Characterization of microbial poly (ε-l-lysine) by FT-IR, Raman and solid state 13C NMR spectroscopies

Structural analysis of microbial poly(ɛ-L-lysine)/poly(acrylic acid) complex by FT-IR, DSC, and solid-state 13C and 15N NMR

“…[3][4][5] We have also characterized the structure and the conformation of e-PL and its derivatives in the solid state by 13 C and 15 N solid-state NMR. 6,7 These results indicated that e-PL is a semi-crystalline polymer with a crystallinity of B63%, as estimated by the measurements of 13 C spin-lattice relaxation time in the laboratory frame. A conformational model of e-PL was also proposed in which the main chain makes a parallel b-sheet similar to the g-form of nylon 6.…”

“…In Figure 3, the 13 C CPMAS NMR spectra of pure e-PL, e-PL/PAA complexes and pure PAA are shown. Assignments for e-PL 6 and PAA are shown in the Figures 3a and e, respectively. Peaks at B180 p.p.m.…”

“…A conformational model of e-PL was also proposed in which the main chain makes a parallel b-sheet similar to the g-form of nylon 6. 6 As tools for side chain functionalization, chemically modified derivatives of e-PL, e-PL/methyl orange (MO) and e-PL/dabsyl chloride (DC), were prepared through reactions of e-PL with MO and DC. In e-PL/MO, the side chain a-amino groups of e-PL are involved in ionic bonding with MO to form poly-ion complexes, (e-PL)-NH 3 + .…”

Phonon Dispersion and Heat Capacity in Microbial Poly(ε-L-lysine)(M-ε-PL)

“…24 This mode has been calculated at 1279 cm À1 at ¼ 0 and assigned to the peak observed at 1280 cm À1 in the observed Raman spectra. 14 Amide IV vibration is associated with the in plane bending of C=O band. This mode calculated at 549 cm À1 (at ¼ 0) is assigned to the peak appearing at the same value in the observed IR/Raman spectra.…”

“…Spectroscopic approach has proved a very powerful diagnostic tool in characterizing their conformation. Several workers [11][12][13][14][15] have studied the molecular structure and conformation of M-"-PL, which indicate that it assumes a sheet conformation. For example, Maeda et al…”