Structural comparison of TsFDH and CbFDH.

<p>Structural comparison of the A) N- and B) C-terminal loops of TsFDH (green, modeled using 2NAD) and CbFDH (cyan, pdb code: 2FSS). The elongated N- and C-terminal loops are shown in blue.</p

Determination of kinetic parameters.

<p>Correlation between the measured and calculated initial rates of TsFDH-catalyzed A) formate oxidation and B) CO₂ reduction; CbFDH-catalyzed C) formate oxidation and D) CO₂ reduction.</p

Sequence alignment of NAD-dependent FDHs.

<p>Amino acid sequences of FDH from yeast: CbFDH; FDH from fungi: CsFDH; FDHs from bacteria: AaFDH, MsFDH, PsFDH, and TsFDH. The blue background indicates the additional sequence regions for the N- and C-terminal loops of bacterial FDHs. Conservative amino acids are represented in red box and secondary structure elements are assigned according to the structure of CbFDH (pdb code: 2FSS).</p

Formate production through FDH-catalyzed CO₂ reduction.

<p>Formate production by (•) TsFDH and (▴) CbFDH in 100 mM sodium phosphate buffer, pH 7.0.</p

Enzyme activities of FDHs.

<p>Enzyme activities of FDHs for A) formate oxidation and B) CO₂ reduction at different pH values.</p

The kinetic parameters of FDHs^[a].

[a]<p>Kinetic parameters for the forward (formate oxidation) and reverse (CO₂ reduction) reactions were calculated by fitting the initial rates to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0103111#pone.0103111.e001" target="_blank">equation (1</a>).</p>[b]<p>Formate oxidation (A: NAD⁺, B: sodium formate).</p>[c]<p>CO₂ reduction (A: NADH, B: sodium bicarbonate).</p

Metabolic Engineering of Corynebacterium glutamicum for the High-Level Production of Cadaverine That Can Be Used for the Synthesis of Biopolyamide 510

Fermentative production of cadaverine from renewable resources may support a sustainable biorefinery process to produce carbon-neutral nylons such as biopolyamide 510 (PA510). Cost-competitive production of cadaverine is a key factor in the successful commercialization of PA510. In this study, an integrated biological and chemical process involving cadaverine biosynthesis, purification, and its polymerization with sebacic acid was developed to produce bio-PA510. To stably express <i>ldcC</i> from Escherichia coli in an engineered Corynebacterium glutamicum PKC strain, an expired industrial l-lysine-producing strain, <i>ldcC</i>, was integrated into the chromosome of the C. glutamicum PKC strain by disrupting <i>lysE</i> and controlling its expression via a strong synthetic H30 promoter. Cadaverine was produced at a concentration of 103.78 g/L, the highest titer to date, from glucose by fed-batch culture of this engineered C. glutamgicum PKC strain. Fermentation-derived cadaverine was purified to polymer-grade biocadaverine with high purity (99%) by solvent extraction with chloroform and two-step distillation. Finally, biobased PA510 with good thermal properties (<i>T</i>_m 215 °C and <i>T</i>_c 158 °C) was produced by polymerization of purified cadaverine with sebacic acid. The hybrid biorefinery process combining biological and chemical processes demonstrated in this study is a useful platform for producing biobased chemicals and polymers