Effective whole cell biotransformation of arginine to a four-carbon diamine putrescine using engineered Escherichia coli

Genetically Encoded Multienzyme Particles for the Biosynthesis of Putrescine from l-Arginine

“…This performance was comparable to that reported for whole cells: in the study by Li et al, in which the Bacillus amyloliquefaciens was engineered with a synthetic ODC pathway, the whole cell catalysts produced 5.51 g/L putrescine after 48 h, with a productivity of 0.11 g/L/h and an overall product yield of 0.14 g/g xylose; in the study by Yang et al, the engineered E. coli cells overexpressing the enzymes in the ADC pathway attained a productivity of 8.56 g/L/h and an overall product yield of 0.41 g/g l -arginine after 2 h . Of note is the use of high concentration of cofactor PLP in the latter case (1 mM vs 0.1 mM in our system) …”

“…coli cells overexpressing the enzymes in the ADC pathway attained a productivity of 8.56 g/L/h and an overall product yield of 0.41 g/g l -arginine after 2 h . Of note is the use of high concentration of cofactor PLP in the latter case (1 mM vs 0.1 mM in our system) …”

“…After 12 h, approximately 430 mM (37.9 g/L) putrescine was produced (Figure S12), with a productivity of 3.16 g/L/h and an overall product yield of 0.435 g/g L-arginine. This performance was comparable to that reported for whole cells: in the study by Li et al, in which the Bacillus amyloliquefaciens was engineered with a synthetic ODC pathway, the whole cell catalysts produced 5.51 g/L putrescine after 48 h, with a productivity of 0.11 g/L/h and an overall product yield of 0.14 g/g xylose; 19 in the study by Yang et al, the engineered E. coli cells overexpressing the enzymes in the ADC pathway attained a productivity of 8.56 g/L/h and an overall product yield of 0.41 g/g L-arginine after 2 h. 22 Of note is the use of high concentration of cofactor PLP in the latter case (1 mM vs 0.1 mM in our system). 22 The resulting putrescine (∼430 mM; Figure S12) was retrieved after centrifugation of the reaction mixture and removal of the coimmobilized [hArg-Cry1Ab/ODC mut -Cry1Ab] particles (which could be reused in subsequent reaction cycles) and directly mixed with adipoyl chloride to synthesize the nylon-4,6 polymer.…”

“…Putrescine is a polyamine found in many organisms and its biosynthesis can occur via different enzymatic pathways. − Commercially, putrescine has many industrial applications, including as a precursor for the production of polyamide polymers, such as nylon-4,6, which is produced by the polycondensation of putrescine and adipic acid, and is commonly used in the production of biomedical instruments and textiles as well as automobile components. , Most putrescine used today, however, is chemically produced by the hydrogenation of succinonitrile, which is neither sustainable nor environmental-friendly, due to its use of nonrenewable propene as a raw material and the in situ production of the toxic intermediate hydrogen cyanide. , In an effort to minimize the negative impact on the environment, the biosynthesis of putrescine has been extensively explored, with nearly all efforts focusing on the engineering of microorganisms, with Escherichia coli being the most studied. In many of these whole cell systems, extensive genetic engineering was performed to overexpress the enzymes associated with two key putrescine synthetic pathways: (1) the ornithine decarboxylase (ODC) pathway that utilizes ODC to directly convert l -ornithine to putrescine and (2) the arginine decarboxylase (ADC) pathway that employs ADC and agmatinase to convert l -arginine to putrescine. ,,− Additional genetic modifications, such as deletion of putrescine degradation pathways and disruption of competing pathways of precursor utilization, have also been carried out in order to enhance the production of putrescine. ,− ,, Nevertheless, the amounts produced are generally low, in part because high concentrations of putrescine are toxic to the organisms. , …”

Modular bioengineering of whole-cell catalysis for sialo-oligosaccharide production: coordinated co-expression of CMP-sialic acid synthetase and sialyltransferase

“…Downregulating individual activities usually comes at the cost of a reduced overall (mass-specific) activity of the whole-cell catalyst [ 8 , 45 , 46 ]. A more promising strategy, yet one that is more challenging to realize, is to balance the individual activities at a high level of both [ 42 , 45 , 47 ]. CSS and SiaT both involve two-substrate reactions, with rates depending on the substrate concentrations in the usual (hyperbolic) way [ 41 ].…”