Zymomonas mobilis exopolysaccharide structure and role in high ethanol tolerance

Mateusz Pallach (1) , Roberta Marchetti (1) , Flaviana Di Lorenzo (1) , Antonio Fabozzi (1) , Eric Giraud (2) , Djamel Gully (2) , Luigi Paduano (1) , Antonio Molinaro (1) , Gerardino D’errico (1) , Alba Silipo (1)

1 Dipartimento di Scienze Chimiche, Complesso Universitario Monte Sant’Angelo
2 UMR LSTM - Laboratoire des symbioses tropicales et méditerranéennes

Bacterial cell surface exopolysaccharides (EPS) provide a protective barrier from the external milieu and participate in host-environment interactions. Zymomonas mobilis, an ethanologenic Gram negative bacterium, is used by the industry in bio-ethanol production process, due to its extraordinary resistance to a highly ethanolic environment. We found that Z. mobilis produces a mixture of two EPSs, an [alpha - (1 -> 6)-D-Manp] mannose homopolymer and a galactose containing polysaccharide: [-> 2)-beta-D-Galf-(1 -> 3)-beta-D-Galp-(1 ->](n). A physicochemical study, conducted with diffusion-ordered spectroscopy (DOSY) and Dynamic Light Scattering (DLS), allowed to demonstrate that, differently from the majority of polysaccharides, ethanol is a good solvent for the galactose containing EPS, revealing that its chemical structure is specifically connected with the Zymomonas mobilis high ethanol tolerance.

Mots clés: NMR spectroscopy; DLS; DOSI; ethanologenic bacteria; gram negative bacteria

Mots clés: exopolysaccharide; polymère; zymomonas mobilis; bactérie gram négatif; production; bioethanol

Domaines: Polymères; Autre

Mateusz Pallach, Roberta Marchetti, Flaviana Di Lorenzo, Antonio Fabozzi, Eric Giraud, et al.. Zymomonas mobilis exopolysaccharide structure and role in high ethanol tolerance. Carbohydrate Polymers, 2018, 201, pp.293-299. ⟨10.1016/j.carbpol.2018.08.072⟩. ⟨hal-01956110⟩