Bioengineering

2081 KiB

Open AccessArticle

Applying Acylated Fucose Analogues to Metabolic Glycoengineering

by Julia Rosenlöcher, Verena Böhrsch, Michael Sacharjat, Véronique Blanchard, Christoph Giese, Volker Sandig, Christian P. R. Hackenberger and Stephan Hinderlich

Bioengineering 2015, 2(4), 213-234; https://doi.org/10.3390/bioengineering2040213 - 30 Nov 2015

Cited by 4 | Viewed by 7929

Abstract

Manipulations of cell surface glycosylation or glycan decoration of selected proteins hold immense potential for exploring structure-activity relations or increasing glycoprotein quality. Metabolic glycoengineering describes the strategy where exogenously supplied sugar analogues intercept biosynthetic pathways and are incorporated into glycoconjugates. Low membrane permeability, which so far limited the large-scale adaption of this technology, can be addressed by the introduction of acylated monosaccharides. In this work, we investigated tetra-O-acetylated, -propanoylated and -polyethylene glycol (PEG)ylated fucoses. Concentrations of up to 500 µM had no substantial effects on viability and recombinant glycoprotein production of human embryonic kidney (HEK)-293T cells. Analogues applied to an engineered Chinese hamster ovary (CHO) cell line with blocked fucose de novo synthesis revealed an increase in cell surface and recombinant antibody fucosylation as proved by lectin blotting, mass spectrometry and monosaccharide analysis. Significant fucose incorporation was achieved for tetra-O-acetylated and -propanoylated fucoses already at 20 µM. Sequential fucosylation of the recombinant glycoprotein, achieved by the application of increasing concentrations of PEGylated fucose up to 70 µM, correlated with a reduced antibody’s binding activity in a Fcγ receptor IIIa (FcγRIIIa) binding assay. Our results provide further insights to modulate fucosylation by exploiting the salvage pathway via metabolic glycoengineering. Full article

(This article belongs to the Special Issue Metabolic Engineering)

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1702 KiB

Open AccessReview

Metabolic Engineering of the Phenylpropanoid and Its Primary, Precursor Pathway to Enhance the Flavor of Fruits and the Aroma of Flowers

by Hadas Peled-Zehavi, Moran Oliva, Qingjun Xie, Vered Tzin, Michal Oren-Shamir, Asaph Aharoni and Gad Galili

Bioengineering 2015, 2(4), 204-212; https://doi.org/10.3390/bioengineering2040204 - 27 Nov 2015

Cited by 29 | Viewed by 9085

Abstract

Plants produce a diverse repertoire of specialized metabolites that have multiple roles throughout their life cycle. Some of these metabolites are essential components of the aroma and flavor of flowers and fruits. Unfortunately, attempts to increase the yield and prolong the shelf life of crops have generally been associated with reduced levels of volatile specialized metabolites and hence with decreased aroma and flavor. Thus, there is a need for the development of new varieties that will retain their desired traits while gaining enhanced scent and flavor. Metabolic engineering holds great promise as a tool for improving the profile of emitted volatiles of domesticated crops. This mini review discusses recent attempts to utilize metabolic engineering of the phenylpropanoid and its primary precursor pathway to enhance the aroma and flavor of flowers and fruits. Full article

(This article belongs to the Special Issue Metabolic Engineering)

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1348 KiB

Open AccessReview

Converting Sugars to Biofuels: Ethanol and Beyond

by Aram Kang and Taek Soon Lee

Bioengineering 2015, 2(4), 184-203; https://doi.org/10.3390/bioengineering2040184 - 27 Oct 2015

Cited by 57 | Viewed by 14343

Abstract

To date, the most significant sources of biofuels are starch- or sugarcane-based ethanol, which have been industrially produced in large quantities in the USA and Brazil, respectively. However, the ultimate goal of biofuel production is to produce fuels from lignocellulosic biomass-derived sugars with optimal fuel properties and compatibility with the existing fuel distribution infrastructure. To achieve this goal, metabolic pathways have been constructed to produce various fuel molecules that are categorized into fermentative alcohols (butanol and isobutanol), non-fermentative alcohols from 2-keto acid pathways, fatty acids-derived fuels and isoprenoid-derived fuels. This review will focus on current metabolic engineering efforts to improve the productivity and the yield of several key biofuel molecules. Strategies used in these metabolic engineering efforts can be summarized as follows: (1) identification of better enzymes; (2) flux control of intermediates and precursors; (3) elimination of competing pathways; (4) redox balance and cofactor regeneration; and (5) bypassing regulatory mechanisms. In addition to metabolic engineering approaches, host strains are optimized by improving sugar uptake and utilization, and increasing tolerance to toxic hydrolysates, metabolic intermediates and/or biofuel products. Full article

(This article belongs to the Special Issue Metabolic Engineering)

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Bioengineering, Volume 2, Issue 4 (December 2015) – 3 articles , Pages 184-234

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