The ability of microbally produced poly(gamma,d-glutamic acid) to form stable polyelectrolyte-opposite charged surfactant complexes was investigated. A sonicated sample of polyacid with a molecular weight about 10(5) Da and a content of d enantiomer higher than 90% was used in this study. Nearly stoichiometric complexes of poly(gamma,d-glutamate) anions and alkyltrimethylammonium cations bearing linear alkyl chains with even numbers of carbon atoms from 12 up to 22 were "synthesized" by precipitation from equimolar mixtures of aqueous solutions of the two components. All complexes were found to adopt stratified supramolecular structures made of alternating layers of poly(gamma,d-glutamate) and surfactant with a periodicity increasing from 3.2 up to 4.3 nm according to the length of the alkyl side chain. No definite evidence indicative of the conformation adopted by the main chain in these complexes could be afforded. In all cases, the alkyl chains are in an extended conformation and oriented normal or nearly normal to the layer planes. Polymethylene chains with more than 16 carbon atoms were partially crystallized in the complexes in a separated paraffinic phase, whereas no crystallinity was detected for shorter lengths. The crystallized paraffinic phases were found to melt reversibly at temperatures between 40 and 70 degrees C. This process was found to happen with a concomitant expansion-contraction that amounts between 2 and 8% of the long period of the structure but without significant alteration of the layered arrangement.

A study of the production of poly(gamma-glutamic acid) (PGGA) by Bacillus licheniformis NCIMB 11709 grown on medium E in shake flasks at 30 degrees C is reported. The enantiomeric composition of PGGA was found to be highly sensitive to the concentration of Mn++, especially when the ion is present in small amounts (

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A combined viscosity–light scattering–gel permeation chromatography (GPC) study was carried out on bacterially produced poly(γ‐glutamic acid) (PGGA). PGGA samples with weight‐average molecular weights ranging from 8×104 up to 8×105 g·mol–1 dissolved in phosphate buffer at 0.13 M ionic strength were used. It was found that the Mark–Houwink relation is acceptably obeyed, giving K and a values of 1.84×10–6 dL·g–1 and 1.16, respectively. As expected, GPC analysis showed that PGGA does not follow the universal calibration plot and that deviations can not be avoided by modifying the ionic strength.