Characterisation of Films Based on Exopolysaccharides from Alteromonas Strains Isolated from French Polynesia Marine Environments

This work assessed the film-forming capacity of exopolysaccharides (EPS) produced by six Alteromonas strains recently isolated from different marine environments in French Polynesia atolls. The films were transparent and resulted in small colour alterations when applied over a coloured surface (Delta E-ab below 12.6 in the five different colours tested). Moreover, scanning electron microscopy showed that the EPS films were dense and compact, with a smooth surface. High water vapour permeabilities were observed (2.7-6.1 x 10(-11) mol m(-1) s(-1) Pa-1), which are characteristic of hydrophilic polysaccharide films. The films were also characterised in terms of barrier properties to oxygen and carbon dioxide. Interestingly, different behaviours in terms of their mechanical properties under tensile tests were observed: three of the EPS films were ductile with high elongation at break (epsilon) (35.6-47.0%), low tensile strength at break (C) (4.55-11.7 MPa) and low Young's modulus (epsilon m) (10-93 MPa), whereas the other three were stiffer and more resistant with a higher C (16.6-23.6 MPa), lower epsilon (2.80-5.58%), and higher epsilon m (597-1100 MPa). These properties demonstrate the potential of Alteromonas sp. EPS films to be applied in different areas such as biomedicine, pharmaceuticals, or food packaging.

Automated summary

This study assessed the film-forming capacity of exopolysaccharides (EPS) produced by six Alteromonas strains isolated from marine environments in French Polynesia. The films showed transparency and had minimal color alterations when applied over colored surfaces. Scanning electron microscopy revealed that the EPS films were dense, compact, and had smooth surfaces. The films also had high water vapor permeabilities, characteristic of hydrophilic polysaccharide films, and demonstrated different mechanical properties under tensile tests.