2.4.1. Determination of cell density and cell dry weight

The cell suspension OD_620 nm was measured, after adequate dilution with distilled water, using a WPA Biowave II UV/Visible spectrophotometer (Biochrom, Cambridge, UK).

Cell dry weight was determined by analytical weighing. Two milliliters of the culture liquid containing P. copri cells was centrifuged at 17,135×g for 5 min. Obtained cell pellets were separated from the supernatant and washed twice with distilled water, centrifuged repeatedly discarding water. Cell pellets were then resuspended in 0.5 ml of distilled water and the suspension was transferred to a pre‐weighed aluminum boat that had been dried overnight in an oven at 100℃. The boat loaded with suspension was then placed in an oven at 100℃ and dried overnight. During the drying time, the boats containing cells were measured periodically until no further decrease in dry weight was observed. The cell dry weight was estimated by calculating the difference between the aluminum boat weight before and after adding the cell suspension.