Isolation, structure, and potential biotechnological applications of the exopolysaccharide from Paenibacillus polymyxa 92. (15th March 2020) - Grinev, Vyacheslav S.
Highlights: Paenibacillus polymyxa 92 produced 38.4 g L −1 EPS in a medium with 10 % sucrose. DRIFT and NMR spectra showed that the EPS was a linear β-(2→6)-linked fructan (levan). Aqueous EPS solution showed pseudoplastic behavior and emulsifying activity. The levan-type EPS demonstrated heavy metal uptake capability. Pretreatment of wheat seeds with EPS increased the length of seedling roots and shoots. Abstract: Paenibacillus polymyxa 92, isolated from wheat roots, produced large amounts (38.4 g L −1 ) of exopolysaccharide (EPS) in a liquid nutrient medium containing 10 % (w/v) sucrose. The EPS was precipitated from the culture broth with cold acetone and was purified by gel filtration and anion-exchange chromatography. The molecular mass of the EPS was 2.29–1.10 × 10 5 Da. Diffuse reflectance infrared Fourier transform and nuclear magnetic resonance spectra showed that the EPS was a linear β-(2→6)-linked fructan (levan). Aqueous EPS solutions showed pseudoplastic behavior when shear stress was applied at different temperatures. By using the Ostwald–de Waele model, the rheological characteristics of the EPS solution were ascertained. The sorption capacity of the EPS for Zn(II), Cd(II), Pb(II), and Cu(II) was investigated. Sorption was maximal ( q = 481 mg g −1 ) for Cu(II) ions. In model experiments, treatment of wheat seeds with EPS solution significantly increased the length of seedling roots and shoots.