||P.98 right column bottom paragraph: "Thus far, [investigators] have estimated the membrane demands of the electron transport chain, assuming that ATP is produced by a purely respiratory metabolism. Would less membrane area be needed if acetate fermentation was used instead? In other words, is acetate fermentation more surface efficient? A detailed calculation of the surface efficiency of both acetate fermentation and respiration can be found in Box 1.[They] find the membrane efficiency of acetate fermentation to be 15 ± 5 ATP/s/nm^2, significantly higher than respiration’s 4 ± 1 ATP/s/nm^2. Acetate fermentation can therefore produce the same amount of ATP as respiration using roughly a quarter of the membrane space, at the expense of a much lower ATP yield per glucose (primary source Neidhardt and Curtiss, 1996) (Box 1)."