S648500

The levels of volatile fatty acids present in the supernatant of both co-cultures and monocultures were measured using an Agilent1260 Infinity HPLC (Agilent) system. The samples were prepared by acidifying to 5 mM, using sulfuric acid, and then incubating at room temperature for 5 min. Samples were then centrifuged for 5 min at 21,000 g. The supernatant was syringe filtered into an HPLC vial (Eppendorf FA-45–24–11) using a 0.22-µm polyvinylidene difluoride (PVDF) filter. The samples were analyzed using an Agilent 1260 Infinity HPLC (Agilent) system equipped with an autosampler unit (1260 ALS). The separation of formate, acetate, glucose, and lactate was carried out using a Bio-Rad Aminex^® 87H Ion Exclusion Column for organic acids (Part No. 1250140; Bio-Rad Laboratories, Inc., Hercules, CA, USA), with a mobile phase of 5 mM sulfuric acid. In-house standards were prepared with MC-blank culture medium as a base and sodium formate (ACS Grade, Fisher Chemical S648500), sodium acetate (ACS Grade, Fisher Chemical S210500), and L-lactic acid sodium (99%, extra pure; Acros Organics, 439220100), and D-(+)-glucose (Sigma-Aldrich Cat. No. G8270) at concentrations of 0.1 g/L and 1 g/L.

Levels of volatile fatty acids present in the supernatant of both co-cultures and monocultures were measured using an Agilent1260 Infinity HPLC (Agilent). Samples were prepared by acidifying to 5 mM using sulfuric acid and subsequently incubating at room temperature for 5 min. Samples were then centrifuged for 5 min at 21,000 g. The supernatant was syringe filtered into an HPLC vial (Eppendorf FA-45-24-11) using a 0.22 µm PVDF filter. Samples were analyzed on an Agilent 1260 Infinity high-performance liquid chromatography system (HPLC, Agilent, Santa Clara, CA) equipped with an auto-sampler unit (1260 ALS). Separation of formate, acetate, and lactate was achieved with a Bio-Rad Aminex^® 87H Ion Exclusion Column for organic acids (Part No. 1250140, Bio-Rad, Hercules, CA) with a mobile phase of 5 mM sulfuric acid. In-house standards were prepared with MC- blank culture medium as a base and sodium formate (ACS Grade, Fisher Chemical S648500), sodium acetate (ACS Grade, Fisher Chemical S210500), and L-lactic acid sodium (99%, extra pure, Acros Organics 439,220,100) at VFA concentrations of 0.1 and 1 g/L.