Photosynthetic production of the nitrogen-rich compound guanidine

Abstract

Direct photosynthesis of the nitrogen-rich compound guanidine from CO2 and N2.

Increased ethylene production by overexpressing phosphoenolpyruvate carboxylase in the cyanobacterium Synechocystis PCC 6803

“…It has been reported that nitrogen starvation (and other nutrient stresses) and arginine enhances the production of the nitrogen storage compound cyanophycin [41] and therefore arginine may not have been available for the Efe reaction under this treatment. Ethylene production is also accompanied by accumulation of guanidine inside cyanobacterial cells and in the medium, leaving less nitrogen available for arginine regeneration [42]. More research will be needed to understand the regulation of arginine metabolism in cyanobacteria, and to develop new strategy for improving ethylene production.…”

Comparative analysis of cyanobacteria species reveals a novel guanidine-degrading enzyme that controls genomic stability of ethylene-producing strains

“…Sll1077 is responsible for guanidine degradation in Synechocystis 6803. A comparative proteomic study of the wild-type Synechocystis 6803 and the guanidine-producing (efe-expressing) strain, JU547 26 , showed that the expression of Sll1077, a putative agmatinase, increased by 10-fold in strain JU547 compared to that in the wild-type Synechocystis 6803 (Table S1). Agmatinase cleaves the C-N bond within the guanidyl moiety of agmatine, which releases putrescine and urea 27 .…”

“…Although this seems already su cient for rendering genomic stability and sustained stable ethylene production in GD-EFE7942 (Fig. 6, S5), as well as the Synechocystis strain PB752 26 , it could be possible to obtain a more e cient guanidine-degrading enzyme, perhaps through directed evolution of Sll1077, in order to achieve faster degradation of guanidine and further reduce its toxicity in the future. In summary, this study has advanced our understanding of the biological routes of guanidine metabolism in nature and has demonstrated a new approach for enhancing biosynthesis of target molecule(s) by reducing toxic byproduct(s), focusing upon the speci c example of stabilizing ethylene production in engineered microorganisms.…”

“…E. coli NEB5α (New England BioLabs, MA, USA) served as the microbial host for cloning and maintaining all recombinant plasmids, and was routinely grown in LB medium. Synechocystis and Synechococcus strains were typically grown in a modi ed BG11 medium (mBG11) as described before 26 , and N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES) and NaHCO 3 were supplemented to nal concentrations of 20 mM and 100 mM, respectively, unless otherwise speci ed. The medium was ltered through sterile 0.22 µm membranes before use.…”

Monomer sequence design at two solvent interface enables the synthesis of highly photoactive carbon nitride

“…We expect, that during the pyrolysis, the creatine motifs interlinking the cyanuric acidmelamine lattices condensate to form a guanidine-like motifs, [HNC(NH 2 ) 2 ], which bind the heptazine units and modies the properties of the material (Scheme S1 †). 47 The formation of CN-like structures was conrmed by several means, FTIR shows the typical stretching vibrational modes of C-N heterocycles between 1200-1600 cm À1 and the breathing modes of the triazine units at 810 cm À1 (Fig. S6 †).…”