽  
Shell Waste ◽  
Shrimp Shell Waste ◽  
Value Added Products

Chitin is the most abundant renewable nitrogenous material on earth and is accessible to humans in the form of crustacean shell waste. Such waste has been severely underutilized, resulting in both resource wastage and disposal issues. Upcycling chitin-containing waste into value-added products is an attractive solution. However, the direct conversion of crustacean shell waste-derived chitin into a wide spectrum of nitrogen-containing chemicals (NCCs) is challenging via conventional catalytic processes. To address this challenge, in this study, we developed an integrated biorefinery process to upgrade shell waste-derived chitin into two aromatic NCCs that currently cannot be synthesized from chitin via any chemical process (tyrosine andl-DOPA). The process involves a pretreatment of chitin-containing shell waste and an enzymatic/fermentative bioprocess using metabolically engineeredEscherichia coli. The pretreatment step achieved an almost 100% recovery and partial depolymerization of chitin from shrimp shell waste (SSW), thereby offering water-soluble chitin hydrolysates for the downstream microbial process under mild conditions. The engineeredE. colistrains produced 0.91 g/L tyrosine or 0.41 g/Ll-DOPA from 22.5 g/L unpurified SSW-derived chitin hydrolysates, demonstrating the feasibility of upcycling renewable chitin-containing waste into value-added NCCs via this integrated biorefinery, which bypassed the Haber–Bosch process in providing a nitrogen source.

scholarly journals Microbial Upgrading of Acetate into Value-Added Products—Examining Microbial Diversity, Bioenergetic Constraints and Metabolic Engineering Approaches

2020 ◽  
Vol 21 (22) ◽  
pp. 8777
Author(s):  
Regina Kutscha ◽  
Stefan Pflügl
Keyword(s):  
Metabolic Engineering ◽  
Energy Content ◽  
Value Added ◽  
Inhibitory Effect ◽  
Low Energy ◽  
Waste Streams ◽  
E Coli ◽  
Increasing Trend ◽  
Engineering Measures ◽  
Value Added Products

Ecological concerns have recently led to the increasing trend to upgrade carbon contained in waste streams into valuable chemicals. One of these components is acetate. Its microbial upgrading is possible in various species, with Escherichia coli being the best-studied. Several chemicals derived from acetate have already been successfully produced in E. coli on a laboratory scale, including acetone, itaconic acid, mevalonate, and tyrosine. As acetate is a carbon source with a low energy content compared to glucose or glycerol, energy- and redox-balancing plays an important role in acetate-based growth and production. In addition to the energetic challenges, acetate has an inhibitory effect on microorganisms, reducing growth rates, and limiting product concentrations. Moreover, extensive metabolic engineering is necessary to obtain a broad range of acetate-based products. In this review, we illustrate some of the necessary energetic considerations to establish robust production processes by presenting calculations of maximum theoretical product and carbon yields. Moreover, different strategies to deal with energetic and metabolic challenges are presented. Finally, we summarize ways to alleviate acetate toxicity and give an overview of process engineering measures that enable sustainable acetate-based production of value-added chemicals.

scholarly journals De novo biosynthesis of paracetamol from glucose by metabolically engineered Escherichia coli

2021 ◽  
Author(s):  
Daoyi Guo ◽  
Xiao Fu ◽  
Sijia Kong ◽  
Yue Sun ◽  
Hong Pan
Keyword(s):  
Candida Parapsilosis ◽  
De Novo ◽  
Raw Materials ◽  
Carbon Sources ◽  
Cell Factory ◽  
Aminobenzoic Acid ◽  
Renewable Raw Materials ◽  
E Coli ◽  
Renewable Sugars ◽  
First Time

Abstract Background: Paracetamol is among the most commonly used of all medications, widely accepted as a safe and effective analgesic/antipyretic for mild-to-moderate pain and fever. The biosynthesis of paracetamol from renewable sugars has not been reported so far, due to the lack of natural biosynthetic pathways. Results: In this study, we demonstrated for the first time the development of an E. coli cell factory for production of paracetamol from glucose. First, p-aminobenzoic acid, an intermediate of folic acid in microorganism, is selected as precursor substrates for the production of paracetamol. Second, a monooxygenase MNX1 from Candida parapsilosis CBS604 that can efficiently catalyze the decarboxylation and hydroxylation of p-aminobenzoic acid into corresponding p-aminophenol and another N-acetyltransferase PANAT from Pseudomonas aeruginosa that can efficiently catalyze the esterification of acetyl-CoA and p-aminophenol to form paracetamol were discovered. Finally, an engineered E. coli that allows production of paracetamol from simple carbon sources was established. Conclusions: The present study opens up a new direction for engineering microbial production of paracetamol from cheap and readily-available renewable raw materials such as sugars and cellulose in the future.

scholarly journals Efficient production of myo-inositol in Escherichia coli through metabolic engineering

2020 ◽  
Author(s):  
Ran You ◽  
Lei Wang ◽  
Congrong Shi ◽  
Hao Chen ◽  
Shasha Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Metabolic Engineering ◽  
Carbon Flux ◽  
Value Added ◽  
Efficient Production ◽  
Wild Type ◽  
Food Industries ◽  
E Coli ◽  
Mixed Carbon Source

Abstract Background: The biosynthesis of high value-added compounds using metabolically engineered strains has received wide attention in recent years. Myo-inositol (inositol), an important compound in the pharmaceutics, cosmetics and food industries, is usually produced from phytate via a harsh set of chemical reactions. Recombinant Escherichia coli strains have been constructed by metabolic engineering strategies to produce inositol, but with a low yield. The proper distribution of carbon flux between cell growth and inositol production is a major challenge for constructing an efficient inositol-synthesis pathway in bacteria. Construction of metabolically engineered E. coli strains with high stoichiometric yield of inositol is desirable.Results: In the present study, we designed an inositol-synthesis pathway from glucose with a theoretical stoichiometric yield of 1 mol inositol/mol glucose. Recombinant E. coli strains with high stoichiometric yield (>0.7 mol inositol/mol glucose) were obtained. Inositol was successfully biosynthesized after introducing two crucial enzymes: inositol-3-phosphate synthase (IPS) from Trypanosoma brucei, and inositol monophosphatase (IMP) from E. coli. Based on starting strains E. coli BW25113 (wild-type) and SG104 (ΔptsG::glk, ΔgalR::zglf, ΔpoxB::acs), a series of engineered strains for inositol production was constructed by deleting the key genes pgi, pfkA and pykF. Plasmid-based expression systems for IPS and IMP were optimized, and expression of the gene zwf was regulated to enhance the stoichiometric yield of inositol. The highest stoichiometric yield (0.96 mol inositol/mol glucose) was achieved from recombinant strain R15 (SG104, Δpgi, Δpgm, and RBSL5-zwf). Strain R04 (SG104 and Δpgi) reached high-density in a 1-L fermenter when using glucose and glycerol as a mixed carbon source. In scaled-up fed-batch bioconversion in situ using strain R04, 0.82 mol inositol/mol glucose was produced within 23 h, corresponding to a titer of 106.3 g/L (590.5 mM) inositol.Conclusions: The biosynthesis of inositol from glucose in recombinant E. coli was optimized by metabolic engineering strategies. The metabolically engineered E. coli strains represent a promising method for future inositol production. This study provides an essential reference to obtain a suitable distribution of carbon flux between glycolysis and inositol synthesis.

scholarly journals α-Farnesene production from lipid by engineered Yarrowia lipolytica

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yinghang Liu ◽  
Zhaoxuan Wang ◽  
Zhiyong Cui ◽  
Qingsheng Qi ◽  
Jin Hou
Keyword(s):  
Oleic Acid ◽  
Yarrowia Lipolytica ◽  
Edible Oils ◽  
Economic Value ◽  
Value Added ◽  
Waste Cooking Oil ◽  
Limiting Factor ◽  
Cell Factory ◽  
Microbial Cell Factory ◽  
Value Added Products

AbstractProducing high value-added products from waste lipid feedstock by microbial cell factory has great advantages to minimize the pollution as well as improve the economic value of wasted oils and fats. Yarrowia lipolytica is a non-conventional oleaginous yeast and can grow on a variety of hydrophobic substrates. In this study, we explored its ability to synthesize α-farnesene, an important sesquiterpene, using lipid feedstock. Based on the α-farnesene production strain, we constructed previously, we identified that Erg12 was the key limiting factor to further increase the α-farnesene production. The α-farnesene production was improved by 35.8% through increasing the copy number of ERG12 and FSERG20 on oleic acid substrate. Expression of heterologous VHb further improved α-farnesene production by 12.7%. Combining metabolic engineering with the optimization of fermentation conditions, the α-farnesene titer and yield reached 10.2 g/L and 0.1 g/g oleic acid, respectively, in fed-batch cultivation. The α-farnesene synthesis ability on waste cooking oil and other edible oils were also explored. Compared with using glucose as carbon source, using lipid substrates obtained higher α-farnesene yield and titer, but lower by-products accumulation, demonstrating the advantage of Y. lipolytica to synthesize high value-added products using lipid feedstock.

scholarly journals Efficient production of myo-inositol in Escherichia coli through metabolic engineering

2020 ◽  
Author(s):  
Ran You ◽  
Lei Wang ◽  
Congrong Shi ◽  
Hao Chen ◽  
Shasha Zhang ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
Carbon Flux ◽  
Scale Up ◽  
Value Added ◽  
Efficient Production ◽  
Synthetic Pathway ◽  
E Coli ◽  
Mixed Carbon Source ◽  
Glycolysis Pathway

Abstract Background The biosynthesis of high value-added compounds through metabolically engineered strains has received widely attention in recent years. As an effective compound in pharmaceutical, cosmetic and food industry, myo-inositol (inositol) is mainly produced via a harsh set of chemical reactions from phytate. The proper distribution of carbon flux between cell growth and inositol production was a major challenge for constructing an efficient inositol-synthetic pathway. Recombinant E. coli strains have been constructed by metabolic engineering strategies to produce inositol, yet with a low yield. Therefore, construction of E. coli metabolically engineered strains with high stoichiometric yield will be attractive. Results In the present study, the recombinant E. coli strains with high stoichiometric yield (> 0.7 mol inositol/mol glucose) were obtained to efficiently synthesize inositol. Inositol was successfully biosynthesized after introducing two crucial enzymes, inositol-3-phosphate synthase (IPS) from Trypanosoma brucei , and inositol monophosphatase (IMP) from E. coli. Based on starting strains E. coli BW25113 (wild type) and SG104 ( ΔptsG::glk , ΔgalR::zglf , ΔpoxB::acs ), a series of engineered strains for inositol production were constructed by deleting the key genes pgi, pfkA or pykF . Furthermore, the plasmid expression systems of IPS and IMP were optimized, and the gene zwf was regulated to enhance stoichiometric yield. The highest stoichiometric yield (0.96 mol inositol/mol glucose) was achieved with the combined strain R15 of SG104, Δpgi , Δpgm , and RBSL5-zwf. Simultaneously, the engineered strain R04 reached high-density fermentation level in a 1-L fermenter by using glucose and glycerol as mixed carbon source. In the scale-up bioconversion in situ with R04, 0.82 mol inositol/mol glucose was produced by fed-batch within 23 h, corresponding to a titer of 106.3 g/L (590.5 mM). Conclusions The biosynthetic pathway of inositol from glucose in recombinant E. coli was optimized by metabolic engineering strategies. The metabolically engineered E. coli strains represent a promising method for future inositol production. This study provided an essential reference to obtain a suitable distribution of carbon flux between glycolysis pathway and product synthetic pathway.

scholarly journals Synthetic biology toolkit for engineering Cupriviadus necator H16 as a platform for CO2 valorization

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Haojie Pan ◽  
Jia Wang ◽  
Haoliang Wu ◽  
Zhongjian Li ◽  
Jiazhang Lian
Keyword(s):  
Synthetic Biology ◽  
Genetic Engineering ◽  
Genome Engineering ◽  
Ralstonia Eutropha ◽  
Heterologous Gene Expression ◽  
Value Added ◽  
Cell Factory ◽  
Main Body ◽  
Cell Factories ◽  
Value Added Products

Abstract Background CO2 valorization is one of the effective methods to solve current environmental and energy problems, in which microbial electrosynthesis (MES) system has proved feasible and efficient. Cupriviadus necator (Ralstonia eutropha) H16, a model chemolithoautotroph, is a microbe of choice for CO2 conversion, especially with the ability to be employed in MES due to the presence of genes encoding [NiFe]-hydrogenases and all the Calvin–Benson–Basham cycle enzymes. The CO2 valorization strategy will make sense because the required hydrogen can be produced from renewable electricity independently of fossil fuels. Main body In this review, synthetic biology toolkit for C. necator H16, including genetic engineering vectors, heterologous gene expression elements, platform strain and genome engineering, and transformation strategies, is firstly summarized. Then, the review discusses how to apply these tools to make C. necator H16 an efficient cell factory for converting CO2 to value-added products, with the examples of alcohols, fatty acids, and terpenoids. The review is concluded with the limitation of current genetic tools and perspectives on the development of more efficient and convenient methods as well as the extensive applications of C. necator H16. Conclusions Great progress has been made on genetic engineering toolkit and synthetic biology applications of C. necator H16. Nevertheless, more efforts are expected in the near future to engineer C. necator H16 as efficient cell factories for the conversion of CO2 to value-added products.

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