scholarly journals Synergetic Fermentation of Glucose and Glycerol for High-Yield N-Acetylglucosamine Production in Escherichia coli

2022 ◽  
Vol 23 (2) ◽  
pp. 773
Author(s):  
Kaikai Wang ◽  
Xiaolu Wang ◽  
Huiying Luo ◽  
Yaru Wang ◽  
Yuan Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Carbon Flux ◽  
Glucose Consumption ◽  
Amino Sugar ◽  
Fermentation Medium ◽  
High Yield ◽  
Final Strain ◽  
Pharmaceutical Industries ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Utilization Strategy

N-acetylglucosamine (GlcNAc) is an amino sugar that has been widely used in the nutraceutical and pharmaceutical industries. Recently, microbial production of GlcNAc has been developed. One major challenge for efficient biosynthesis of GlcNAc is to achieve appropriate carbon flux distribution between growth and production. Here, a synergistic substrate co-utilization strategy was used to address this challenge. Specifically, glycerol was utilized to support cell growth and generate glutamine and acetyl-CoA, which are amino and acetyl donors, respectively, for GlcNAc biosynthesis, while glucose was retained for GlcNAc production. Thanks to deletion of the 6-phosphofructokinase (PfkA and PfkB) and glucose-6-phosphate dehydrogenase (ZWF) genes, the main glucose catabolism pathways of Escherichia coli were blocked. The resultant mutant showed a severe defect in glucose consumption. Then, the GlcNAc production module containing glucosamine-6-phosphate synthase (GlmS*), glucosamine-6-phosphate N-acetyltransferase (GNA1*) and GlcNAc-6-phosphate phosphatase (YqaB) expression cassettes was introduced into the mutant, to drive the carbon flux from glucose to GlcNAc. Furthermore, co-utilization of glucose and glycerol was achieved by overexpression of glycerol kinase (GlpK) gene. Using the optimized fermentation medium, the final strain produced GlcNAc with a high stoichiometric yield of 0.64 mol/mol glucose. This study offers a promising strategy to address the challenge of distributing carbon flux in GlcNAc production.

scholarly journals Rational Metabolic Engineering of Escherichia Coli for High-yield L-serine Production

2020 ◽  
Author(s):  
Chenyang Wang ◽  
Junjun Wu ◽  
Lei Wang ◽  
Xiaojia Chen ◽  
Qinyu Li ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Large Scale ◽  
Regulatory Mechanism ◽  
Feedback Inhibition ◽  
Random Mutagenesis ◽  
Phosphoglycerate Kinase ◽  
High Yield ◽  
High Productivity ◽  
Yield Production ◽  
Pharmaceutical Industries

Abstract Background: L-serine is widely used in the food, cosmetic and pharmaceutical industries, and direct fermentation of L-serine from glucose is an attractive technique. However, L-serine producers have historically been developed via classical random mutagenesis due to the complicated metabolic network and regulatory mechanism of L-serine production, leading to un-optimal productivity and yield of L-serine and thus limiting its large-scale industrial production. Result: In this study, a high-yield and high-productivity Escherichia coli strain was constructed by a defined genetic modification methodology for L-serine production. First, L-serine-mediated feedback inhibition was removed and L-serine biosynthetic pathway genes (serAfr, serC and serB) associated with phosphoglycerate kinase (pgk) were overexpressed. Secondly, L-serine conversion pathway was further examined by introducing a glyA mutation (K229G) and deleting other degrading enzymes based on deletion of initial sdaA. Finally, the L-serine transport system was rationally engineered to reduce the uptake and accelerate the export of L-serine. The optimally engineered strain produced 35 g/L L-serine with a productivity of 0.98 g/L/h and yield of 0.42 g/g glucose in a 5-L fermenter, the highest productivity and yield of L-serine from glucose reported to date. Transcriptome and intermediate metabolite were analyzed to further understand the regulatory mechanism of L-serine production. Conclusion: These results demonstrated that combined metabolic and bioprocess engineering strategies can improve L-serine productivity and yield, thus providing basic principles for rationally designing of high-yield production strains and paving the way for towards a simple and economical process for industrial L-serine production.

scholarly journals Improved Yield of Recombinant Protein via Flagella Regulator Deletion in Escherichia coli

2021 ◽  
Vol 12 ◽  
Author(s):  
Jae-Ho Han ◽  
Sang Taek Jung ◽  
Min-Kyu Oh
Keyword(s):  
Escherichia Coli ◽  
Recombinant Protein ◽  
Protein Production ◽  
Metabolic Flux ◽  
Tricarboxylic Acid Cycle ◽  
Glucose Consumption ◽  
High Yield ◽  
Carbon Substrate ◽  
Flux Analysis ◽  
Flagella Assembly

Protein production requires a significant amount of intracellular energy. Eliminating the flagella has been proposed to help Escherichia coli improve protein production by reducing energy consumption. In this study, the gene encoding a subunit of FlhC, a master regulator of flagella assembly, was deleted to reduce the expression of flagella-related genes. FlhC knockout in the ptsG-deleted strain triggered significant growth retardation with increased ATP levels and a higher NADPH/NADP+ ratio. Metabolic flux analysis using a 13C-labeled carbon substrate showed increased fluxes toward the pentose phosphate and tricarboxylic acid cycle pathways in the flhC- and ptsG-deleted strains. Introduction of a high copy number plasmid or overexpression of the recombinant protein in this strain restored growth rate without increasing glucose consumption. These results suggest that the metabolic burden caused by flhC deletion was resolved by recombinant protein production. The recombinant enhanced green fluorescent protein yield per glucose consumption increased 1.81-fold in the flhC mutant strain. Thus, our study demonstrates that high-yield production of the recombinant protein was achieved with reduced flagella formation.

scholarly journals TP53-Induced Glycolysis and Apoptosis Regulator (TIGAR) Is Upregulated in Lymphocytes Stimulated with Concanavalin A

2021 ◽  
Vol 22 (14) ◽  
pp. 7436
Author(s):  
Helga Simon-Molas ◽  
Xavier Vallvé-Martínez ◽  
Irene Caldera-Quevedo ◽  
Pere Fontova ◽  
Claudia Arnedo-Pac ◽  
...  
Keyword(s):  
Concanavalin A ◽  
Carbon Flux ◽  
Human Lymphocytes ◽  
Tumor Development ◽  
Pentose Phosphate ◽  
Akt Signaling Pathway ◽  
G6pdh Activity ◽  
Physiological Conditions ◽  
Glucose 6 Phosphate Dehydrogenase

The glycolytic modulator TP53-Inducible Glycolysis and Apoptosis Regulator (TIGAR) is overexpressed in several types of cancer and has a role in metabolic rewiring during tumor development. However, little is known about the role of this enzyme in proliferative tissues under physiological conditions. In the current work, we analysed the role of TIGAR in primary human lymphocytes stimulated with the mitotic agent Concanavalin A (ConA). We found that TIGAR expression was induced in stimulated lymphocytes through the PI3K/AKT pathway, since Akti-1/2 and LY294002 inhibitors prevented the upregulation of TIGAR in response to ConA. In addition, suppression of TIGAR expression by siRNA decreased the levels of the proliferative marker PCNA and increased cellular ROS levels. In this model, TIGAR was found to support the activity of glucose 6-phosphate dehydrogenase (G6PDH), the first enzyme of the pentose phosphate pathway (PPP), since the inhibition of TIGAR reduced G6PDH activity and increased autophagy. In conclusion, we demonstrate here that TIGAR is upregulated in stimulated human lymphocytes through the PI3K/AKT signaling pathway, which contributes to the redirection of the carbon flux to the PPP.

scholarly journals 1671. Diagnosis and management of Escherichia coli bacteriuria at a Veterans Affairs hospital

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S821-S821
Author(s):  
Niyati H Shah ◽  
Brooke K Decker ◽  
Brooke K Decker ◽  
Gaetan Sgro ◽  
Monique Y Boudreaux-Kelly ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Treatment ◽  
High Yield ◽  
Comorbid Conditions ◽  
Provider Education ◽  
Transmitted Infection ◽  
Physician Practices ◽  
E Coli ◽  
Diagnosis And Management ◽  
Tract Infections

Abstract Background The IDSA recommends against screening for and treating ASB in all patients except for those pregnant or undergoing urologic procedures. Nevertheless, antibiotic treatment of ASB is widespread. We conducted a retrospective analysis of physician practices in diagnosis and management of Escherichia coli (E. coli) ASB in a male Veteran population, and compared outcomes in ASB patients treated or not treated with antibiotics. Methods Patients with an E. coli positive urine culture during an ED visit or inpatient admission from 01/2017 to 12/2017 were screened. Patients admitted to the intensive care unit or diagnosed with a sexually transmitted infection, pyelonephritis, prostatitis, or epididymitis/orchitis were excluded. A total of 163 patients were included. Demographics, clinical comorbidities and severity of illness, and outcomes were compared in ASB patients managed with or without antibiotics. ANOVA and Chi-square or Fisher’s exact tests were utilized for comparing measurements. Results ASB was present in 92/163 patients. The majority (74%) of these patients were given antibiotics. Regardless of qSOFA score or alternate infection, there were no significant differences in outcomes between ASB patients treated or not treated with antibiotics: 3-month mortality (15% vs 21%; p = 0.53), emergence of newly resistant bacterial pathogens (7% vs 13%; p = 0.43), recurrent urinary tract infections (61% vs 50%; p = 0.72), clearance of urinary pathogens (75% vs 58%; p = 0.45), length of hospital stay (7 vs 6 days, p = 0.67). Factors that were predictive of physician treatment of ASB included patient comorbid conditions such as benign prostatic hyperplasia, pyuria, and the absence of hematuria. The incidence of adverse events with antibiotic treatment of ASB was low. Conclusion The rate of antibiotic treatment of E. coli ASB in male veterans is high. Outcomes do not differ among ASB patients managed with or without antibiotics. Future studies examining outcomes in patients prescribed antibiotics for multiple episodes of ASB may yield differences, particularly in emergence of resistant pathogens. Focusing on patients with comorbid conditions who are not critically ill would be a high yield target for provider education to reduce ASB treatment. Disclosures All Authors: No reported disclosures

scholarly journals Effect of dithiocyano-methane on hexose monophosphate pathway in the respiratory metabolism of Escherichia coli

AMB Express ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yanfeng Chen ◽  
Wenjie Ke ◽  
Huabin Qin ◽  
Siwei Chen ◽  
Limei Qin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Control Group ◽  
Respiratory Metabolism ◽  
Hexose Monophosphate ◽  
Hexose Monophosphate Pathway ◽  
Response To Stress ◽  
Glucose Decomposition ◽  
Decomposition Pathway ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract This paper studied the inhibitory effects of dithiocyano-methane (DM) on the glucose decomposition pathway in the respiratory metabolism of Escherichia coli. We investigated the effects of DM on the activities of key enzymes (ATPase and glucose-6-phosphate dehydrogenase, G6PDH), the levels of key product (nicotinamide adenosine denucleotide hydro-phosphoric acid, NADPH), and gene expression in the hexose monophosphate pathway (HMP). The results showed that the minimum inhibitory concentration (MIC) and the minimum bactericide concentration (MBC) of DM against the tested strains were 5.86 mg/L and 11.72 mg/L, respectively. Bacteria exposed to DM at MIC demonstrated an increase in bacterial ATPase and G6PDH activities, NADPH levels, and gene expression in the HMP pathway compared to bacteria in the control group, which could be interpreted as a behavioral response to stress introduced by DM. However, DM at a lethal concentration of 10 × MIC affected glucose decomposition by inhibiting mainly the HMP pathway in E. coli.

Potential Public Health Significance of Non-Escherichia coli Coliforms in Food

1979 ◽  
Vol 42 (2) ◽  
pp. 161-163 ◽  
Author(s):  
ROBERT M. TWEDT ◽  
BRENDA K. BOUTIN
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Diarrheal Disease ◽  
Health Hazard ◽  
High Yield ◽  
Potential Health ◽  
E Coli ◽  
Potential Health Hazard ◽  
Health Significance

Several coliform species other than Escherichia coli are often associated with and possibly responsible for acute and chronic diarrheal disease. Recent evidence suggests that non-Escherichia coli coliforms may be capable of colonizing the human intestine and producing enterotoxin(s) in high-yield. Whether these organisms are newly capable of causing disease because of infestation with extrachromosomal factors mediating pathogenicity or simply because of inherent pathogenic capabilities that have gone unrecognized, they pose a potential health hazard. Food, medical, and public health microbiologists should be aware that the non-E. coli coliforms contaminating foods may be potential enteropathogens. This possibility may make determination of their pathogenic capabilities even more important than identification of their taxonomic characteristics.

High Yield of Active STb Enterotoxin from a Fusion Protein (MBP-STb) Expressed in Escherichia coli

1993 ◽  
Vol 4 (4) ◽  
pp. 275-281 ◽  
Author(s):  
C.E. Handl ◽  
J. Harel ◽  
J.I. Flock ◽  
J.D. Dubreuil
Keyword(s):  
Escherichia Coli ◽  
Fusion Protein ◽  
High Yield

scholarly journals Jabuticaba skin extracts: phenolic compounds and antibacterial activity

2018 ◽  
Vol 21 (0) ◽  
Author(s):  
Flávia Cíntia de Oliveira ◽  
Tamara Rezende Marques ◽  
Gustavo Henrique Andrade Machado ◽  
Thaís Cristina Lima de Carvalho ◽  
Aline Aparecida Caetano ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Listeria Monocytogenes ◽  
Phenolic Compounds ◽  
Methanolic Extract ◽  
Ethanolic Extract ◽  
Salmonella Choleraesuis ◽  
Pharmaceutical Industries

Abstract The phenolic compounds from various extracts of jabuticaba skin powder (JSP) were characterized in this study, and the antibacterial activity assessed. The phenolic compounds were extracted from the JSP using four methods: a) acetone extraction - 1 g JSP: 10 mL 70% acetone, resting for 2 hours; b) aqueous extract - 1 g JSP: 15 mL water, under agitation; c) ethanolic extract - 1 g JSP: 15 mL acidified ethanol, under agitation; and d) methanolic extract - 1 g JSP: 50 mL 50% methanol, under reflux. The antibacterial activity was evaluated by the agar diffusion assay, using Escherichia coli ATCC 11229, Salmonella choleraesuis ATCC 6539, Pseudomonas aeruginosa ATCC 15442, Staphylococcus aureus ATCC 6538 and Listeria monocytogenes ATCC 19117. The ethanolic and methanolic extracts showed the highest levels of phenolic compounds, especially of cyanidin chloride, catechin and epicatechin. The extracts did not inhibit the growth of Escherichia coli and Salmonella choleraesuis, but inhibited 30% of the growth of Pseudomonas aeruginosa with an extract concentration of 250 µg mL-1. Against Staphylococcus aureus and Listeria monocytogenes the highest inhibitory effect observed was 41.8% for the ethanolic extract, followed by 36% inhibition by the methanolic extract, thus revealing the potential of these extracts as possible alternatives for use in the food and/or pharmaceutical industries.

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