Eclipse3 system

SEC-MALS was performed to assess the oligomeric state of rXKR9. Ten micrograms of of purified rXKR9 was filtered through a 0.1 μm filter, injected onto a Superdex 200 Increase 3.2/300 GL column, equilibrated in LMNG SEC buffer, and run at room temperature on an Agilent 1260 Infinity II HPLC coupled with an Eclipse3 system equipped with a miniDAWN TREOS MALS detector and Optilab T-rEX refractometer (Wyatt Technology). Data was analyzed in the ASTRA software package. The dn/dc values used were 0.19 ml/g for rXKR9 and 0.132 ml/g for LMNG.

EPS samples were analyzed using the AF4 field‐flow fractionation technique (Fuentes et al., 2018) using an Eclipse 3+ system (Wyatt Technology, Dernbach, Germany) connected to a Dawn Heleos II (MALS) detector (Wyatt Technology, Dernbach, Germany) and an Optilab T‐rEX differential refractive index detector (Wyatt Technology, Dernbach, Germany), both operating at a wavelength of 658 nm. An Agilent 1100 series isocratic pump (Agilent Technologies, Waldbronn, Germany) with an in‐line vacuum degasser and an Agilent 1100 series autosampler delivered the carrier flow and handled the sample injection into the AF4 separation channel. A polyvinylidene fluoride membrane with a 100 nm pore size (Millipore, Bedford, MA, USA) was placed between the pump and channel to ensure that particle‐free carrier entered the channel. β‐Glucan standards (35 to 650 kDa) were used as molecular weight standards, in a concentration range of 0.01–0.1 mg/mL. The standards and EPS samples were delivered into the system in a liquid carrier containing 0.02% (w/v) NaN₃ and 10 mM NaNO₃ in Milli‐Q water.