“…It is also noteworthy that PAO1 showed at least twofold decrease in growth rate and maximum yield at elevated CO 2 . Based on sensitivity to CO 2 , heterotrophs range from those whose growth requires CO 2 under low CO 2 conditions (Kusian et al, 2002;Brown & Howitt, 1969;Bury-Moné et al, 2008;Kempner & Schlayer, 1942;Merlin et al, 2003) to those whose growth is inhibited by elevated CO 2 (Enfors & Molin, 1980;Gill & Tan, 1979), including organisms like P. aeruginosa that may exhibit both characteristics. In the former case, the need for CO 2 is attributed to CO 2 fixation in biosynthetic reactions, and CAs, as discussed above, are shown to be commonly required for survival of these organisms at low levels of CO 2 (Kusian et al, 2002;Burghout et al, 2010;Hashimoto & Kato, 2003;Merlin et al, 2003).…”